Thursday, April 19, 2012

PC Hardware Redundancies

I see little point for people who obtain hardware simply to have it, i.e. pure collectors.  I do not consider most vintage hardware to have any artistic value, as if people are going to go "ooh" and "ahh" over that super-duper rare IBM computer you have in a display case.  It may start a short conversation, except among the like-minded, but otherwise in my opinion it simply takes up space.  In the PC world, most computers looked as at home on a factory floor as in an office.  Apple had some interesting designs around the time of the Mac II and the Apple IIc, and those trapezoidal function keys of the Atari ST and 130XE are truly unique.

I have held that function should hold over form.  My best example is when more advanced hardware totally eclipses less advanced hardware.  For example, why use an Adlib when a Sound Blaster does everything and more?  In most cases, unless you cannot find a Sound Blaster, there is none.  However, there are a few situations where you could find use for one :

1.  A strictly 80's PC with Adlib support, because the Sound Blaster was not available until 1990.

2.  Hardware conflicts with early Sound Blaster cards.  Sound Blaster cards, until the Pro, only supported digitized sound input and output using DMA1.  I am sure some other 8-bit expansion cards required DMA1 to function, SCSI or NIC cards for instance.  I know that the Tandy Sound DAC in the TL/SL/RL requires DMA1 and the Sound Blaster is utterly incompatible with it.  They hate each other.

3.  A mini PC where there is a really tight squeeze for a card.  The IBM PC/XT and XT/286 only supports short cards in two slots, and some Unisys compact desktops will only support short cards.  The IBM PC Portable can only support two long cards due to its design.  Most Sound Blasters extend beyond the edge of a 16-bit connector.

Even so, except for these specialized uses, there is no need for a true Adlib card.  The Sound Blaster is 100% compatible with Adlib software.  The same cannot be said for a Game Blaster and a Sound Blaster 1.0 or an upgraded Sound Blaster 1.5 or 2.0, because the Game Blaster software and some games will fail if they detect something other than a true Game Blaster.  You also have the same issues as 1-3 above.

On the video card front, EGA is generally not a 100% compatible substitute for CGA, but many non-IBM EGA cards do support Hercules graphics with a monochrome TTL monitor.  EGA is virtually 100% compatible with VGA cards, there is only a few titles that tweak the card in some way that most VGA cards will fail.  So unless you really want to use a 200 or 350 line digital RGB monitor, most people use VGA even for EGA games.

Since I mentioned Hercules graphics, why would anyone want to use that when they could use a color graphics card instead?  Well, beyond the "see how it looked" people, Hercules graphics can be a nice addition to a system.  MDA or Hercules graphics can happily co-exist with CGA or Tandy graphics.  You can setup a dual monitor display, but you cannot use both at the same time.  Typically, the MDA/Hercules would display everything using a text mode, and the color graphics card would be used for games and graphics programs.  It actually would be better if you hated CGA snow or the very slow screen updates in 80-column text modes that programs used to avoid it.  On the other hand, the long persistence phosphors of a mono TTL monitor is very different than what people are used to these days.

Unfortunately, nothing can really take the place of a Roland MPU-401 Midi Interface.  There are at least 45 major DOS games that will refuse to work correctly with a UART mode only compatible interface as found on the Sound Blaster 16, the Gravis Ultrasounds, Windows Sound System and Pro Audio Spectrums and Adlib Golds.  Given the midi hanging note bug that most of the Sound Blaster 16 and all the AWE32 and 32s express to some degree, having another card handle the midi interface chores is a good idea.

The Gravis Ultrasound.does not natively support the FM synthesis of the Adlib OPL2 or OPL3 and other sound cards also support digitized sound effects, so why bother using it?  If you are really into the DOS demo scene, that is one reason.  I do not really care about demos in general, I play games.  I have not encountered any game that exclusively supports the Ultrasound without supporting Sound Blaster.  The main issues are performance and sound quality.

Take Epic Pinball, which has great music.  This is one of those games that is a killer app for the card.  It supports the Ultrasound natively, none of this MEGA-EM or S-BOS emulation nonsense.  It supports 16-bit digital playback through the Ultrasound on a 386.  To get close to the same level of quality on a Sound Blaster 16, you need a Pentium for smooth gameplay.  Pinball Dreams, Fantasies and Illusions, Star Control II, there are other great games for the Ultrasound.  Even DOOM and DOOM II can use it for multiple audio streams.

Speaking of the Sound Blaster, should you choose the Pro or the 16/AWE32/AWE64?  If you have a 386 system, choose the Pro, since most games that run well on that tend to be slightly older.  If you have a Pentium, choose the 16-bit card, since that will provide the better sound quality for later games.  If you have a 486, you may wish to consider using both to get good compatibility at both ends of the spectrum.

A Sound Blaster Pro 1.0 is fully backwards compatible with the Sound Blaster 1.0 or 1.5.  The Sound Blaster 2.0 actually came out after the Pro 1.0, but is in between the two products in terms of functionality.  Actually, the Pro cannot support Game Blaster chips, so in a way it is not quite compatible with a 1.0.  This is unimportant for gaming purposes, since you can always put a Game Blaster card inside a system as well (if you can find one).  There will be I/O issues, however, at the cards' default 220 address.   Some games simply couldn't understand that some people may have to use one of these cards at a setting other than the default.

Two FM devices in a system is a recipe for trouble.  It is not a big concern if a game is merely writing to the chips, since you can always find a way to mute the unwanted output.  It becomes a concern if a game is trying to read the chips, since the values read may not be the same.  Usually, the status ports get read at the Adlib port 388H.  While only the status register can be read on an OPL2 or OPL3 chip, games use it to detect and calibrate their delays to write to an OPL2 chip.

PnP capable Sound Blaster cards have the ability to turn off their Adlib ports.  This does not entirely disable the FM of the Sound Blaster, since it can still be read at 2x0 & 2x2 (Pro or better) or 2x8.  However, this will avoid conflicts with programs that read (and write) to Adlib ports.  Moreover, games supporting the Sound Blaster 16 or better typically will allow alternate I/O, IRQ and DMA settings either through their setup programs or through the BLASTER variable.

The Gravis Ultrasound ACE is the only card in the Ultrasound lineup which can do the same thing, and it does it by a jumper.  My card is a 1.0 model, which unfortunately had a reversed stereo jack.  This is fixed in the 1.1 card, or through reversing cables.

Since this is a series of random observations, let me return to the Tandy.  In the hierarchy of sound autodetection, it goes PC Speaker, Tandy/PCjr. Sound, Adlib.  Items like the Game Blaster tend to hover around the Tandy category, and Roland MT-32 always gets manually selected.  If you have a Tandy 1000, I hope you are not nostalgic for PC Speaker sound because many games will force Tandy sound.  But Tandy graphics sometimes requires use of Tandy sound, even if there is an Adlib in the system.

In a Tandy 1000 *X or later, you can put an EGA card in the machine and games using the EGA mode.  Except for those games that use 350-line EGA graphics, the games look identical.  Many earlier games, however, will insist on using Tandy graphics.  Fortunately there is a program which allows you to switch between a graphics card and the built-in Tandy graphics.  Do can also do the same for VGA so long as you can find a card that works in an 8-bit slot and fits inside the Tandy.  Later games like Commander Keen require EGA due to their smooth scrolling effects, so they will only work on a Tandy 1000 RLX or one with an upgrade card.

Friday, February 10, 2012

DOS Games Joysticks & Other Gaming Device Support

1.  Influences

When IBM released the PC in 1981, it offered a joystick add-on card. An unusual choice for a company that was all business, but they were marketing the PC for the home as well as the classroom and the office. Since this was 1981, however, there were few predecessors from which to take inspiration. At that point, only Apple and Atari had computer systems with standard joystick/paddle interfaces. Atari's 400 and 800 had four digital joystick ports, each with one button. Each port could instead support a pair of one-button analog paddles.  The Apple II/II+ had a DIP-16 connector that could support up to four analog axes and three digital switch buttons. The Apple II interface was much simpler to build, so IBM took that as a guide.


2.  IBM Gameport Interface

A standard IBM joystick port uses a DA-15 (female) connector and can support up to four analog axes and four digital switch buttons. The stick connected to a pair of potentiometers, one for each axis, which the stick moved to register movement. This interface could support up to four paddles or two joysticks. I have never seen a paddle controller built for a PC.  Two joysticks can be used with an IBM interface with a Y-adapter or a card with two DA-15 ports.  This interface was known for its finicky nature, so the joystick makers used trimmers to adjust the range in which the potentiometers are moved.  There are two of these, one for each axis.

The IBM joysticks were a simple interface built around a 558 Quad Timer.  They are officially accessed at I/O 201, but since most gameports card do not completely decode the addressing around that address, usually anything from 200H-207H will work.  Each potentiometer is 100kOhms, compared to the 150kOhms of Apple II joysticks or the 1mOhms for the Atari paddle.  Three-terminal potentiometers are usually used, but the IBM interface normally only connects wires to two of them, +5V to one of the outer terminals and the middle terminal where the resistance is output.

When a value is written to the interface, that triggers the interface to convert the resistive load as given from the joystick to a digital pulse that will remain active proportionally to the resistive value.  The length of time measured reflects the position of the joystick.  The button state can also be read at this time. Normally, the button inputs are logically 1s (pulled up to +5V), but when the switch is pressed, the input is driven to ground.


3.  Early Joysticks (Kraft-style)

IBM did not release a joystick for the PC, but third party joystick makers quickly adapted Apple II sticks. The first generation of joysticks are generally these boxy things that have a stick that require a thumb and finger or two to manipulate. There are two buttons, one for the thumb and one for the forefinger. Kraft is the best known brand of this type.  The unique feature about these joysticks is that there are switches on the bottom to change the joystick from self centering mode to free-floating mode.  That is good for paddle games like Breakout and Arkanoid.


4.  IBM PCjr. Joystick

IBM did, however, release a joystick for the PCjr. Functionally it is the same as a regular PC joystick, except for the fact that it uses an 8-pin keyed BERG-style connector. Essentially it is a clone of the Kraft joystick and probably made by Kraft with an IBM label on it.  IBM had two distinct joystick ports of this type on the back of the jr. so there is no need for a Y-adapter.


5.  Tandy 1000 Joystick

Tandy Radio Shack, when it released its TRS-80 Color Computer, decided to use a design almost identical to the IBM standard. The differences are both cosmetic and functional. The Deluxe Joystick is a physical clone of the Kraft stick. It uses a 6-pin DIN connector and early models may not have the trimmer adjustments. When Tandy released the Tandy 1000 computers, they used the CoCo interface as it was fairly close to the IBM standard. The 1000 computers also have two distinct ports. IBM standard joysticks can be used in Tandy 1000 if you can make a pin adapter and connect the unused third terminal of each potentiometer to ground (which also connects the buttons). The (non-Deluxe) Joystick for the CoCo, a black box with one button, does work in these ports but is reported to be quite horrible to use.  Tandy also released a pistol grip joystick for the flight simulator crowd.

