Is there a Doctor in the Game Console? - The Venus Turbo Doctor 6M

Taiwan may or may not have been the birthplace of commercial video game piracy, but it certainly has a strong claim to have been its nursery.  When video games skyrocketed in popularity in Southeastern Asia with the Famicom, it seemed as through the entire island of Taiwan wanted to cash in on the efforts of the Japanese.  Taiwan was the first source of unlicensed Famicom clones and pirate cartridges.  But cartridges were expensive to make, even for Taiwan fabs and the larger games were not very profitable to clone.  Then Nintendo handed the pirates a gift, the Famicom Disk System, and as it turned out the gift kept on giving.  While copying FDS games was child's play for the organized pirates, they saw in the FDS an opportunity to pirate to go beyond games originally released on disk. They created RAM cartridges, hardware devices that worked with the Famicom and the Disk System to permit cartridge games put on disk to work.  In this blog entry, I will describe my personal experiences with one such device, the Venus Turbo Game Doctor 6M.

Early Efforts at Online Interaction on Nintendo Consoles

We tend to think that Nintendo consoles first entered the online arena with the GameCube, its Modem and Broadband Adapters and Phantasy Star Online.  In the west, this is the case, but every Nintendo home and portable console (except that hunk of eye-straining junk called the Virtual Boy) has had some way to access the non-local world.  Sometimes these methods were first party supported, sometimes third-party exclusives and there was even an unlicensed publisher or two in the mix.  This blog entry will give an overview of the subject.  I will describe briefly each device or method, As this blog entry's purpose is not meant to give a comprehensive review of each of these devices.  I will include links for more information to sites and videos with more information.  

Nintendo's 8-bit Obsession with Golf

Golf is popular in most parts of the world with any concentration of wealth.  It is rather popular in Japan, at least for those who can afford to play it.  Green fees and club memberships are extremely pricey in Japan, so it may not be any surprise that many people who enjoy the game may have to turn to less expensive alternatives to get 18 holes in.  Most video game systems have a golf game, or something intended to resemble golf, released for them.  When Nintendo was releasing early titles for its Famicom, a golf game was a natural addition to its sports library.  But Nintendo kept revisiting the sport with its 8-bit systems, so let's explore how its implementation of golf evolved throughout the 8-bit lifespan.

Exciting Developments for NES ROMs

When it comes to the NES, everybody at one point or another has emulated the NES.  NES emulation has been around for a long time and has improved so much that often the experience of playing a game on an emulator is indistinguishable from playing the game on real hardware (accounting for video improvements via emulation.)  But NES emulation is continually evolving as we find more games to dump and understand better the hardware found inside previously-dumped games.  In this blog post let me share some recent developments regarding NES ROMs.

Investigating the Games on the NES, Famicom and SNES Classic Editions

Nintendo's latest efforts to "cash in" on its retro properties, the NES Classic Edition and the SNES Classic Edition, have gone very well.  The hardware is inexpensive to make and the games, for the most, part, are held in high regard.  The consoles sell very well, sometimes too well.  All across the three major markets, they were in high demand at launch.  One interesting thing about these devices for me is the software included on these devices.  These are emulator boxes and they run ROMs, just like the Virtual Console for the Wii U and Wii and previous releases for the GameCube.  Let's see what kind of ROMs they use.

Famicom Expansion Audio Overview

The Famicom was constructed with a feature which was not available to the NES.  The Famicom always sent its internal audio to the cartridge port.  For most games, the audio was sent back to the system without modification.   26 (of 1,054) licensed Famicom games contained hardware that could produce additional music and mix it in with the internal audio.  In this article, let's take a look at the methods that were used and the games that used them.

Worth the Loading Times? - Famicom Disk System to Cartridge Conversions Worth Playing

The Famicom Disk System may offer games that saved to disk and enhanced music and sound effects, but it came at a cost.  The disks can fail, the drives' belts can snap and the disk system introduced loading times to the Famicom platform.  With devices like the FDSStick, the first two issues have been eliminated but the last issue remains.  Here I am going to list all Famicom disk system games with a later port to NES or Famicom cartridge and determine whether the extra features (if any) are worth the drawback of putting up with loading times.

