Video Potpourri II

Sometimes, one needs to discuss related subjects that do not by themselves warrant a full blog entry.  Hence the video potpourri series, in which I can talk about aspects of display technology.

I.  Composite Artifact Color Emulation

Composite artifact color emulation has been around for a long time.  Unfortunately, in many cases it just isn't very good at trying to replicate the look of a composite monitor.  Simple schemes just assign a color arbitrarily to a group of two or four monochrome pixels.  Mainline SVN DOSBox tries to simulate CGA composite color as if it were a VGA mode.  The colors are reasonably accurate to the real IBM CGA cards, but the text color fringing is rather blocky.  There are custom builds that use filtering and 16-bit color to give a more subtle impression of the composite color, but it still looks much, much cleaner than the real image.  You can obtain a custom build with better composite color emulation here : http://www.vogons.org/viewtopic.php?f=41&t=12319&start=660#p501453

Restoring the Fluid Look to Analog Video

As we all know theatrical sound film releases are typically projected at 24 or 25 frames per second.  Film is a progressive medium where each film frame captures an image at a discrete point in time.  However, film must be developed before it can be exhibited and must handled by experienced technicians, making it a costly medium in which to produce artistic works.  To reduce flicker, a shutter in the camera would open or close twice for each frame.

Prior to the advent of television, celluloid film was the only commercial means to display visual moving images.  However, the introduction of wholly-electronic television broadcast and receiver systems meant a massive change.  TV broadcast cameras were able to achieve acceptable image quality by broadcasting images in an interlaced format.  A broadcast camera and a TV tube display images in a set number of lines, and the electron scanning beam inside the tube scans or displays each line sequentially, then returns and draws the next line.  (Think of a typewriter.)  When it gets to the bottom of the tube, it returns to the top of the tube and draws the next set of lines.

In order to allow the electron beam sufficient time to draw all the lines, interlacing was used.  In an interlaced format, "frames" become "fields". A field only captures the odd or the even lines of the TV camera lens.  After all the odd lines in the first field are captured, then all the even lines of the second field are captured.  In the NTSC countries, 59.94 color fields (formerly 60 fields for B&W NTSC) are captured each second.  In PAL and SECAM countries, 50 fields are captured each second.  When this is broadcast to a TV screen, the fields are displayed as they are captured.  The high number of displayed fields avoids flicker on the TV screen.

Nintendo Mini Mania Redux - The Classic Mini Family Computer

Nintendo has released another retro-themed surprise.  Back in July, Nintendo announced the NES Classic Edition/NES Mini, an emulation box containing 30 classic NES games.  Here is the original trailer for it :  https://www.youtube.com/watch?v=qAGVilt3Rls  I discussed it here :

http://nerdlypleasures.blogspot.com/2016/07/nes-classic-editionnes-mini-nintendos.html

Yesterday, Nintendo announced a Famicom version for the Japanese market.  Like the NES Mini, the "Classic Mini Family Computer" is a miniature replica of a Famicom with a power and a reset button.  It also has 30 games and will cost 5,980 Yen, which is close to the NES Mini's $59.99 price.  It is going to be released on the same day as the NES Mini, November 11, 2016.  While the official trailer is in Japanese, the visuals are self-explanatory :

Older Sci-Fi Shows in the HD Era

So, you want some of your classic sci-fi shows on Blu-ray?  How do they do that you may ask?  Well, in many cases it depends on when and where the show was created.

In the 1950s through the mid 1980s, U.S. science fiction TV was shot entirely on film.  Classic shows like The Twilight Zone, The Outer Limits, Star Trek, Night Gallery, Kolchak: the Night Stalker, The Six Million Dollar Man, Wonder Woman, Battlestar Galactica, The Incredible Hulk, Buck Rogers and V: The Series all had the Hollywood look.  Effects were done on film, practical where necessary, optical as required.

Then in 1986, Star Trek: The Next Generation started its seven year run.  This series initiated a revolution in special effects.  While live action was still caught on film, wholly special effects scenes depicting the Enterprise and the various ships and worlds it encounters would often be generated on video with the use of computer graphics imagery (CGI).  CGI would often make its way into the live action as well.  Unfortunately, these images would be constructed in standard definition.  This method of production continued for almost two decades, every Star Trek series (except the last season of Enterprise), Babylon 5, Farscape, Firefly, The X-Files, Hercules and Xena used this method.