Unlike IBM Joystick potentiometers, Tandy joystick potentiometers connect the third terminal to GND.  The resistive signal is fed into a comparator against a a voltage source which charges at a constant time.  When the  voltages match, the interface informs the programmer, and the time it takes for the match to occur determines the joystick position.  The method is sufficiently different from IBM joysticks that some games may not work with Tandy joysticks.  Buttons are handled in the same way as IBM joysticks.


6.  Amstrad Joystick

Amstad PC clones, the 1512 and 1640 were unique in that it supported a digital joystick.  The interface (also used on the Amstrad CPCs) could use any standard Atari (CX-40) joysticks with a second button (on pin 7) which connected to a DE-9 connector.  The interface used keyboard scancodes, making joysticks function as if the user was using the numberpad.  Some games specifically support this method and more should have had these machines not been from the U.K.  The Amstrad could support more traditional PC joysticks through an add-on card.


7.  Hand-Grip Joysticks

By the late 80s, the boxy Kraft-style of joysticks were falling out of style.  Flight Simulators, such as the series from Microsoft, were becoming increasingly popular.  Joysticks increasingly looked like airplane flight sticks.  These joysticks required the whole hand to manipulate and usually had a trigger button for the crook of the index finger and a second button for the thumb.  They functioned in the same way as the Kraft-style joysticks, although some began to incorporate rapid fire switches for the buttons.  The base of the joystick was typically held down to the desktop with suction cups or a weighted bottom.

There were lots of no-name joysticks, but Advanced Gravis made a good one called the Analog Pro that pushed the limits of the standard interface.  This joystick had five buttons, one trigger, two thumb and two on the base.  Four buttons were independent.  It also had a throttle control which could be disabled.  The throttle uses the third joystick axis on the interface.


8.  Gravis Gamepad

The NES and its competitors in the console realm showed a different style of game controller, with a digital pad and face buttons.  For side scrolling and overhead arcade-style games, a large joystick was thought by many gamers to lack the precision required for tight movements.  Advanced Gravis, who had a reputation for making quality PC joysticks, released the Gravis Gamepad, which looked like a SNES controller with a D-pad on one side and four face buttons on the other.

The digital pad used a digital to analog converter in the pad to report the extreme values to the interface, as if the joystick were being pushed all the way in one direction or another.  For games that did not register movement beyond that from the extreme and neutral position, this was OK.  For games that did take the movement into account, the pad was less than an ideal device, if the game worked with it at all.  A screw hole in the middle of the D-pad allowed for the insertion of a stick for a more joystick-like experience.  Games like Commander Keen came bundled with the pad and considering the tricky controls of that game, nothing else came close to being as good to control it.  

The four buttons were the maximum the base PC interface could support.  There was a switch that could turn two of those buttons into rapid fire versions of the other two buttons.  The gamepad was also ambidextrous at the flick of another switch, so the buttons would get manipulated with the left thumb instead of the right and vice versa for the D-pad.  Additionally, Keen 4-6 had explicit support for the four button layout of the Gravis Gamepad or any joystick with all four buttons on it, so you could jump, use the pogo stick, shoot and check status without having to press two buttons at once.

Later Gravis Gamepads, like the Gravis Gamepad Pro, which looks like a regular Playstation controller and can allow for daisy chaining for up to four controllers, requires specific support with DOS games or a device driver in Windows.  The Microsoft Sidewinder gamepad, which looks like the precursor to the Xbox controller, requires the same.

9.  Speed Adjusting Gameports

As PC speeds began to increase and gamers upgraded their machines, sometimes their old games would not work with their joysticks, even though they worked fine with newer games and the interface was standard.  Gameports could be read by a BIOS call, Int 15H, Function 84H.  This BIOS call was available first on the IBM PC AT and later machines.  It is not available on any IBM PC, IBM PCjr. or an IBM PC XT or Portable with a BIOS dated 11/08/82.  Presumably the routines would be fine tuned to the CPU speed.  Programmers could also poll the Gameport using the system timer as a constant.  These methods are not speed sensitive.

Other games used timing loops dependent on the processor's speed to poll the gameport interface.  They would do this to achieve finer movement detection and possibly faster code.  However, as they rely on the processor's speed, this can be a problem when the processor is running too fast for the game to catch up.  So companies began to release gameport interfaces with a dial sticking out the back with multiple settings to have the interface match the speed of the processor.  I doubt that this always worked correctly.  One popular card was the Advanced Gravis Eliminator.

By the early 90s, gameports were increasingly seen on sound cards like the Sound Blaster, Adlib Gold and Pro Audio Spectrum.  Gamers could be disappointed because these cards implemented a straight gameport without any speed adjustment possible.  Also, the Sound Blaster combined midi in and out functions on the gameport, using one line for midi out and one line for midi in which had been previously connected to GND and +5V, respectively.  Do not connect a gameport to midi adapter to a straight gameport!  (Also, you cannot connect such a device to a Roland LAPC-I, which uses a DA-15 female as an MCB-1 substitute unless you rearrange pins in the adapter.  The LAPC-I does not support joysticks either).

Later gameport adapters, such as those found on the Sound Blaster 16, may allow gameport joysticks to work in faster computers like a 486DX2/66.  Earlier gameport adapters, like those that do not have any speed adjustment method or are found on 8-bit Sound Cards (including the Sound Blaster Pro) may fail to respond.


10.  Luxury Joysticks

In the 1990s, two companies were especially well known for making high end PC joysticks.  The first was CH Products Flightstick Pro, a high quality stick with four buttons, a 4-position hat switch and a throttle wheel.  The throttle used an extra axis, but the hat really added four extra buttons.  It required specific game support for the CH method, encoding the state of the eight buttons using a 4-bit binary code.  The downside to the CH method is that only one button or hat switch press could register at a time.  The method was compatible with games that did not support the encoding, as a button press would look identical to a standard stick.  To maintain compatibility, only 12 of the combinations are available.  The Flightstick Pro uses 4 combinations.  A later stick from CH had more buttons and hats and used most of the remaining 8.  They also made a flight yoke device called the Virtual Pilot, which had a special throttle control.  It was one way DOS games could get to having a proper wheel for STUNTS and Test Drive 3.  CH Products also released a standalone Pro Throttle which was programmable and could take over the third axis from the stick.

For the true sim fanatic, Thrustmaster came out with a three piece system that was made of real high quality materials and had the price to match :


FCS - Flight Control System, a standardish joystick with hat switch.  The basic stick was known under several names, including the P(ro)FCS, Mk I, Mk II, and Top Gun, etc.  Later versions include the F22 Pro and the F16 FLCS.  The later sticks were fully programmable directly because they had an AT keyboard connector in addition to the Gameport connector.

WCS Mk II- Weapons Control System, a throttle controller with six buttons and a three position switch, a later version with more buttons is the called the F16 TQS (Thottle Quadrant System).  There was an earlier version that looks virtually identical called the Mk I, but it is not programmable, only has preset keyboard combinations and does not use the gameport for the throttle action.  They connect to the system with a Gameport and AT keyboard connector.

RCS - Rudder Control System, a pair of floor pedals, a later version is called the Elite Rudders.  Although they may look like car pedals, they actually are pushed forward and pulled back with the heel, reportedly as an in airplane.

The combination of the first two is called HOTAS, hands on throttle and stick.  The buttons and hats on the FCS (except possibly the trigger) and WCS are programmable in software.  The programmable buttons and hats then acted like keyboard keys, and both devices could plug into the keyboard port for that purpose.  The keyboard would plug into a port on either device.

Connecting all this was a bit of an experience.  The Rudders had a joystick port which connected to the stick or the throttle.  The stick's joystick port connected to the throttle with a Y-adapter, and the throttle's joystick connector connected to the gameport.  The keyboard's connector was inserted into the stick, than a keyboard cable went from the stick to the system.  The gameport interface used two axes for the joystick, one for the throttle (a one axis device) and one for the rudders.  (I assume the rudders began at one extreme and pushing each to the limit would shift the direction by half).   Thrustmaster also made a true wheel called the Grand Prix 1 and a dual port gameport called the ACM Game Card with a speed dial and a second joystick interface at a default I/O 209H.

The hat switch on the standalone joystick works differently than on the CH Products sticks.  Each position on the hat is encoded to a discrete resistance value, which is then read on the third axis.  Five positions (up, down, left, right and center) equal five values.  A game had to have specific support for this method.  When the stick was plugged into a programmable throttle, the throttle would take over the axis and the hat buttons should be fully programmable.

11.  Notebook Options

In the DOS days, notebooks were very expensive business tools.  I cannot think of any notebooks offhand that came with a Gameport built in.  Many did have serial and parallel ports, and there were dongles that allowed you to connect a gameport joystick to a serial or parallel port.  Unfortunately, unless there was specific support for this hardware in a game, these dongles had to rely on drivers and TSRs to emulate the gameport.  Your mileage did vary in terms of compatibility.

There were PCMCIA gameport adapters.  I have one called the EXP Game Traveler.  There is another called the EXP Midi Traveler, which adds midi support to the gameport connector.  Both devices require drivers to load, but I did not have a problem with them.  Not common cards to find, for sure.  Look here for more info : http://www.expnet.com/know.nsf

12.  Mice and Six Degrees of Freedom Controllers

PC Games had been supporting mice since Microsoft Flight Simulator 2.0 in 1984.  The first mice used serial ports or proprietary interfaces to transmit data.  Mice and trackballs used a pair of rotary encoders to indicate movement on the x and y axes.  A standard Microsoft Mouse (including compatible mice made by third parties) supports two buttons.  Logitech mice often extended the protocol to enable support for a third button.  The Mouse Systems protocol always supported a third button, as did the PS/2 mouse protocol.  Tandy even made a mouse for its CoCo that could work in its Tandy 1000 machines, since it used 6-pin gameports with a special driver.

In DOS, a driver is required to enable mouse support.  The Cutemouse driver supports virtually any mouse ever made that can run in DOS.  Most people use it today because it takes up so little free RAM and is quite compatible.  A game does not have to have specific support for the mouse protocols because a driver will translate them into standard Int calls that are readily documented.  Sierra's SCI1 games supported the third mouse button for those games' point and click interface.  In those games, hitting the middle button will switch the icon from whatever it may be (eye, hand, item) to the walk icon.  PC Booter titles, which do not run on DOS, should only work with serial mice supporting the Microsoft Mouse protocol.