First, here is the list of games :

FDS Title / NES Tile (if Different)	What Is Saved?	FDS Audio Sound Effects	FDS Audio Music	Disk Sides
Akumajō Dracula / Castlevania	3 Games	N	N	2
Bio Miracle Bokutte Upa (Unreleased for NES)	Does not Save	N	Y	2
Bubble Bobble	Highest Level	N	N	2
Dr. Chaos	3 Games	N	N	2
Dracula II: Noroi no Fūin / Castlevania II: Simon's Quest	3 Games	N	Y	2
Exciting Basketball / Double Dribble	Does not Save	Y	Y	2
Final Command: Akai Yōsai / Jackal	Does not Save	N	N	2
Green Beret / Rush 'n Attack	Does not Save	N	N	2
Gun.Smoke	Does not Save	N	N	2
Gyruss	Does not Save	N	Y	2
Hao-kun no Fushigi na Tabi / Mystery Quest	3 Games	Y	Y	2
Hikari Shinwa: Palthena no Kagami / Kid Icarus	3 Games	Y	Y	2
Ice Hockey	Does not Save	N	N	1
Karate Champ	Does not Save	N	N	2
Konami Ice Hockey / Blades of Steel	Does not Save	N	N	2
Zelda no Densetsu / The Legend of Zelda	3 Games	Y	Y	2
Metroid	3 Games	Y	Y	2
Moero Twinbee: Cinnamon Hakase wo Sukue! / Stinger	Does not Save	N	N	2
Nazo no Kabe: Block Kuzushi / Crackout	3 Games	N	N	2
Pro Wrestling: Famicom Wrestling Association	Does not Save	N	N	1
Roger Rabbit / The Bugs Bunny Crazy Castle	Does not Save	N	N	2
Section Z	3 Games	N	N	2
The Legend of Zelda 2: Link no Bōken / Zelda II: The Adventure of Link	3 Games	Y	Y	2
Tobidase Daisakusen / 3-D Battles of the World Runner	Does not Save	N	Y	2
Volleyball	Does not Save	N	N	1
Yume Kōjō: Doki Doki Panic / Super Mario Bros. 2	Worlds Beaten by Each Character	Y	Y	2
Zanac	Does not Save	N	N	1

Bold means that there is in-game Famicom Disk System Expansion Audio music, which is rare.  

Swaps and Loads: Famicom Disk System Games Least Appreciated Development

The Famicom Disk System always had loading times for its games.  In fact, the Legend of Zelda was released as a launch title and used both sides of the disk.  The game required the user to flip the disk at a certain point and would load new data at certain times.  Over time, the loads and swaps became more frequent.  When you consider the major advantages of the FDS, namely the sound channel and no need for passwords, consider the tradeoffs over their cartridge releases in the form of disk swaps and load times.  Whether running a game off real disks, an disk emulator like FDSLOADR or the FDSStick or a NES emulator (Nestopia probably has the best FDS sound emulation), you will have to face these inconveniences.  Below let me give some examples of games that were ported to the NES and their loading and swapping requirements.

Zelda no Densetsu - The Hyrule Fantasy
Yume Koujou! Doki Doki Panic

These titles are the easiest to deal with when it comes to swaps and loads.  Both require you to swap to side B at the title screen.  Zelda will load each Underworld dungeon level as you enter it and the Overworld when you exit.  DDP will load each time you start a new world (but not a new level) and the incomplete ending.    Zelda saves to side B, but DDP saves to side A, requiring a swap when you want to save your game.  DDP also requires a swap to side A when you want to see the real ending.

Metroid
Palutena no Kagami

Metroid and Palutena require you to swap to side B after you start a game.  Metroid will load each of the five areas as you go up or down the elevators.  It will require you to swap back to side A for the ending and for saving.  Because Metroid saves to both sides of the disk, the swap instances take upwards of a minute.

Palutena has short loads before and after every boss palace level.  When entering Medusa's level, 4-1, you will have to swap to side A.  There is a final load after you defeat Medusa.