Accessible Good Famicom Games

The Famicom had over 1,000 games released for it during its lifetime.  Hundreds of those games were never released outside of Japan, and there were only a few releases of Japanese games exclusively in Europe.  Of course, many, many of those games that never officially made it out of Japan are terrible, as were many games that did make it overseas.  In this post I am going to list many good Famicom cartridge games that were not released for the North American NES console.  Not all the games identified below are classics, but all have their virtues.  Famicom Disk System games have already been mostly covered elsewhere :

http://nerdlypleasures.blogspot.com/2016/04/worth-loading-times-famicom-disk-system.html

The first list is of games that are English-friendly.  These games do not use a lot of Japanese text and what text there is is not essential to completing the game.  Most of these games have translation patches as well.  Many tend to be simpler games, namely shooters and platformers :

Two Late Classic Apple II to PC Ports, Unalike in Dignity

Even though the Apple II was very long in its lifespan by the end of the 1980s, there was a fair bit of software still being released for it.  The Apple II was very strong in the educational market, computer labs across the United States had yet to upgrade to the PC platform.  The Apple II had many, many classic games.  Most of them were ported to the PC at some point, but by the end of the 1980s the number of A2-to-PC ports (that did not have the name Carmen Sandiego in the title) was dwindling.

Even so, two classics of the Apple II did make their way to the PC platform in the late 1980s and they are the subject of this blog entry.  The first is MECC's 1985 update of The Oregon Trail.  The second is Jordan Mechner's Prince of Persia, programmed on and released for the Apple IIe, IIc and IIgs in 1989.  MECC ported the Apple II version of The Oregon Trail to the IBM PC in 1988.  Mechner and Broderbund ported the Apple II version of Prince of Persia to the PC compatibles in 1990.

The Oregon Trail is the simpler game, in fact it was an update of an earlier version MECC made for the Apple II in 1980.  That version was mostly text-based and occasionally displayed simple wire-frame graphics and a little music.  Before personal computing, Oregon Trail was played on mainframes on a time-share basis.  But the 1985 Apple II version is undoubtedly the most popular version of the game.  The 1985 version requires 64KB of RAM on an Apple II.  This version was ported to the PC by MECC in 1988.  The PC port requires 512KB of RAM and at least a CGA card.

Prince of Persia is a spiritual successor to Mechner's Karateka, another big hit.  Both were published by Broderbund.  Prince of Persia takes the rotoscoped graphics and one on one combat of Karateka and combines them with running and jumping mechanics, obstacles, traps and triggers.  It requires 128KB of RAM and an Apple IIe capable of displaying double high resolution graphics, a IIc or a IIgs.  It only uses double high res graphics on the title screen and story text screens (four screens).  Mechner supervised the ports of the game to the IBM PC compatibles and the Amiga in 1990.  It supports CGA, Hercules, Tandy, EGA and VGA and a variety of sound cards and 512KB-640KB depending on the graphics mode.

When it came to porting these games to the PC, MECC did an outstanding job.  Broderbund and Mechner, not so much.

Recording the IBM PC Speaker's Sound

The PC Speaker was the first audio device that PCs used.  In some form or another, it is contained in almost every PC ever made.  In the original IBM PC, the Model 5150 released in 1981, the speaker was a distinct cone 2.25" in diameter.  And it was loud, but it had to be in order to compete with the noisy power supply fan and the seeking of the disk drives!  The tones it output were pure, and while they were rather harsh they were also clear.

However, eventually the PC Speaker began to shrink in size and eventually give way to the tiny piezoelectric tweeters that are just too quiet to do justice to any kind of complicated audio.  (You can blame IBM for putting the idea into other manufacturer's heads because the IBM PCjr., released in 1983, used a piezo tweeter for the PC Speaker.)