In 1996, Microsoft released its first Intellimouse, which popularized the scroll wheel.  A scroll wheel acts like a z-axis and third button.  It was released in serial and PS/2 versions.  I do not know that any DOS games that support a scroll wheel, which was mainly popular in Windows 95 programs.  However, there were at least two controllers that functioned like a mouse with support for a z-axis, the Logitech Cyberman and the Space Orb 360.


The SpaceTec SpaceOrb 360 (f/k/a Spaceball Avenger) looks like a gamepad with a trackball stuck on it.  It was great for Descent 2 and usable in Quake and Quake II.  The trackball can be pushed, pulled or twisted as well as rolled.  It has six programmable buttons.  The weirdness of the ball movement prevented it from achieving true popularity.


The first Cyberman was a mouse mounted on a pedestal, yet offered six degrees of freedom (6DOF).  It was supported in DOOM, System Shock and the floppy version of Quest for Glory IV.  It has three buttons.  You could move the mouse left and right (x-axis), forward and back (y-axis) and push and pull it up and down (x-axis).  You could also push forward/pull back the mouse relative to its base (pitch), twist it to the left or right relative to the x-axis (yaw) or the y-axis (roll).  It also has force feedback.  Unfortunately its poor ergonomics and limited ability to use it as a standard mouse made it unpopular.  Cyberman 2 was a Windows only device.

Monday, September 12, 2011

IBM PC Cards I Own or Have Owned

When considering my career in vintage computer collecting, I focused more on expansion cards than systems.  I had a hunger to acquire IBM PC ISA and to a lesser extent PCI / AGP cards.  I recently thought about what I have acquired in my career, what I have kept and what I have lost or sold/traded away.

Graphics Cards :

My early graphics card collection is among the best in terms of its comprehensiveness.  I have the following :

IBM Monochrome and Printer Display Adapter

It came with some system, and mine has a larger black bracket for IBM PC 5150 slots, so it will not fit well in other systems.  I have used it with the next card for dual monitor action.  However, only a purist would use it over a Hercules Card.  I also have an IBM 5151 Monochrome Display, which has moderate burn-in.  You can actually see images fade on the monitor, which is utterly unique.  Its parallel interface, like the standalone parallel card, can easily be modified into a PS/2-compatible bidirectional port.

IBM Color/Graphics Display Adapter

I have two of these cards, one of which I somewhat clumsily installed a pair of pin headers so I could choose the thin font.  I think it did something to worsen the video quality.  However, unless you only play text adventures, this card is an absolute must for gaming on an IBM PC/XT.  Other cards are not necessarily compatible or the speed becomes unacceptable.  I am also of the opinion that 256KB is an acceptable amount of RAM for any CGA game that does not support a superior graphics adapter.  There is no substitute for the IBM card, I also have an Epson CGA card that fails certain of Trixter's PC compatibility tests.  One huge advantage that this card has is that it can display color through its composite RCA jack.  While DOSBox, MESS and PCe Emulator can display 640x200 graphics as composite artifact color, they cannot do the same for 320x200 graphics, which usually display in color on a composite monitor or TV.  Games exist that take advantage of this functionality.

Hercules Graphics Card

This is a long card with no additional support.  Hercules later marketed a Plus card with support for user replacable text fonts and an InColor card with 320x200x16 color support.  Some games support the latter, but also support EGA with one exception (Karateka).  I had two of these cards, but sold one with a utilities disk from Hercules.  Unfortunately, I did not have a 5.25" drive at the time, so I could not image the disk.  I do not know if there is a software setting to turn the card into half-graphics mode, which only uses 32KB instead of the card's 64KB.  There is no jumper on the board for this.  The graphics tended to be a bit slow on IBM PC and XTs, however some games use the monochrome graphics well.  Look at Sierra's AGI games for example.

IBM Enhanced Graphics Adapter

Not only do I have the base adapter, but also the RAM expansion daughterboard for a full 256KB.  I have no desire to obtain a Professional Graphics Adapter, as no game I am aware supported it.  The RCA jacks go directly to the expansion connector, and the functions of the switches are not immediately obvious.  Unfortunately I have never owned a 350-line color TTL monitor, so the 640x350 mode is beyond my reach.  This adapter will work just fine with my 5151 and 5153 monitors if the switches are properly set.

IBM PS/2 Display Adapter

This is IBM's only 8-bit VGA graphics card and probably its only ISA card with its own VGA chipset (as opposed to another manufacturer).  It is a full length card with two rows of pin headers for some unknown purpose and a VGA feature connector.  I am concerned that its EPROM may eventually die, but I dumped it just in case.  It will even work in a Pentium II/III system with ISA slots, even if the system beeps.  It will also work fine in an IBM PC 5150.   It was designed to upgrade an IBM PS/2 Model 30 from MCGA to VGA, but it can work in many other systems.  (It would not fit in a PS/2 Model 25).

Unusually, it only uses 24KB of a 32KB EPROM, which is mapped from C0000-C5FFF.  It also has 8KB of sratchpad RAM, but this is mapped in a very weird way.  6KB of it is mapped from C6800-C7FFF and the remaining 2KB is at CA000-CA7FF.  There are memory holes in between, so if you are using a card with an External ROM, make sure it does not start at C8000 if you are using this card.

My later acquisitions include :

Diamond Monster 3D Voodoo Graphics

I remember owning one of these back in the day, so I bought another for those early DOS/Win 9x games which do not work properly with a a later generation Voodoo 2 card.  One day the card refused to display graphics, just some white lines on a black screen.  Eventually I threw it away.

Diamond Monster 3D II 12MB Voodoo 2

I remember replacing my Voodoo Graphics with a Voodoo 2 back in the day, but I do not believe I ever had two cards for an SLI configuration.  I am sure I replaced it by 2000 for a Geforce 256.

3dfx Voodoo 5 5500 AGP

This card was a replacement for the MAC card, but eventually it could no longer display graphical modes without severe corruption, so it too went into the trash.

3dfx Voodoo 5 5500 MAC PCI

I bought this card on eBay from a guy in China, and noticed that the card's faceplate was very rusty.  Once I flashed the card with a PC BIOS, it worked well, even its DVI connector.  Eventually the VGA output would not display the color green, and an unknown component in a set of three looked damaged, so I eventually threw it away.


IBM Cards :

IBM Printer Adapter

This card would have been used to add LPT1 to a system with a CGA card or LPT2 to a system with an MDA card.  The usual address is 0x378h, but it can be hacked and I did hack it to be selectable to 0x278h.

IBM Asynchronous Communications Adapter

This card could reliably handle null-modem transfers at 9600 baud, whereas the UART on my AST Six Pak Plus could only do 4800 baud null-modem transfers.  Has one jumper DIP block to select COM1 or COM2, another to select TTL or current loop communication.  My card has a jumper to work in the IBM XT's slot 8.  

IBM Game Control Adapter

This card may seem useless, as it has needs a Y-splitter for two joysticks and has no speed adjustment, but its useful to have a card, the compatibility of which, is assured.

IBM Diskette Drive Adapter

Has a card edge and can support 5.25" or 3.5" double density drives.  If you need a custom cable because you installed a 3.5" drive with only a pin connector, you should be able to squeeze on an extra connector to a cable easily.

AST Six Pak Plus

This card came with my IBM PC 5150, and it can complete a PC if everything is properly installed.  IBM even marketed it in some of their late brochures.  It can add 384KB of RAM to the PC's Motherboard's 256KB for the full 640KB.  It can also add a serial, parallel and game port.  Each of these ports can be disabled.  The parallel port requires a DB-25 female header and the game port a DA-15 female header, a N558 Quad Timer and a 74LS244 chip.  The serial port has a socketed UART.

Sound Cards :

Adlib Music Synthesizer Card

There are two versions of this card, the 1987 version and the 1990 version.  Other than an extra capacitor or two on the 1990 version, the only difference is that the 1987 version uses a 1/4" TRS output jack and the 1990 version uses a  3.5mm mini-jack.  Output is mono, and the silkscreening on the YM-3812 and Y3014 OLP2 chip and DAC is scratched out on my 1990 version card, although by that time the secret of what chip Adlib was using was out.

IBM Music Feature Card

I originally purchased this full length card for a hefty sum on ebay.  It came with a midi breakout box, which I acquired separately a year later.  Later I traded it for something, a trade I occasionally regret.  Only Sierra On-Line ever supported it in games, but they supported it for a four year period (1988-1991).  It is a combination of a Yamaha FB-01 midi music synthesizer (using 4-op FM synthesis) and unique IBM midi interface.  I put it in a PC and used the breakout box to try and replicate an FB-01, but DOSBox would not produce the correct sounds.  That was about 3 years ago, but there are versions of DOSBox available on VOGONS that will transmit the MIDI properly to the card or FB-01.  A Yamaha FB-01 works well with most games and a Roland MPU-401 interface.

Roland MPU-IPC-A + MPU-401

As I have stated previously in this blog, the MPU-IPC-A is merely a small logic card, and the MPU-401 is the external box where all the midi commands and data is processed.  It makes no music unless attached to a midi synthesizer, whether a keyboard or a module.

Roland LAPC-I

I bought this, with its MCB-1 midi breakout box, from a seller for $25 + shipping.  He did not know if it worked and this was a risk.  This was back in 2006 or so before the price of an LAPC-I skyrocketed.  I could put it in a PC and use it as an external synthesizer in DOSBox, but I needed a program that allowed sysex to pass through the midi interface to the synthesizer.  The interface by default would block sysex, which would eliminate the synthesizer's ability to receive custom sounds from a game.  I traded it for something good after I had acquired a CM-32L, which has the exact same synthesizer capabilities.  My card had ROM v1.02, not EPROM, which was v1.00.

Creative Labs Game Blaster

My most recent acquisition came as a part of a trade for a Tandy 1000 TL.  It came in its retail box with driver disks on 5.25" and 3.5" disks and the Sierra game Silpheed, also on both disk formats.   I wanted this because there are games which I have confirmed will not work with a Sound Blaster with C/MS chips, they obviously are looking for something inside that big CT-1302 chip.  The next widely-available CL card using RCA jacks would be the AWE64 Gold.  It is a stereo card, but that was probably the only thing for which it was known.

Creative Labs Sound Blaster 1.5 w/CMS Upgrade

The earliest Sound Blaster cards came with a v1.xx DSP, but mine came with a v2.00 DSP.  I added the C/MS chips, which are Phillps SAA-1099s.  That is the only part of the card in stereo.  With the v2.00 DSP (which adds auto-DMA support among other things), I have cajoled Trixter's 8088 Corruption demo to work with the card.  I read that the v2.00 DSP was necessary for MPC-1 compliance with Windows 3.x multimedia features.  I may keep it around only to check whether C/MS games will work with the card, but DOSBox now supports the Game Blaster.