Akumajou Dracula

In all versions of this game, there is a load before every level.  The last level where Dracula is the boss has a second load between stages 17 and 18.  However, different versions of this game handle their swaps at different points in the game.  The same saves to side A.

In v1.0 and v1.1 of the game, you will swap to side B when you start the second level.  You swap back to side A after you beat Dracula to view the ending.  In v1.2, you will swap to side B when you start the first level.  When you reach stage 18 in v1.2, you will swap back to side A.  I believe that Konami was trying to give more experienced players a break in v1.2 by not requiring them to swap when they try to beat Dracula for the umpteenth time.

Legend of Zelda 2 - Link no Bouken
Dracula II: Noroi no Fuuin

These games win the prize for the most loads of any that were ported to the NES.  While both require you to swap to side B to start a game, they have many more loads.  The Legend of Zelda 2 has a load for each entrance to and exit from the eight towns and seven palaces.  Also, there is a load when you cross a land boundary.  There are four land boundaries in the game: Western Hyrule, Spectacle Rock,  Eastern Hyrule and Maze Island.  Finally, you must swap the disk to enter the Great Palace (the last palace) and there is a load for the ending but the disk swap does not occur until the credits roll.  The game mercifully lets you continue at the Great Palace if you lose all your lives (but not at previous Palaces), so you don't have to swap the disks again until you play a game from the main menu.

Similarly, Dracula II: Noroi no Fuuin has a load for every time you enter or exit one of the seven towns or the screen with one of the five Mansion entrances.  Even when you just want to walk on past the Mansion entrance, it is annoying because you have to put up with two loads!  If you get knocked back from a screen, you have to suffer through two loads.  If that was not bad enough, in the last half of the game there are frequent loads and swaps.  To give you an exact description of the loads and swaps, here is a plan of the last part of the game and the areas you must visit to complete the game in an efficient manner :

Town of Ondol - > Deborah Cliff - > Bodley Mansion - > Uta Lower Road 1 & 2 - > Debious Woods - > Joma Marsh 1 - > Laruba Mansion -> Joma Marsh 1 -> Debious Woods -> Uta Lower Road 1 & 2 -> Bodley Mansion -> Wicked Ditch -> Town of Doina -> North Bridge -> Dora Woods -> Town of Yomi -> Vrad Graveyard -> West Bridge -> Castlevania -> Ending -> Title Screen

 -> Loading
 -> Loading and Swap to Side A
 -> Loading and Swap to Side B

Before this sequence, you had only one swap to side B when you started a game.  There are nine loads and five disk swaps in a somewhat short period of the game map!  No wonder why even Japanese gamers appear to rate this game substantially lower than its predecessor or its sequel!

The FDSStick, a Compact Solution for all your Famicom Disk System Needs

The Famicom Disk System just was not a very reliable piece of hardware.  Between bit rot on the disks and drive belts that wear out quickly, today it is an error prone beast.  However, most of the work is done in the FDS RAM Adapter, the black box that fits into into the Famicom's cartridge slot.  Many Disk System enthusiasts, myself included, have long sought a method to use their FDS RAM Adapter without having to deal with the dodgy disks and flaky drives.  Since 2004, the only solution has been an FDSLoadr cable or find an incredibly rare copying device from back in the day.  The cable connects to a PC parallel port and the software is DOS only.  While it can read and write to disks or use the PC as the drive emulator, it is really speed sensitive and the cable is not easy to make because of the FDS connector.

Old FDSStick vs New FDSStick (with a penny for scale)

Many people have dreamed of a more convenient solution, so a NESDev forum regular named loopy stepped up in 2015 and designed a USB-based device that would allow you read and write disk images solid state media and let the FDS RAM Adapter or Twin Famicom read it like a regular disk.  He has called the product the FDSStick and has offered it for sale.  The price is ridiculously cheap for folks in the USA, a mere $11.99 plus $2.60 for shipping.  You can buy it here : 

http://3dscapture.com/fdsstick/

International customers order from TotoTek for $14.99 plus shipping here :

http://www.tototek.com/store/index.php?main_page=product_info&products_id=196

The FDSStick is about the size of a USB thumb drive, just a little thicker.  The first enclosures had a smooth rough matted finish.  This was my first experience with a 3-D printed object.  The enclosure does what it needs to, but if it represents the state of plastic construction, we have a long way to go before we abandon plastic injection molds and CNC machines.  The enclosure tends to pick up dirt and, like most 3-D printed objects, is not especially strong.  Not too long after the first batches, loopy switched to using injection molded cases, so the quality has been greatly improved and the finish is smooth.