When emulators like DOSBox became mature, they could easily output basic PC Speaker audio.  Basic PC Speaker audio is essentially a square wave with a fixed volume level and a 16-but frequency selector.  They can have difficulty with the more complex sounds produced by Pulse Width Modulation, which essentially sends changes to the frequency of the square wave to the speaker faster than the speaker cone's driving circuitry was intended to handle.  This requires a much more rigorous emulation of the CPU, the timer and the "analog" characteristics of the audio generation.

Famciom vs. AV Famicom External - Internal Audio Mixing

There is a myth that the AV Famicom is too quiet when it mixes internal audio with external audio.  The myth goes that the external cartridge audio drowns out the internal audio from the console and gives an unbalanced and unfair impression of what the programmer intended the music and sound effects to sound like.  The conclusion is that an original Famicom, preferably an earlier model, is the ideal way to experience Famicom audio.  However, this conclusion is too simplistic and the internal/external mix is not as extreme on standard Nintendo Famicoms and AV Famicoms as one may be led to believe.

Of course Famicom audio has its own problems.  The first problem is that genuine Famicom audio is encoded into RF and decoded in a TV.  The baseline audio has a buzz and the output of the audio sounds like it was run through an oppressive low-pass filter.  The second problem is that playing a Famicom with its RF video and hardwired controllers is something of a chore.

I have made some recordings of several games which use Famicom expansion audio and internal Famicom audio.  The games in question are :

Zelda no Densetsu (Famicom Disk System, The Legend of Zelda)
Akumajou Densetsu (Konami VRC6, Castlevania III: Dracula's Curse)

More Keyboard Adapters : The Tandy 1000 Keyboard to Tandy 1000 TL or SL

The earlier Tandy 1000s, the 1000, 1000A, 1000 SX and 1000 TX came with a 90-key Tandy Keyboard.  The Tandy 1000 EX and HX had the 90-key Tandy Keyboard built in.  This keyboard uses its own communications protocol and timing and is not compatible with an IBM PC, XT or AT or their clones.  This keyboard uses an 8-pin DIN plug.

The later Tandy 1000s from the TL and SL onward came with 101-key keyboards.  These keyboards, called the Tandy Enhanced Keyboard, were an autoswitching keyboard that could work in an IBM PC, XT, AT or their clones.  This keyboard uses a 5-pin DIN plug and do not work in an earlier Tandy 1000.

In the technical reference manuals for the TL and SL, which are the last Tandy technical reference manuals available online, the keyboard controllers do mention Tandy 1000 Keyboard compatibility.  These computers have a 7-pin DIN connector even though an XT or AT keyboard only uses four pins.  The schematics indicate that the extra pins are used for Tandy 1000 keyboard-specific signals.

Pleasant Suprises : The Epson MGA Q205A

Sometime ago, I acquired an 8-bit ISA card called the Epson MGA Q205A.  I figured it was a CGA compatible card because it had one DE-9 female port and one RCA jack, which the standard CGA configuration.  The only unusual thing about the card was a two-position switch on the bracket plate.  The switch is labeled color/mono.  I couldn't find anything about the card in Total Hardware '99.  I noted that the card displays in color on startup instead of B&W on a color composite monitor, I figured the switch was there to turn it to B&W.  An IBM CGA displays in B&W on startup in an IBM PC or XT.

After testing the card out a bit, I was pleased that it gave composite colors reasonably close to an IBM CGA card.  I was also pleased that the card is less than 10", meaning it will fit inside a Tandy 1000 computer.  However, Trixter's CGA Compatibility Tester demonstrated that the CGA compatibility was weak when it came to the 6845 tests.  This is not particularly surprising when I determined that the card does not have a 6845 CRT Controller onboard.  Since I have three IBM CGA cards, the card rarely has surfaced in my thoughts.

Northgate Omnikey 101 vs. IBM Model M Keyboard

I have had the privilege of being lent a Northgate Omnikey 101 keyboard.  This keyboard is identical to the layout of my IBM Model M keyboards.  I am going to first identify the features of each keyboard and then give my impressions of the Northgate compared to the Model M.