Creative Labs Sound Blaster 2.0

I sold this card because I could not upgrade it with C/MS chips because it uses an extra PAL chip, a 16L8N, the programming for which nobody was able to replicate at the time.  It would have worked as well as any Pro in any game except for stereo and mixer support.  Its abilities are firmly encompassed by other cards.

Creative Labs Sound Blaster Pro 1.0

I kept this card because there are games that support its dual OPL2 chipset.  It is also necessary if you wish to use a Sound Blaster with any Tandy system with a PSSJ sound chip.  The PSSJ only works with DMA1 and if a Sound Blaster is also set to DMA1, games will freeze when playing sounds.

Creative Labs Sound Blaster Pro 2.0

Although I sold this, it has one big advantage over the Pro 1.0.  The OPL3 chip on this board is not not particularly sensitive to system speed, whereas the OPL2 chip is (like the game port and a rev 0 MT-32).  If you run an older game on say a Pentium system, the game may send the data to the OPL2 chip so fast that it cannot process all the data, and the music will be incorrect.  However, the Sound Blaster 16s I have also have true Yamaha OPL3 chips.  Although Windows 9x does support the Sound Blaster and Pros, their 8-bit limitations will show themselves in garbled 16-bit audio playback.

Creative Labs Sound Blaster 16 MCD ASP & Creative Labs Sound Blaster 16 SCSI-2 ASP

This card is the bare minimum which modern programs can use, since it can do stereo 16-bit playback at 44,100kHz.  I originally got the SCSI-2 CT-1770, but I did not like the fact that the SCSI interface used an extra high IRQ and eventually traded it.  I acquired a MCD CT-1760, and the proprietary CD-interfaces on that card can have their IRQ usage disabled.  Both my cards have a soldered ASP chip (TFX uses it) and use DSP 4.05 for error free midi playback through the waveblaster or the external midi out.  The waveblaster port does no favors for the output of a midi daughterboard.

Creative Labs Sound Blaster AWE32

When I bought this card, a CT-2760 rev. 3, I soon discovered that I had no case in which to put it.  My Pentium II/III system uses a modern case with a hard drive cage going all the way down the case.  This blocked the card, which is a full-length 13" ISA card.  Also, the plastic tabs that held the SIMMs in place were broken.  Gravis used much more durable metal clips in their PnP.  I only used it once or twice by removing the motherboard from the case, which was unwieldy to say the least.  I eventually donated it to a friend of mine who was interested in the rev. 3.

Creative Labs Sound Blaster AWE64 Gold

This card was superior to the 16s and the AWE32s in almost every way.  I did not care about the lack of SIMM slots or waveblaster connector.  However, ISA PnP is no fun and its FM Synthesis is lacking in quality.  Unlike the early AWE cards, which used genuine integrated Yamaha OPL3 core, Creative was using its CQM substitute by this time.  Although the sound is close, it is not the same and usually sounds harsh.

Gravis Ultrasound ACE

This card I picked because it had perfect GUS playback capabilities.  My board came with driver disks and thick manual.  It also came with the maximum 1MB of RAM.  It has one soldered SOJ chip and one socket for an additional SOJ chip.  Unlike an original GUS or GUS MAX, it does not support a daughterboard for 16-bit recording, but I have no interest in recording anyway with an ISA card.  Its Adlib emulation, which uses I/O 388/389h can be disabled, which eliminates conflicts between the real thing.  It does not have a joystick/midi to further reduce configuration headaches.  Unfortunately, this is the 1.0 version, which means the output jacks have reversed stereo.


Gravis Ultrasound PnP

This card embodies the true 2nd Generation of Ultrasound sampling technology.  Unfortunately, games did not really support the extra features of this card.  Mine (v1.0) does not have any RAM soldered on the board but has both SIMM slots populated.  2MB of RAM is on my card, which ensures full Ultrasound compatibility and not much else.  I prefer the ACE over this card because this is a dreaded PnP card and its RAM usage is far from unique in Windows 9x.

Roland SCD-15

This is the official name of the marketed combination of a Roland MPU-401/AT ISA MIDI Interface Card + Roland SCB-55 daughtercard.  It has these mini-DIN connectors which were always hard to find.  Creative Labs had mini-DIN connectors for their Live! and Audigy breakout boxes which worked, but their support site did not always have them in stock.  The daughterboard was almost as big as the card itself and the card hung off it.  In fact, although the daughterboard had four standoffs, only two actually connected to the board.  This did not seem like a stable long-term solution, so I traded it away.

Yamaha DB50XG

I also got one of these, although the DB60XG is more common on eBay.  The former is a retail product, while the latter is an OEM product.  The former has the advantage of at least partial support for Yamaha QG300 synthesis custom voices.  The Fat Man really expoused the virtues of this card, and some games either supported it or were attuned to sound good with it.  I avoided the SW60XG because it had no external midi port.  When I finally acquired a MU10XG, I traded this away.

Yamaha YMF-724/744/754 Cards

I do not talk about PCI cards much here, but these were a very good solution for backwards compatibility with the Sound Blaster.  Most late ISA and PCI card emulated the Adlib OPL2/3 FM synthesis poorly or inaccurately, but these cards came from Yamaha and incorporated a true OPL2/3 core into the chip.  They also supported the PC/PCI connector found on some TX/LX/BX motherboards or D-DMA for TSR-less digital Sound Blaster compatibility.  Finally, some cards also supported S/PDIF output for crystal clear sound.  Pure FM recording with these cards is quite possible.  I have not tested it, but 4-speaker sound output is available in 744 and 754 cards.  But there are some drawbacks :

While the digital sound blaster emulation is good, it is not perfect and only goes up to an SB Pro.  Fortunately, very few games require a Sound Blaster 16 or better. Fallout for DOS had broken SB/SB Pro drivers, but I used drivers from another other Interplay game to get the SB/SB Pro sound working again.  It will not emulate Sound Blaster ADPCM 8bit-3bit and 8-bit-2bit modes, which Duke Nukem II among others use for some sound effects.  Since games use direct I/O access for the Sound Blaster and Adlib, the card may not work in Windows XP or other NT machine.  The card supports DirectSound and DirectSound 3D and emulates EAX 1.0 through Sensura, but the surround sound causes system performance issues.  Finally, most motherboards for the Pentium/II/III have at least one ISA slot, so why not use a true ISA Sound Blaster?

Aureal SQ2500

The ultimate card for A3D support, I picked it because it represented the last card to support a widely used but eclipsed technology.  No other card except the Aureal AU8830 supported A3D 2.0, other cards only went up to 1.0.  It supported 4-speaker output, but the rear speakers were not as widely used as the front speakers.  Games that support A3D 2.0 include Half-Life, Descent 3, Unreal and early versions of Quake III.  It also has a waveblaster header.

MIDI Modules :

Roland MT-32

My MT-32 was something of a late purchase as I did not fully understand the need for one or the unique character of the LCD display.  It is very convenient to be able to reset the module by pressing Master Volume and R at the same time.   Other modules require a shutdown or sending a reset command via midi.  Viewing messages on the LCD which games display is always neat.  Mine is a rev 0 ROM v1.07, which is the last ROM version before the 2.x versions, exclusive to rev. 1 boards.  The MT-32 works great in DOSBox, which can easily adjust transmission speed to be slow enough for an MT-32.  I would say 3,500 cycles is the limit if the game is transmitting custom patches.  Since I am a big fan of Sierra games, I want to know how these games sounded, and some of them exploited bugs of the rev. 0 boards.

Roland CM-32L

Being unhappy with my CM-64 and CM-500, I turned to this, simpler model.  No slot, no mode switch, only an on button.  Necessary for games that causes errors on the MT-32 regardless of speed or use the extra sound effects of the rhythm/percussion part.

Roland CM-64

After learning of the CM-500's vibrato issue, I turned to this module, a true combination of CM-32L and CM-32P.  Unfortunately another issue reared its head.  Sierra's SCI games music synthesis engine broadcasted  MT-32 data on midi channels 2-10 and Adlib data on channels 11-16.  The MT-32/MT-100/LAPC-1 and CM-32L did not care, as they did not use channels 11-16.  The CM-32P does, and wrong sounds would constantly be heard.  Later Sierra drivers eliminate the issue, but they will not work with the early versions of King's Quest IV and Leisure Suit Larry II.  Also, this may occur in other games, although this is unlikely.  Although the CM-32P was supported in some Japanese NEC-98xx and X68000 games, my primary interest is DOS, so a better solution was found in a simple CM-32L, and this got traded.

Roland CM-500

When I was first collecting vintage hardware, this module was seen as the Holy Grail of Roland LA Synthesis and expensive and rare even then (2005).  It does support the Roland SC-55 GS (and later General MIDI) synthesis engine and the Roland CM-64 (emulating the CM-32P).  Unfortunately, not only does it share the same issue as the CM-64, it was pointed out that it had annoying Vibrato.  So it got traded.

Yamaha MU10XG

This external synthesizer used the same synthesis engine as the DB50XG and SW60XG, so I knew it was a quality card.  It was also hard to find, I guess it was not very popular.  Unusual for an external module, it has a battery compartment.  It also has two 1/4" audio input jacks to which the module can apply reverb and other effects.  It requires a +12v adapter, so I used an adapter from something completely different that fit.  It has not gotten much use because DOS games generally composed for Roland LA or GM.

Roland SC-55

This was a relatively recent purchase.  It came with a remote control, which I have somewhere.  Like the MT-32, it has a display and there are games that take advantage of it (Lands of Lore).  Mine is a GM/GS module, which came later than the original, GS only modules.  It makes no difference in functionality whether the module supports GM and GS or just GS.  Also, there is the stargame.mid, which uses the equalizer to display graphics.  Its only downside is the 24 voice polyphony, but the quality of the sounds with effects more than makes up for the deficiency.

Roland SC-55ST

I thought this was better than the original SC-55 in every way, but it turns out not to be the case.  The original SC-55 had a Capital Tone Fallback feature that if a game tried to play a variation tone which the module did not have, the module would play the capital tone instead.  Yamaha also used this technology and forced Roland to remove the feature from the 2nd and later generations of Sound Canvases.  Unfortunately, there are games that use this functionality (Might and Magic IV & V, Space Quest V, Lands of Lore).  It gets little use as a consequence, as the SC-55 has much more character.

Sunday, August 7, 2011

Tandy 1000SX - The Best Overall Choice for IBM PC Gaming of the 1980s


Back in the 1980s, if you wanted to play games on a computer, there were many incompatible options available.  If you were on a budget, you may have had a Commodore 64.  If you were a real computer geek, you may have appreciated the open system of the Apple II.  Of course, your parents may have made the unfortunate choice of buying a Coleco Adam, Mattel Aquarius, TI-994A, a Commodore PET or TSR-80 or Color Computer.  None of these machines were particularly good for gaming.   You may have had the awesome parents that would have bought an Atari 8-bit computer or the VIC-20, which were great for games and very little else.  But later in the 1980s there were fewer options, in no small part due to the acceptance of the IBM PC in the business world.