The FDSStick has a USB plug on one end and a 12-pin cartridge edge on the other end which the FDS RAM Adapter cable plugs into.  The FDSStick is unusual for a device that interfaces with vintage computing equipment because it is completely hot swappable.  The USB end obviously has no issues with being inserted into a live computer or hub.  The FDS end can be inserted onto the end of the FDS RAM Adapter's cable when the Famicom is turned on.  The RAM Adapter cable was designed to plug into the Disk Drive when both the drive was plugged into a wall socket or running off batteries and the FDS RAM Adapter was plugged into a Famicom that is turned on.

Installing the FDSStick, Loading Games onto the FDSStick and Saving Games from the FDSStick

The FDSStick is easy to install and use.  First, you insert it into a spare USB port or hub (which does not need to be powered). The FDSStick will load its drivers automatically. I did not need to be in Test Mode to load the driver, apparently loopy has Windows Driver Signing privileges.  Click “Run Anyway” when Windows says it does not recognize the program.

There is a graphical user interface (GUI) program, FDSStick.exe to transfer disk images to and from the FDSStick.  You can download them it from http://3dscapture.com/fdsstick/  The program will automatically detect when the FDSStick is plugged into a USB port attached to the computer. The program is not particularly useful without the FDSStick, the GUI program will not load when FDSStick is not plugged into the computer.  As downloaded, the file name of the program will include the date of release.

FDSStick.exe allows you to load .fds images onto the FDSStick and save images from the FDSStick in .fds format.  It will also run images in the Game Doctor format, but unless you have a Game Doctor device, you probably will never encounter a Game Doctor image.  Running the GUI program with the FDSStick plugged in will update the firmware, which I highly recommend to everyone because the new firmware can add features and fix bugs.

The oldest version of FDSStick had 4 Megabits of rewriteable memory and can hold up to 8 disk sides on its flash memory at a time.  The second version FDSStick has 16 Megabits of rewriteable memory and can hold 32 disk sides on its flash memory at a time.  The third version of FDSStick has 128 Megabits of rewriteable memory and can hold 255 disk sides on its flash memory at a time.  The fourth version of FDSStick has 256 Megabits of rewritable memory and can hold 512 disk sides on its flash memory at a time.

If each game you want to load is only one-sided, you can load 512 games onto the current FDSStick. There are only 199 licensed FDS games, however some games have multiple versions.  There were many unlicensed games released for the FDS by companies like Hacker International.  However, if your games are two-sided, then you will be able to load no more than 256 games.  Only six four sided games were ever released.  You can mix and match games using different numbers of sides so long as the total number of disk sides does not go above the maximum number of disk sides supported by the version of FDSStick you have.

The program has a meter that will show how full the FDSStick will be when you write your images to the device.  When you have finished making your choices, click on write and it will quickly write the images to the FDSStick.  It will take less than a minute to write the maximum number of disk sides to the FDSStick. Saving the existing games to your PC can be done in the same tab, using the file name you used when you originally loaded the game.  You can also remove individual games from the FDSStick using the GUI without erasing the whole of the rewriteable memory.

The program can also load games stored on your PC with the PC Emu tab.  This is useful if you have an FDSStick with a small amount of rewritable memory, but the price for the most recent version is so reasonable that it is well worth an upgrade double dip.  You must connect your FDSStick to your PC using a USB cable extender to allow this to work.