Enclosure

Model M's use PBT plastic on the top and bottom enclosures, on the key caps and the key stems.  For this reason Model M do not yellow through exposure to ultraviolet light.  On the other hand, PBT can be somewhat brittle and it is not a rare thing to see cracked keycaps on a Model M.  Because keycaps come off very easily, it is often the case that you will find a keyboard for sale with one or more missing.  The enclosure is held together with hex screws requiring a long-barreled 7/32" driver to access.  Later Model Ms, mostly made by Lexmark and Unicomp, often have drainage holes cut into the bottom half of the enclosure for liquid spills, but the IBM-made keyboards rarely have them.

Famicom and NES Expansions and Peripherals

Famicom Peripheral List

Devices that Plug into the Famicom Cartridge Slot

Nintendo Famicom Disk System

• 199 Official Licensed Games + Prize Cards (and unlicensed games, copying programs etc.)
• Comes with a disk drive and a RAM Expansion.

The RAM Expansion is inserted into the cartridge slot and the cable from the RAM Expansion is connected to the rear of the disk drive.

The Northgate Omnikey to Tandy 1000 SX & TX Keyboard Adapter

The Tandy 1000 computers, more specifically the early Tandy 1000s, had many good features, graphics, sound, expansion, performance, integrated peripherals.  To save development costs, Tandy imported some of its designs from prior, non-IBM PC compatible computers.  The Tandy 1000 card edge printer port can be traced back to the TRS-80.  The Tandy 1000 joystick ports came straight from the Tandy Color Computer.  And finally, the Tandy 1000 keyboard is the same keyboard used in Tandy's MS-DOS (but not IBM PC) compatible Tandy 2000.

The 90-key Tandy 1000 keyboard is not exactly a pleasure to use.  Its layout is cramped and awkward, its keys are mushy and there is no tactile feedback.  Compared to the IBM PC or IBM PC AT keyboard, it feels cheap.  Typing mistakes are frequent with this keyboard.  It has some odd key omissions.  There is no Scroll Lock, and while there is a separate Home key, there is no separate End, Page Up, Page Down, +, -, or * keys.  The shift keys are too small.  While it does have F11 and F12, software made during the Tandy 1000 (except by Tandy) lifespan rarely used these keys.

Finally, the Tandy 1000 has the dreaded Hold and Print keys.  Both keys are next to important keys like Enter, Alt and Num Lock,  The Hold key acts like a true Pause key, everything is frozen until you hit the Hold key again.  People who do not know or forget how the Hold key works may think their computer has crashed.  However, the really evil key is the Print key.  Press this key twice and, unless you have a printer attached to your computer, your computer will freeze as it vainly tries to print what you are typing on the screen. Your computer will appear to freeze.  IBM avoided this issue by assigning the function to Ctrl+Print Screen.

RetroUSB AVS vs. Analogue Nt mini - Comparison of the Enthusiast FPGA NES Clones

Until now, any kind of accurate Nintendo NES or Famicom console had to use Nintendo's CPU and/or PPU chips, whether that console was manufactured by Nintendo, Sharp or anyone else.  While the idea of implementing a NES on an FPGA was an idea with a long history, only this year are products finally making it to market.  Here I am going to compare the features of the two announced FPGA NES implementations, the RetroUSB AVS and the Analogue Interactive Nt mini.

Console	AVS	Nt mini
Producer	RetroUSB	Analogue, LLC
Hardware Designer	Brian Parker “bunnyboy”	Kevin Horton “kevtris”
FPGA Type	Xilnix Spartan 6 XC6SLX9	Altera Cyclone V
Included	HDMI, USB Cable (mini-to-standard), Power Supply	HDMI, USB, 8Bitdo NES 30 Wireless Controller, Retro Receiver, Power Supply
Outputs	HDMI, USB	HDMI, Analog Video, RCA Stereo
Inputs	4 x NES Controller Ports, 1 x Famicom Expansion Port	4 x NES Controller Ports, 1 x Famicom Expansion Port, Microphone Input
Upgrade	USB Port	SD Card Slot
Resolution Support	720p	480p, 720p, 1080p (HDMI) 240p (analog sources only)
Video Display Support	HDMI	Composite, S-Video, Component, RGB, HDMI
Buttons	Separate Power & Reset	Combined Power & Reset
Unique Special Features	NA Scoreboard, Built-in Game Genie, Turbo-in-Software	Scalers, Famicom Expansion Audio Generation, Audio Visualizer, Famicom Microphone, NES Zapper/Famicom Gun Support (Analog video only), R.O.B/Family Robot Support (Analog video only)
Price	$185.00	$449.00
Availability	September, 2016	January, 2017