In the second half of the 1980s, the 6502-based systems like the C64 and Apple II were really starting to show their age and the Atari machine was virtually dead.  In response, Commodore, Atari and Apple introduced new computers, the Amiga, ST, Macintosh and IIgs respectively.  The first two never caught on in the North American market, the Macintosh suffered from a lack of a color screen and gaming hardware early in its life and the IIgs withered on the vine due to a perceived slow processor and apathy from Apple.

From 1981-1986, the IBM PC line had become a huge success in the business world, but the high prices of the offerings from IBM did not make for much enthusiasm from the home market.  Even in 1987, just before IBM discontinued the line, the most basic configuration of the IBM PC cost a list price of $1,165.00.  This configuration only came with 64KB of RAM, no floppy or hard disk drive or adapter, no monitor or graphics card, no software, no game controller adapter.  To get a working configuration you would practically have to double the price.  For that year, the PC was a slow machine.

IBM's one effort to market a machine to the home user during this decade was the PCjr from 1983-1985.  The Jr. failed for reasons that are widely known, namely that people were expecting a fully PC compatible machine and got something significantly less than compatible, had a terrible chicklet keyboard, limited and proprietary expansion options, and was not especially competitive with other home computers at the high price point of $1,269.00.  If the PCjr. could not escape the shadow of its big brother and its own shortcomings, it did have some influence.  First, it was designed to be easier to get up and running.  If you got the expanded model, there was little need to open the machine as everything attached to the back or was bolted onto the side.  It had lots of built in hardware that were extras on a PC.  It had a built-in custom graphics controller that had better capabilities than the Color/Graphics Monitor Adapter found on the PC and could connect to a digital RGB or analog composite color monitor.  Comparable but incompatible graphics were available on the Enhanced Graphics Adapter, which was hugely expensive at the time.  It had a three-voice sound chip in addition to the PC Speaker and could mix external audio from a sidecar and had an audio RCA output.  All the above did not exist on the PC.  It had a serial port and a game port with plugs for two joysticks, which were extra add-in cards on the PC.  Perhaps in part to offset speed issues with RAM shared between the CPU and the Graphics Controller, the machine had two cartridge slots for games and programs.

Tandy Corporation, which operated the Radio Shack chain of stores, had a very active home computer division which had already produced the aging TRS-80 and not-exactly a sales leader Color Computer lines. Tandy had designed an MS-DOS machine called the Tandy 2000, which was at best semi-compatible with the PC and was hardly a best-seller.  The home market was crying out for affordable PC-compatible machines, and Tandy liked the PCjr.'s features and thought they could do better at the price point.  They developed a machine that supported the PCjr.s features and offered mostly better PC-compatibility.  Unfortunately, in 1985 as the machine was about to be released, IBM discontinued the Jr.  So Tandy began to emphasize MS-DOS and PC compatiblility for the machine, the Tandy 1000.

The Tandy 1000 came with a 8088 running at 4.77MHz, just like a PC, 128KB of RAM (shared with graphics),  the 90-key Keyboard used in the Tandy 2000, two joystick ports using joysticks from the CoCo, the same graphics and sound capabilities as the PCjr., composite video and digital RGB support, a printer port.  Its keyboard and joystick ports were at the front of the unit whereas IBM's were always at the back.  It had a reset button whereas IBM users had to press Ctrl-Alt-Del.  It ditched the cassette and cartridge ports of the Jr., the wireless keyboard and avoided proprietary ports to a greater extent than the Jr.  It came with a 5.25" floppy disk as standard and had the floppy controller circuitry built into the motherboard.  MS-DOS 2.11 and GW-BASIC came with the machine (no separate purchase required) as did DeskMate (Office App).  Unlike the PCjr. with its one drive bay, the 1000 came with two.  Its weaknesses included :

Only 3 XT/8-bit ISA slots

RAM upgrades only by special Tandy upgrade cards took up 1-2 ISA slots to get to 640KB.

No Serial port

No DMA built-in, came on one of the RAM upgrades.  This gave a stock 1000 the same kind of annoyances as the Jr. (CPU servicing disk drive, leading to ignored keystrokes, keystrokes interrupting serial data).

No ability to disable graphics circuitry (no upgrades to EGA or VGA)

No socket for a Math Coprocessor.

The Tandy 1000A added a math coprocessor socket and fixed some bugs.  (Tandy offered a version called the 1000HD with a 10MB hard drive and a 640KB RAM & DMA upgrade board that came on 1 board instead of 2).  The IRQ for the hard drive was 2 for these Tandys, with IRQ 5 used for the video.  IBM used the opposite designations for the PC line.

The next models in the series, released toward the end of 1986, are the Tandy 1000 EX and 1000 SX.  They are functionally the same machine, but the EX is a compact model with only one drive bay and the need to use Plus card for expansion with room for only three and an external drive port for a second disk drive.  The RAM and DMA upgrade comes on a Plus card.

The Tandy 1000 SX, the machine in question fixes virtually all the above issues.  It has 5 XT/8-bit ISA slots, can be upgraded to 640KB of RAM on the motherboard, can support an EGA or VGA card and a hard disk controller and a math coprocessor.  It came with 384KB standard RAM, a DMA chip and used standard 256Kx1 chips to upgrade to 640KB.  It came with MS-DOS 3.2, which added support for 720KB drives.  It could boot from either drive, which is useful if you have bootable 5.25" and 3.5" disks.  It ran is 8088 at 7.16MHz or 4.77MHz for a decent speed boost.  This speed is selectable on bootup for software expecting the slower speed.

Later models in the 1000 series added support for a 286 processor (TX), DOS-in-ROM (HX), 768KB of RAM so graphics memory would not conflict with conventional memory (TX), high density floppy controller (RLX & TL/3), 8-bit IDE interface (TL/2, RL), 3.5" drives as standard (TX & HX), improved graphics with 640x200x16 mode (TL & SL), enhanced sound with Digital-to-Analog and Analog-to-Digital conversion (Tl & SL).

Here is how I have my Tandy 1000 SX configured

Monitor :
Tandy CM-11 High Resolution Color Monitor

Keyboard :
Tandy 1000 Keyboard

Drive Bays :
5.25" 360KB Drive
3.5" 720KB Drive

ISA Slots :

1 - Serial Card
2 - 286xpres Accelerator
3 - Roland MIF-IPC-A w/ Roland MPU-401 & Roland MT-32
4 - Adlib Music Synthesizer Card or Creative Game Blaster Card
5 - ADP-50L 16-bit IDE Controller

I feel no particular need to go 100% Tandy, but the floppy drives come from, if not manufactured by, Tandy.  I used to have a 20MB Tandy Hardcard, but the drive was very noisy and soon died.  So, in my only concession to modern hardware, I have a 1.0GB Compact Flash card mounted instead.   Unfortunately, the ADP card, which supports 16-bit IDE drives on an 8-bit bus, can only utilize 504MB of that due to the infamous limitations of the straight INT 13h/ATA addressing it uses.  This limitation is independent of any DOS limitations.  Compact Flash cards are virtually IDE devices, requiring only a passive pin converter to work with an IDE port.  The ADP card is a bit finicky about which CF drives it will boot, having not been designed for that.  The Board does not use IRQs or DMAs.  Two drives can be used for a total of 1008MB. The ADP board relies on memory mapped I/O, not port mapped I/O, so it should be faster than, say an XT-IDE card.  (The XT-IDE card with a 2.0 and above BIOS eliminates virtually all hard drive barriers, but even MS-DOS 6.22 and Windows 95 pre-OSR2 only support physical disks up to 8GB).  I may also be able to use a Trantor T-130B 8-bit SCSI interface card but that requires a separate SCSI-IDE bridge.  On the plus side, it does support and can boot up to 1GB storage devices.  However, the Trantor will freeze if it writes to a hard disk using an 8088 CPU.  A V20 CPU works with it.

Tandy MS-DOS 3.2, like all DOS versions 3.0-3.3, allows a primary DOS partition of only 32MB.  Support for extended partitions was added and standardized in DOS 3.3.  Tandy MS-DOS 3.2 does support up to three other DOS partitions on the drive (up to 32MB each), but it requires loading a driver in config.sys on startup and is non-standard.  Ultimately I chose MS-DOS 5.00 for its features (edit mainly) and it uses less conventional memory and hard disk space than DOS 6.22.  Also, while DOS 3.3's fdisk supports an extended partition up to 736MB in size, it has to be divided into 32MB logical drives from D:-Z:.  DOS 4-6 supports a primary partition of up to 2GB, all of which is the C: drive.  So MS-DOS 5.00 with a few additions from Tandy DOS (the Mode command, a device driver or two) works just fine.  If games start complaining about lack of free RAM (only 624KB is available before DOS due to sharing with the video), then I may have to go back to 3.3.

What kind of games would be played on this machine?  Well, all the important PC originals from 1981-1990. I will include any game whose maximum resolution was 320x200x16 and supports Tandy graphics or supports the Tandy sound chip for music and/or effects that does not support an Adlib, Sound Blaster, Roland MT-32 or Game Blaster.  Some examples include :

Thexder - Although the game supports an EGA 640x200x16 mode, which is appropriate considering its Japanese origins on the PC-88, it supports Tandy Sound for its music (all of two pieces).  Sound effects are PC Speaker only.

Secret of the Silver Blades, Champions of Krynn & Death Knights of Krynn - All support Adlib music, but if you select Adlib you get PC Speaker sound effects.  Tandy gives better sound effects than the speaker. Music only tends to be in the introduction to those games.

Games that require an EGA card and do not support Tandy, like Commander Keen, Duke Nukem & Sorcerian) are not going to be on this machine.  Similarly, games with a VGA version and an EGA/Tandy version aren't going to be either, unless the EGA version came out first (Indy 3, Monkey Island).  Nor would games that support a high resolution color EGA mode (Thexder II - Fire Hawk, SimCity, Zeliard, Silpheed) and sound cards.  In short, if there is no real benefit from running the game on a Tandy instead of an IBM PC or clone, then it has no real use in this machine.

The other hardware should be fairly obvious.  The Sound Blaster will see little use for its digitized sound and none for its midi or gameport capabilities.  Its there because I wanted an Adlib and a Game Blaster in one card.  The Roland is the ideal setup, nothing more need be said about it.  Chiefly only Sierra's games would have put it to any real use (custom sounds).

The 286xpress Accelerator requires a little explanation.  This device is an ISA card that can be used in a Tandy 1000, 1000A or 1000SX.  It has an 80286 CPU running at 7.16MHz and 8KB of cache.  It has a ribbon cable running from the card's daughterboard to the 8088 CPU socket on the motherboard.  It has a spare socket for a 80286 running at 4.77MHz.  The 8088 is plugged into the daughterboard.  This board does nothing unless activated when DOS boots either by a program loaded in autoexec.bat or a device driver in config.sys.  So it will not interfere with PC booter programs expecting 8088 speeds.  You can turn the cache off for better compatibility with programs.  With cache off, the system is just a little faster or slower than the system running at 7.16MHz on the 8088.  With the cache on, it is almost as fast as a Tandy TX or IBM PC AT @ 8MHz.  While an TX provides a serial port (freeing up a precious slot) and CPU upgrades fit into the slot (freeing up another slot), even at its slow speed it should still run faster than the SX at its fast speed.  So for older games that run like they are on amphetamines unless the CPU is an 8088 running at 4.77MHz,  it just isn't as good a choice.

Things to watch out for :

The RCA composite video output hues are somewhat different compared with the IBM PC in CGA modes, causing the colors displayed, compared to the IBM colors, are off.  For example, in Winnie the Pooh in the Hundred Acre Wood, Pooh appears in brown on an IBM and blue on the Tandy.  You can try to use the tint control on your monitor or TV to adjust the colors, but most TV monitors only allow a shift between red to green, which is not enough to make the colors accurate.  A composite monitor designed for computer use may allow a greater range of adjustment.  I believe this is present throughout the Tandy 1000s that have composite color output.  One game, Indianapolis 500 - The Simulation, by Electronic Arts actually allows the player to select an IBM or a Tandy palette in composite color mode, allowing the proper colors to be displayed with either type of machine.  If you use a standard CGA card in the machine, you should be able to get a more accurate IBM color.

The RCA audio output is not turned on by default.  (The Tandy 1000/1000A suffers from a similar problem, the EX, HX, TX and later models do not) The default is for all sound to go through the internal speaker.  Some programs like Maniac Mansion and Zak McKracken & the Alien Mindbenders fail to recognize that the SX is a little different and do not turn the audio output on.  A program called tdyspkr.com can be used in your autoexec.bat to turn the output on to the RCA out and/or off to the internal PC Speaker.

The default 80-column text mode on the Tandy annoyingly uses 225 lines.  IBM uses a 200 line text mode.  All graphics modes in these machines use 200 lines.  In order to get a proper aspect ratio with the graphics modes, the vertical size control has to be set almost to the point where the graphics are almost hidden by the monitor bezel.  When you return to the text mode, this winds up cutting off either the top, bottom or both lines of the display.  Use Tandy MS-DOS 3.2 mode.com command : mode 200, to fix this.  This does not work in the TL machines.  You can use the Tandy mode command in a later, non-Tandy DOS.

Tandy floppy disk drives require a ribbon cable without a twist!  They also require setting jumpers or switches on the drives to tell the machine which is drive A and which is drive B.  On an IBM PC, both drives are set to DS1, and the twist turns the drive at the end of the cable to DS0.  If you are using a modern 1.44MB drive in these systems, they are generally soldered to DS1, so they will be the B drive.  5.25" drives should always allow you to set DS0 or DS1.  But one of the great things about a Tandy is that they allow you to boot from the B drive by pressing the F3 key at startup.  If you have a standard "universal" floppy cable (with 3x pin connectors and 2x card connectors), you have to untwist the cable by prying off the end connectors, flipping the wires around, then snapping the connectors back on again.  Tandy did not support high density drives until the RLX and TL/3, but you can use most 1.44MB floppy drives with double density/720KB media.

The EX and SX are the last Tandy 1000s that does not use the floppy connector port to power the drives.  The HX, TX and all later Tandys, (inlcuding the SX's replacement, the SL), do run power through the drive cable.  If you are using floppy drives on a Tandy 1000 system that do not correspond to Tandy's power-in-drive cable pinouts, you must cut holes in pins 3, 5, 7, 9, 11 and 29, 31, 33 for any portion of the cable going to the regular drive.  I used an Xacto knife and a pair of clippers to do the trick, and only small holes are needed.  Tandy did this themselves with their cables so an individual could connect a standard 5.25" drive into an empty bay.

In the TL/SL/RL series, there is a way to disable the Tandy joysticks and use an IBM joystick adapter.  On the early Tandys, there is no way, you you have to use Tandy joysticks.  Tandy used the same joysticks for the TSR-80 Color Computer and the 1000 series.   They come in three varieties : the one-button (cheap) black non-centering Joystick, the two-button Kraft-style Deluxe Joystick, and the flight simulator pistol grip joystick (four buttons, only two usable).  You can also use a Color Mouse (one-button) or Deluxe Color Mouse (two-buttons) in a joystick port and a special driver.  The Deluxe Joystick is virtually identical to the Kraft IBM PC joystick or the IBM PCjr. stick, and can be either set to self-centering or or free floating in one or both axes.  There are some subtle differences in the control interfaces between the PC and Tandy joysticks which may manifest themselves in compatibility issues with older games.

Now, while you could use a Tandy Color Computer mouse, this is not an ideal method because of the attention the CPU must spend on the reading the joystick ports.  This can slow the PC down.  A much better alternative is to use a serial mouse, especially as serial mice are easy to find.  So are 8-bit serial cards.  Serial cards use IRQs to get the CPU's attention so excess CPU time is not wasted in polling the serial controller's I/O ports.  You will need to use an 8250B based serial card, which is typically what 8-bit cards use.  I always use ctmouse as a driver as does virtually every other vintage computing enthusiast.  Its compatibility is excellent and it only uses 3K of precious memory.  In the SX there is no serial port, Tandy fixed this in the TX by replacing the useless Light Pen port with a serial port.  (Some games, like the Gold Box games referred to above, do not support using a mouse with Tandy graphics).

Using a printer requires a special adapter cable.  For some reason, probably TSR-80 and old-style Centronics printer compatibility, Tandy used card edge printer port on all 1000s until the RL, RLX and TL/3.  The ribbon cable would have a card edge connector on one end and a Centronics port on the other end.  Fortunately, building a compatible cable should not be a problem, especially if you are connecting it to an IBM compatible printer.  One thing to note is that all card edge printer ports are unidrectional and devices that use the port for data transfer in (like a Backpack CD-ROM drive or a parallel port ZIP drive) will not work, even in nybble mode.

Games and programs requiring BASIC may be an issue if they require ROM BASIC.  ROM BASIC is virtually unique to IBM PCs and PS/2s of the 1980s, and even highly regarded compatibles like the Compaq Portable failed to run programs that required it.  Tandy DOS comes with GW-BASIC, which incorporates the BASIC that would otherwise be in ROM and supports the Tandy graphics and sound capabilities.  GW-BASIC may work for some games.

The Tandy 1000SX has two speeds, the default 7.16MHz and the 4.77MHz speed.  The latter speed is for compatibility for PC software that was only intended to be run on an IBM PC or XT.  Pressing F4 at boot will put the computer into slow mode, which is great for PC booters.  The commands mode fast and mode slow can be used in DOS to switch back and forth.  Also useful is F1 for mono mode and F2 for TV mode to kill the color text or to make the text more legible on a TV.

With my Compact Flash card, the only noise from the system is from the Power Supply fan.  The internal speaker is a large and loud 3" cone, even bigger than the 2.25" cone of the IBM PCs.  PC speaker sound can be output to the RCA audio out.  If you have a Sound Blaster Pro, which has a 2-pin PC Speaker input, you can connect the header which would otherwise connect to the internal speaker.  This allows you to output PC Speaker and Tandy 1000 sound to speakers without having to deal with the RCA port issue and being able to directly control the sound volume.

The Sound Blaster 1.0-2.0 all use DMA1 and do not play nicely with the PSSJ sound chip in the TL/SL/RL, which also uses DMA1.  Lockups and freezes are commonplace when digital sound is played.  The SX does not have a PSSJ chip, so the issue is not present.  However, I have a Central Point Software Option Board, which requires DMA1 in a Tandy system (it can share DMA2 in an IBM system).  So if that is installed, the Sound Blaster may not play nicely with it.

The Tandy keyboard is a funny thing.  It has 90 keys, and it is much more compatible with the IBM keyboard layout than it first appears.  Since an IBM 83 and 84 key keyboard used the numberpad for directional keys, use can use the Tandy's if the dedicated cursor keys are not working in the game.  The small shift keys are not much fun, there is no separate * key, the Alt key is in a funny place, and there is no scroll lock equilavent (use Alt Break).  Beware the Hold key, it will seem like the machine has frozen until it is pressed again.  Its nice that the Num and Caps Lock keys light up, which did not on an IBM PC or XT.  The \ key is also less than ideally placed.  The fat enter key is far superior to the IBM 83-key keyboard.  However, the IBM 83-key keyboard is probably the most solid and clicky keyboard I have ever typed on.  By comparison, the Tandy keyboard is mushy and prone to registering a keypress with only the slightest pressure.  It does not use rubber dome keys, it has springs in the keys, but still the action leaves much to be desired.  PC-compatible keyboards do not work on the Tandy 1000s prior to the TL/SL, but there was an adapter from Tandy that would allow a PC keyboard to work.  The Northgate Omnikey keyboards are also compatible with a special cable (which you may have to make yourself).

The SX and TX are the first Tandys that allow their graphics to be disabled if an EGA or VGA board is installed.  (The EX and HX can as well, but require upgrade cards with the PLUS adapter).  There is a special program that improves the detection of these cards in Tandy 1000s.  An MDA or Hercules compatible card should be installable in any Tandy 1000 except perhaps the 1000 and 1000A.  You can even install a CGA card in the SX, but some games may detect a Tandy 1000 machine and set their graphics to use the Tandy Graphics Adapter, requiring you to remove it.

On the SX, adding a math coprocessor is as easy as installing it into the empty socket and removing a jumper.  The machine came with 384K and was upgradable to 640K by installing eight 256x1 RAM chips into the empty sockets by the drive cage and removing another jumper.  There are four switches.  Switch 1 is useful if you have a MDA/Hercules card, switch 2 for hard drive controllers that are hard wired to IRQ2, switch 3 and 4 disable IRQ6 and IRQ7, respectively.

The last issues which must be addressed relate to the expansion slots.  Original Tandy 1000s did not come provide -5v to the expansion bus.  Sound cards like the Sound Blaster 2.0 require this voltage, as do many VGA adapters.  The SX has the voltage on the bus, so this should no longer be an issue on the later machines (except for the EX and HX, which also do not have this voltage on the PLUS expansion port).  More concerning is that fact that only 10" boards or shorter will fit inside any Tandy 1000 case.  The Roland LAPC-I, for example, will not fit, so I used a bare MPU-401 interface box with a small card.  Nor will most EMS memory boards.  Hard cards may be difficult to come by that will fit.