Boulder Dash - PC Speed and Joysticks

Boulder Dash was originally released for the IBM PC and PCjr. in 1984 by First Star Software.  The disk included two separate executables, one for the IBM PC and one for the IBM PCjr.  The disk was a PC booter.

The IBM PC executable is serviceable but not particularly impressive.  There is a distinct lack of animation on the title screen and for the amoeba tiles.  There is also no color-cycling effect for the diamonds.   It is debatable whether the game really uses composite color graphics.  Sound effects are weak even by PC speaker standards.

The IBM PCjr executable, on the other hand, is much, much more impressive.  It uses the 3-voice PCjr. chip for music and sound effects.  It supports 16-color graphics with full animation and color cycling.  Despite the PCjr. being slower than the PC, it does not suffer from a lot of slowdown, despite the extra effort.  Compare these pairs of screenshots from the PC and PCjr. executables :

Boulder Dash on the Atari 2600 - Beginning or Continuing a Long Journey

BD2600 - Title Screen

In late 2011, a new homebrew cartridge was announced for the Atari 2600.  This would be a port of Boulder Dash, the classic computer game originally developed on the Atari 800 home computer by Pieter Liepa and Chris Gray.  Their game was bought by First Star Software, which published it for the Atari 8-bit, Commodore 64, Apple II and IBM PC & PCjr. computers in 1984 as well as for the Colecovision.   FSS also published the sequel, Boulder Dash II : Rockford's Revenge and Boulder Dash Construction Kit.  FSS's other well-known game series is the Spy vs. Spy games.

Boulder Dash was very popular, with the game being ported officially or unofficially to many different platforms.  The Amstrad CPC, BBC Micro, Epoch Super Cassette Vision, Game Boy, MSX, NES, PC-8801 and ZX Spectrum all received officially licensed ports. Except for a period from around 1991 to 2001, there has rarely been a year gone by without a release or re-release of Boulder Dash in some officially licensed form.  Today it can be purchased on mobile platforms.

The PC Joystick to Tandy 1000 Joystick Port Adapter

IBM PC-compatible joysticks using the DA-15 connector came in all shapes and sizes.  Some have a hat switch, some have a throttle wheel, and many are quite durable.  The CH Flightstick Pro is among my favorite PC joysticks.  Its large enough to fit in my hand, has easy movement and feels very precise.

Unfortunately, Tandy 1000 users do not have many options, thanks to the 6-pin DIN connector the 1000 line used.    The official Tandy joystick line consists of the miserable black box joystick with the single button and non-self centering stick, the Deluxe Joystick which fixes those issues but is still rather boxy and uncomfortable, and the Pistol Stick Joystick, which has a handle but is really basic.  Not many third parties released joysticks with the Tandy plug, but in this blog article, I will tell you how to adapt any standard PC-style joystick to work in a Tandy 1000 joystick port.

The Generic DOS PC - A Critique of LGR's 486 Build

If you wanted to build a DOS PC, what would you build?  The answer depends in no small part on what you expect it to run.  Do you want a system that can run the oldest games?  In that case you will probably want an IBM PC, XT or one of the earlier Tandy 1000 series systems.  Perhaps even a PCjr. or a Compaq Portable?  But those systems are often running PC Booters as much as they are running true DOS games.  Fast forward a couple of years and you get into EGA and VGA systems.  Now you are dealing with higher speed 286s, 386s and 486s.  Even though many of the more speed sensitive games will fail to run on these systems, the classic DOS era is at hand.  But suppose you want something with 3-D acceleration and high resolution color in mind.  Then you are looking at Pentium systems and sharing drive space with Windows 95 games.  Duke Nukem 3D, Fallout, Magic Carpet 2 require more than what most 486s will give.