Tandy 1000s are supremely easy to open, all you need to do is to unscrew two screws from the front or the side and pull the cover forward.  Working inside the first generation models is not quite so easy, due to the disk drive cage and the screws used to hold the expansion slots in place.  Inside, the screws are all of the hex nut, standard screwdriver types, no Phillips head screws.  I use a hex nut on a flexible screw driver handle to get at the screws, and it works pretty well.  The expansion slot screws are a nightmare because they are so small and covered a bit by the back plastic piece.

In late 1986, the SX was released in its 2x5.25" drive version for $1,199.00.  A similarly configured PC or XT, which did not come with a printer adapter or a graphics adapter, would have cost much more and not have been as much fun.  Like the PCjr, it supports 160x200x16, 320x200x16, and 640x200x4.  (I think only Deskmate ever supported the last resolution).  Unlike the PCjr., it has register level compatibility with CGA, whereas the PCjr. has only BIOS level compatibility.  Also, while the PCjr. and the Tandy 1000 support the PC Speaker sound generation, the PCjr. only has a piezo tweeter, while the 1000s have the biggest PC Speaker cone I have ever seen in a compatible.  This means that games that tweak the speaker, like Access Software's Realsound games, will sound far superior on the Tandy than the PCjr.  The Tandy 1000 does not require device drivers to support more than 128KB, unlike the PCjr.  256KB and greater booter games will work on the former but not the latter.  Many games use these graphics and sound capabilities to give great improvements over competing systems.  There are several games that support Tandy but not EGA graphics and games that support Tandy sound but not sound cards or midi devices.

PCjr. specific software (almost all of which was released by IBM) may not run on the Tandy or support Tandy graphics and sound.  King's Quest and Touchdown Football (PCjr. versions) will not work in anything other than a Tandy 1000 with 128KB of RAM.  Fortunately there are Tandy versions available of these games.  The near mythical M.U.L.E. port IBM PC was alleged to take advantage of PCjr features but really only supports CGA and PC Speaker sound (but it runs on the jr.).  Cartridge software, even when dumped, will not work because it expects to find itself in the D000 and E000 segments.

Unfortunately, the SX requires the 286xpress accelerator board to play those games of the late 80s that run slowly on 8088 machines.  The 286xpress is not an easy find as it was very expensive back in the day.  Also, finding an ADP-50L is not easy either, as it was a niche product.  A fast hard drive is an absolute necessity with these machines.  If you cannot find a 286xpress accelerator, then I would definitely recommend a Tandy 1000 TX instead, which has an 8MHz 80286 processor.  It is the last system to be truly Tandy 1000 compatible, as the later systems use a PC compatible keyboard and lose composite output.

Sunday, June 26, 2011

Evolutionary Issues of Sierra's SCI Games

When Sierra first released its adventure games using its Sierra Creative Interpreter its hardware support was limited at first.

SCI0 Games:
King's Quest IV: The Perils of Rosella
Leisure Suit Larry Goes Looking for Love (in Several Wrong Places)
Police Quest II: The Vengeance
Space Quest III: The Pirates of Pestulon
Hoyle's Official Book of Games: Volume 1
Hero's Quest: So You Want to Be a Hero
Leisure Suit Larry 3: Passionate Patti in Pursuit of the Pulsating Pectorals
The Colonel's Bequest
Codename: Iceman
Conquests of Camelot: The Search for the Grail
Hoyle's Official Book of Games: Volume 2
Mixed-Up Mother Goose
King's Quest I: Quest for the Crown
Jones in the Fast Lane


In King's Quest IV, Police Quest II and Leisure Suit Larry 2, the first games released using this system, the hardware support was limited.  SCI0 games all use a 320x200 resolution with 16 colors.

The text parsers used in these games generally responded to simple commands such as "open door" "look building" and "talk man".  Sometimes the parsers would expect a more complex command.  One innovation over AGI was that typing paused the action.  The text box did not take up the bottom portion of the screen, leaving more room for graphics.  Drop down menus were standard for these games.

Graphics supported were CGA, EGA/VGA, IBM PS/2 Models 25 & 30 and Tandy 1000.  PCjr. Graphics was not yet supported, nor was the Hercules Graphics Card.

CGA - CGA was supported for a surprisingly long time, all SCI0 and some 16-color SCI1 games have CGA drivers.  CGA was not the ideal choice, and Sierra always used a recoloring algorithm to downsample the native 16-color graphics into 4 or 2 color graphics.  The first 4-color drivers used the Red/Green/Brown palette, but later drivers used the unofficial Cyan/Red/White palette.  2-color drivers frequently used gray as the foreground color, but blue is also available as a choice.  Composite color was never intentionally supported in SCI.

EGA/VGA - Since the VGA offered almost 100% compatibility with the EGA, this is usually the option people chose.  Sierra did not take advantage of the VGA's palette abilities, nor did it use EGA features that would break compatibility with VGA cards.

IBM PS2 Models 25 & 30 - This utilizes the MCGA in these computers to show proper 16-color graphics.  Since MCGA did not have a 320x200x16 mode, it uses the 320x200x256 mode without any extra palette features.  Since this mode is compatible with VGA adapters, there is no harm in selecting this on a VGA system. It does not check the BIOS for the specific model of computer.

Tandy 1000 - By SCI, Sierra had no longer provided any special reason to use a Tandy 1000, except as shown below.  This mode does not require more RAM than other graphics modes.

Sound Support was initially limited to the IBM PC or Compatible Speaker, PCjr./Tandy Programmable Sound Generator, Ad Lib Music Synthesizer Card, Roland MT-32 Sound Module and IBM Music Feature Card.

Ad Lib - I am not sure whether Sierra was the first PC game developer to support the card, but its support really helped support sales of PC sound cards.  Sierra sold it in its Catalogs.

Roland MT-32 - Unlike the previous device, I am sure that Sierra was the first PC game developer to support this device.  It was rather expensive when first supported and required both the module and a Roland MPU-401 ISA interface card.  Although possessed by a minority of game players, this device is what received the best support.

IBM Music Feature Card - I am sure that Sierra was the only PC game developer to support this ISA sound card.  A non-Roland MPU-401 compatible midi interface coupled with the equivalent of a Yamaha FB-01 sound module onboard, Sierra's support for this card was never high its priority list.

Sierra's SCI games supported IBM or Tandy keyboards, a joystick and a mouse.  Before the mouse-driven icon interface, joystick support was important.  Mouse support in SCI0 games merely offered another way to control your avatar and was generally not particularly useful.  Still, mouse support was not ubiquitous in those days and a mouse driver had to be loaded in DOS beforehand.  Sierra was forward thinking enough to allow Tandy TL/SL/RL users to use IBM keyboards, because they did not use the 90-key Keyboard of the older Tandy 1000s.

Now for individual observations for certain games :

King's Quest IV - An absolutely huge PC game when it was released in September, 1988.  Originally came on nine 360K disks, far more than any other PC game of the time.  This game does not use custom patches for the MT-32.  The early releases of this game used slightly different sound drivers than later games.  As such, sound drivers for later games cannot be used with this game.

Leisure Suit Larry 2 - Like King's Quest IV, the early releases of this game used slightly different sound drivers than later games.  As such, sound drivers for later games cannot be used with this game.  Also, the early releases had an Ad Lib driver which played the music at a noticeably higher pitch than later versions.  This game is the first to use custom patches, and all other SCI0-SCI1 games, except for the next one, used custom patches.

Police Quest II - This game does not use custom patches for the MT-32.  First game with Hercules Graphics Card support and official IBM PCjr. Graphics support.  Unlike all other graphics modes, PCjr. requires 640KB, which was not officially supported on the PCjr.

Space Quest III - First game to support digitized speech and sound effects.  At the time, the only hardware which was supported on was the Tandy TL/SL/RL PSSJ sound chip.  Also added support for the Casiotone MT-540 and CT-460 sound synthesizers.  Later the CSM-1 sound module was officially supported, but can still use these drivers.  This still required a Roland MPU-401 interface.

Eventually games supported the compatible Roland MT-100, CM-32L, CM-64 modules.  However, unless the driver claims CM-64 support, there will be unwanted sound effects being played on the CM-32P portion of that device because the earlier driver is sending Ad Lib data on channels 11-16.  If you have a CM-64 or CM-500, you can copy a driver from a later game to the earlier game, except if you are playing the early versions of KQ4 or LSL2.

Creative Labs Creative Music System/Game Blaster Card began to be supported.  In the Game Blaster box drivers were available for all games, including KQ4 and LSL2.  You can use a later driver with an earlier game except for the early versions of KQ4 or LSL2.  The Game Blaster, like the Roland devices, supports stereo sound.  Too bad the music sounds pretty weak.  This will work on the Sound Blaster 1.0 or an upgraded Sound Blaster 1.5 or 2.0.

Sierra also officially began supporting the Yamaha FB-01 sound module, attached to a Roland MPU-401 interface card.  This driver will work for earlier games that support the IBM Music Feature Card except the early versions of KQ4 and LSL2.  Eventually, Sierra stopped shipping IBM Music Feature/Yamaha FB-01 drivers with their games, and support could only be found by downloading custom patches on Sierra's BBS.  Some patches may have been lost.

While all SCI0 games have support for the Game Blaster one way or another, they may not have support for the Casio modules, so copying over the driver will not necessarily work.

Hero's Quest - Notable for two reasons.  First, as the name sounded like Milton Bradley's Hero Quest, Sierra changed the name of the series to Quest for Glory in later releases of this game.  Second, this game allowed the use of a mouse click to function as a look [object] command for what was clicked on.  Hotkeys were available for "ask about", which was frequently used.

In SCI0 releases, Sierra almost always included both 5.25" and 3.5" disks in the box.  Later budget releases would nix one or the other, and when Sierra released SCI1 games, it ended this policy.

Sierra was one of the first companies that had a TUI install program.  To install an AGI game, one had to type "installh c:".  To install an SCI game, one had to type "install" and follow the menus and insert the disks.

King's Quest 1 EGA/VGA - Introduced support for the Sound Blaster card, giving a second option to hear digitized sound effects.  This driver could be used for Space Quest III for non-Tandy machine owners.  This game had some real differences from the original AGI version.

Mixed Up Mother Goose - Obviously one of Roberta Williams' favorite games, Sierra released this game quite often.  There was an AGI version, a 16-color SCI0 version, a 256-color SCI1 version, a CD-ROM version of the 256-color version and an SVGA version that had a Windows executable.

Hoyle's Official Book of Games - Showing that the SCI engine was more versatile than text parser adventure games, these were collections of card games (Volumes I, II and Hoyle Classic Card Games).  SCI would be used for puzzle games (Dr. Brain series) and board games (Jones in the Fast Lane, Hoyle's Book of Games Volume III).

SCI1 Games:
Quest for Glory II: Trial by Fire
Hoyle's Official Book of Games: Volume 3
King's Quest V: Absence Makes the Heart Go Yonder!
Leisure Suit Larry in the Land of the Lounge Lizards
Space Quest IV: Roger Wilco and the Time Rippers
Mixed-Up Mother Goose
Leisure Suit Larry 5: Passionate Patti Does a Little Undercover Work
EcoQuest: The Search for Cetus
Jones in the Fast Lane (CD-ROM version)
Mixed-up Fairy Tales
Police Quest III: The Kindred
Space Quest I: The Sarien Encounter
Conquests of the Longbow: The Legend of Robin Hood
Castle of Dr. Brain

When Sierra transitioned to the SCI1 system, it began to narrow its horizons.  Separate 16-color and 256-color releases were released, with the former generally coming on double density media and the latter on high density media.  The 16-color versions used graphics converted from the 256-color originals.

Quest for Glory II - Although this looks and functions like an SCI0 game, it uses the SCI1 engine.  Its interpreter is compatible with other 16-color SCI1 games, even though they use point-n-click interfaces instead of the mouse interface.

All games after Quest for Glory II used a mouse point-and-click interface, and the mouse was the ideal method of control.  The second mouse button could be used to cycle through icons.

Space Quest I, Quest for Glory I, Police Quest I & Leisure Suit Larry 1 - Although Sierra apparently received negative comments from many fans about disrespecting their classic games by selling remakes, Sierra continued undaunted for each of the first games in their series.  Quest for Glory was the last game in this series, and supported General Midi as the optimal music device instead of the MT-32.

Graphics wise, the SCI0 games supported 256-color VGA and gray scale VGA.  The grayscale driver was better for people who played these games on gray scale VGA monitors, which could display only 64 shades of gray.  Tandy graphics were still supported on the 16-color versions, but those games would play very slowly in most Tandy 1000 machines.

Sound wise, the SCI0 games had full support for the Sound Blaster and soon supported Mediavision's Pro Audio Spectrum.  Many of the SCI0 games would support stereo OPL2 output on the Pro Audio Spectrum, which was unique to that card.  People who owned a Sound Blaster Pro or Pro Audio Spectrum 16 were out of luck.  The Adlib card had one OPL2 chip, which supported 9 FM synthesis instrument channels or 6 instrument channels with 5 percussion channels.  The latter is what Sierra used.  While the two OPL2 chips of the Pro Audio Spectrum offered double the number of channels, Sierra games did not support extra channels, it just sent some existing OPL2 channels to the left chip and some to the right chip.  Games also supported the IBM PS/1 Audio/Joystick Card, which was an upgrade that plugged only into the IBM 286-based PS/1 Models 2011 and 2121.

Joysticks were still supported, but trying to play any of these games without a mouse was foolish.  Tandy keyboards were also still supported.  This series also introduced Expanded, Extended and XMS memory support which could speed up game play.  (Extended Memory and XMS Memory are very similar, and usually XMS Memory would be used.  Extended Memory should be available if an eXtended Memory Manager (HIMEM.SYS) was not loaded in the CONFIG.SYS).

Eventually, Sierra started supplying drivers that would allow the user to use their Sound Blaster or Pro Audio Spectrum for digital sound effects and the MT-32 for music, giving the user the best of both worlds.  The Disney Sound Source began being supported for digitized sound, and Music and Speech would be separated in the install program.

Leisure Suit Larry 5 - The only Sierra game with support for the extra sound effects of the LAPC-1/CM-32L.  Many other Sierra games will occasionally produce the incorrect sound if not played back on a rev 0 MT-32 (no headphone jack).

This was the first time that CD-ROM technology was used.  Jones and King's Quest V use it, and also support natively being run in Windows 3.x.

Kings Quest V - CD version loses its MT-32 soundtrack in the Windows executable and uses an inferior General Midi composition.  Windows 3.x was not particularly well-suited to the MT-32.

SCI1.1 Games:
EcoQuest: The Search for Cetus (disk version 1.1, CD-ROM version)
EcoQuest II: Lost Secret of the Rainforest
Freddy Pharkas: Frontier Pharmacist
The Island of Dr. Brain
King's Quest VI: Heir Today, Gone Tomorrow
Laura Bow: The Dagger of Amon Ra
Leisure Suit Larry 6: Shape Up or Slip Out!
Mixed-Up Mother Goose
Pepper's Adventures in Time
Police Quest: In Pursuit of the Death Angel
Quest for Glory I: So You Want to Be a Hero
Quest for Glory III: Wages of War
Space Quest IV: Roger Wilco and the Time Rippers (CD-ROM version)
Space Quest V: The Next Mutation

SCI1.1 introduced more subtle changes.  For these games, General Midi began to supplant the venerable MT-32.  Police Quest I and Lara Bow 2 were the last games with MT-32 optimized sound tracks, other games using this interpreter supply a generic set of patches that remap the MT-32 to the General Midi patch standard.  Except as indicated in the last sentence, the Roland SC-55 and compatibles were the devices upon which the music sounded best.  Tandy Keyboard support is eliminated.

More games would be released on CD-ROM, including King's Quest VI, Lara Bow 2, Freddy Pharkas and Leisure Suit Larry 6.  In almost every case, these releases occurred subsequent to the floppy releases.  Older SCI1 games like Space Quest IV and Mixed Up Mother Goose would have CD-ROM releases with SCI1.1.

King's Quest VI - Displayed in a 640x480 graphics resolution in the CD-ROM version using the Windows executable.  However, this is only noticeable in the character dialog portraits.  The 320x200 graphics for the backgrounds and sprites are kept, stretched in a non-optimal manner.

Leisure Suit Larry 6 had a Low Resolution only CD-ROM release using SCI1.1.  A high resolution release using SCI2 would follow.

Graphics wise, separate 16-color versions were no longer available, so a dithering EGA driver was provided instead.  New speech support included the Mediavision Thunderboard, the Pro Audio Spectrum 16 and the Windows Sound System.  The Sound Blaster Pro and 16 were eventually supported for higher quality digitized sound, but there was no separate option in the install program.  The game would detect the card using the SET BLASTER variable in the autoexec.bat.

At this stage, Sierra was heavily promoting CD-ROM versions of its titles, but they would be released after the disk versions.  The key addition of the CD-ROM was the inclusion of voice acting in games which had previously been text-only for lack of space.  However, like early motion picture talkies, Sierra's initial efforts were not always impressive.  In KQ5, SQ4, LB2, EQ1, Jones, and Mother Goose, Sierra's staffers provided the voices and the results are often cringe-inducing.  In KQ6 and LSL6, they used professional voice actors.

I have occasionally come across a game with Gravis Ultrasound driver for music and speech.  I do not believe that the work involved in getting the GUS to work is worth it.

16-bit digitized sound is supported using the Media Vision Pro Audio Spectrum 16 or Windows Sound System drivers in DOS, but for a Sound Blaster, even a 16, the sound would be 8-bit only unless you used the AUDBLAST.DRV driver from the Freddy Pharkas or Leisure Suit Larry 6 CD.

SCI2 Games:
Gabriel Knight: Sins of the Fathers
The Beast Within: A Gabriel Knight Mystery
King's Quest VII: The Princeless Bride
Leisure Suit Larry 6: Shape Up or Slip Out! (hi-res CD-ROM version)
Mixed-Up Mother Goose Deluxe
Phantasmagoria
Police Quest: Open Season
Quest for Glory IV: Shadows of Darkness
Shivers
Space Quest 6: The Spinal Frontier
Torin's Passage

SCI2 drastically reduces the available options.  Gone is support for EGA or joysticks.  These games require Extended Memory.  They use a DPMI extender to access it.  All were released on CD-ROM, and only Gabriel Knight, Police Quest IV and Quest for Glory IV had floppy releases.  At this point, there was little reason to use the floppies.

Police Quest IV - Supports 640x480 VESA graphics with the floppy install, all the other SCI2 games support high resolution graphics with their CD-ROM version only.  The floppy version allows the player to choose VGA or VESA, the CD-ROM auto-detects whether the video card supports VESA and selects that mode if it does.  Leisure Suit Larry 6 works in the same way.

Gabriel Knight 1 - The first Sierra CD game with actual "name & face" voice actors.  Previous Sierra efforts had the production team voice the characters, (KQ5, SQ4, LB2) or had professional voice actors (KQ6, QG4), but this was the first game where actors known (Tim Curry, Mark Hamill, Michael Dorn, Efrem Zimbalist, Jr.) or would become known (Leah Remini, Rocky Carroll) by face and name to the general public were used.  Never again would a Sierra SCI game feature so prominent a cast.

Quest for Glory IV is the only game using the SCI2 interpreter that does not support high-resolution graphics.

Gabriel Knight 2 and Phantasmagoria were the only SCI2 games to use FMV, coming on a whopping 6 and 7 CD-ROMs, respectively.  The former and Torin's Passage has digitized music, no more Adlib or MIDI support.

All CD-ROM only games support 640x480x256 graphics only.  This meant that they required SVGA/VESA capabilities, since straight VGA cannot support this.

King's Quest VII was originally only released for Windows 3.x.  It also could take the greatest hard drive space of any DOS SCI game, 100MB, if installed with the full options.  Version 2.0 added DOS and Windows 95 compatibility.  Mixed Up Mother Goose Deluxe and Shivers were the first SCI games never released for DOS.

Support for the Sound Blaster AWE32 for music was added.

Two observations about the gameplay of many of SCI2-3 games is that they no longer had that "death on every screen" aspect of earlier games.  While you could die in most of these games, there was an option to replay the sequence and hopefully avoid death.  This spared the player from the failure to save the game every minute.  In addition to lethal nature of earlier games, dead-end situations abounded.  These tended to be reduced in these titles.

The second observation is the elimination of icons.  Games began using just a cursor, which would function as a look, use, walk, talk and get command depending on the context.  Sometimes a command menu would be displayed.  The cursor would often highlight on an object on the screen that could be interacted with.

SCI3 Games:
Leisure Suit Larry: Love for Sail!
Lighthouse: The Dark Being
Phantasmagoria II: A Puzzle of Flesh
RAMA

The final version of SCI, SCI3, required a VESA compatible graphics card and were all released on CD and do not support Midi.

Phantasmagoria only supported Windows out of the box, Sierra released a patch so it could be used in DOS.  DOS only supports 256 colors, Windows supports 16-bit (65535) color.  

I originally included Shivers 2 on the list, but it apparently is not a true SCI game and it has no DOS support.

Lists of all known SCI games are available here : http://wiki.scummvm.org/index.php/Sierra_Game_Versions#SCI_Games