I would suggest that most people probably received their first introduction to IBM compatible PCs and DOS in the early 1990s, "When VGA Was King."  In those days, then-young adults like myself were in awe at the beautiful graphics of the King's Quest games, addicting world-building simulations like Civilization and complex role-playing of the Ultimas.  We saved our allowances to buy a Sound Blaster card because systems did not come with sound cards as a standard feature until well into the mid-90s.  We looked eagerly at the new CD-ROM technology, waiting for it to drop in price and salivated at The 7th Guest and Myst (and found out that cutting edge technology seldom lives up to the hype).  PCs had something to offer that our NES, SNES and Genesis consoles could not.

Building a DOS system often addresses that era of early 90s gaming with the ability to reach somewhat back to the late 80s and forward into the mid 90s.  Building vintage computer systems has become something of a niche hobby, but now one with very dedicated members.  My own humble writings here and elsewhere may have made some small contribution to this phenomenon.  But when someone like Lazy Game Reviews decides to post a system build video, it will get a great deal of attention.  With almost 400K Youtube subscribers and videos easily ratcheting 100K views within a short period of time, he is sufficiently successful on that he does not need a day job.  Although far many more people watch his Sims videos than his retro-computing videos, there is enough overlap that his message reaches many more people than anyone else I know of who regularly covers retro-PC topics.


Here is his first video : https://www.youtube.com/watch?v=fbjYkPKRm-8
And here is his followup video : https://www.youtube.com/watch?v=g15J44xB2zU

The Tandy 1000 Digital Joystick Adapter

IBM PCs and compatibles had an analog joystick interface.  The Tandy Color Computer and clones like the Dragon 32/64 computers also had an analog joystick interface.  Inside an PC or CoCo joystick were a pair of potentiometers.  The chief difference between the two interfaces is how the potentiometers were connected.  PC sticks used the potentiometers as variable resistors, wiring two of the three terminals, one of which to +5v and the middle would be connected to the interface's input.  CoCo sticks used the potentiometers as voltage dividers, where all three terminals would be connected, one outer terminal to +5v, one outer terminal to ground and the middle terminal would be connected to the interface's input.

In the early days of home computers, a joystick could be used for more than just playing games.  It could function as a cursor controller like a mouse, which was useful for drawing programs.  It could also be used for flight simulators, where the analog control could be appreciated.  Most home computer games from the 1980s that support a joystick were ported or derived or inspired by the popular home console and arcade games of the time.  Games like Pac-Man, Pitfall and Space Invaders did not really need an analog stick, they usually used digital joysticks.  When platforming games like Super Mario Bros and Prince of Persia became popular, they often or exclusively used digital gamepads.

Who Needs a Sound Blaster? - Deficiencies with Early Emulators

It is the accepted conventional wisdom that if you want to play DOS games from the DOS era (1988-1996) you will need some form of Sound Blaster card or compatible.  However, not everyone could afford a Sound Blaster card or felt the need to upgrade to a Sound Blaster from their Adlib or even their PC Speaker.

What was compatible with a Sound Blaster?  In the first few years of the line, not much.  Software that supported the Adlib or (sometimes) the Game Blaster were upwards compatible with the Sound Blaster, but it did not work the other way around.  Early competitors like the original Mediavision Pro Audio Spectrum and Covox Sound Master II were not compatible with the Sound Blaster outside Adlib support.  MIDI-based devices like the Roland MT-32 and Roland Sound Canvas were never Sound Blaster or even Adlib compatible.

Sound Blaster clones like the Thunderboard and the Aztech Sound Galaxy series either reverse engineered the Sound Blaster or used Creative Labs-supplied chips.  The Pro Audio Spectrum Plus/ 16/Studio contained a Thunderboard, so its compatibility with software supporting the Sound Blaster 2.0 or lower was high.  Later cards like the Yamaha YMF-71x series also had high Sound Blaster Pro 2.0 compatibility (but would not play all Duke Nukem II ADPCM sound effects, see below).  OEMs like Dell, Compaq and Gateway often included no-name cards with Crystal or ESS chips that provided workable Sound Blaster compatibility.