Using the FDSStick with the FDS RAM Adapter and the Twin Famicom

When you insert your FDS RAM Adapter into your Famicom and turn the system on, you will see the Nintendo logo (or FAMICOM if you are using a Twin Famicom) with the Please Set Disk Card text. You can insert your FDSStick into the FDS RAM Adapter cable before or after you turn the system on. A menu will appear on the screen and you can select the game using your controller, just like with a PowerPak or EverDrive N8.  Unlike those flash carts, the FDSStick does not support subdirectories.  You may want to trim down the file names to no more than 28 characters so that the game's name will fit on the menu screen. Spaces count, but the extension does not.

FDSStick Game Menu 

Game images need the FDS file format 16-byte header to work with the FDSStick's internal storage.  When you load single-sided disk images, they must be exactly 65,516 bytes large.  Double-sided disk images must be 131,016 bytes large.  You may need to add one with a hex editor (if you are using the no-intro set).  The crucial thing the header tells the FDSStick is how many sides the game has.  Only byte 04 differs in any FDS header, it is either 01 for single sided disk games, 02 for double sided disk games and 04 for four sided disk games.

After the game loads, it may ask you to change disk sides.  If it asks you to change to side A, you always press the button once.  If it asks you to change to side B, you always press the button twice.  If you want to select a new game, turn the power off on the console and back on to return to the FDS menu.

It is much easier than it used to be for sure!  In the oldest firmwares, there was no menu on the FDS "Please Set Disk Card" screen.  You had to know the order in which the game was written to the FDSStick.  When the FDSStick was first released, you had to know which of the eight slots the disk image's side A was in.  Prior to the firmware update, you also had to remember the slot in which the game's side A and B were located.  You also had to use a Command Line Interface if you wanted to write more than one game to the FDSStick.  Now it is incredibly intuitive to use the FDSStick.  Don't get started on the dark ages of the pre-FDSStick era.

The Twin Famicom does not have a RAM Adapter or a cable to connect to the FDSStick.  This is not surprising because the whole point of the Twin Famicom was to combine the Famicom and Famicom Disk System in an all-in-one unit.  However. the Twin Famicom has a port on its underside that has the signals the FDSStick needs.  For an extra $4, you can buy an adapter for the Twin Famicom that will easily interface with this port, but you will need a cable from an FDS RAM Adapter or find a Nintendo Multi-Out connector with connections for 11 of the 12 pins.  See http://3dscapture.com/fdsstick/ for more details.

Reading and Writing Real Disks

The FDSStick can copy to or from FDS Disks using the FDS Drive using the Disk tab of the program.  However, there are two difficulties with putting disk images onto real disks.  First, the drive must not be protected or the protection must be bypassed.  FDS Drive protections are covered here :

http://famicomworld.com/workshop/tech/fds-power-board-modifications/

http://famicomworld.com/workshop/tech/famicom-disk-system-fd3206-write-mod/

Second, you will need to make a coupling cable or start soldering wires.  Both the disk drive and the FDSStick use a male end, so you will need a cable with female to female connectors.  You can do this if you had two spare FDS RAM Adapters to cannibalize, you can use a pair of Nintendo Multi-out cables or you can solder wires directly from the exposed Disk Drive Power Board PCB to the test points on the FDSStick PCB.  I would suggest the second option using cheap third party connectors.  You will need to cut, file or grind down the bump that keeps the cable going in the right side up in Multi-Out sockets.  I would suggest a dremel for this purpose or a file.

After you have a good fit, look here for instructions on how to solder the wires : http://3dscapture.com/fdsstick/

Once you have your cable, insert your disk into the drive, power up the drive, and connect your coupling cable to the drive and the FDSStick.  Connect the USB end to your PC and use fdsstick.exe to read from a disk or to write to a disk.  It will save the image in the FDS format, but unlike the images found in the TOSEC and No-Intro sets, it will preserve the 16-bit CRC bytes for each file on the image. Emulators had no use for the CRC bytes.  It should also preserve the exact number of Gap bytes between each file and before the beginning of the disk.  The exact number of Gap bytes is indicated by a terminating bit, which is not needed by emulation.  There may be some copy protected games that require this sort of information, but I am not aware of any.

Some games have a simple method of copy protection whereby they put files after the last file indicated in the file number block.  These files appear hidden and will not be transferred in a file by file transfer, but will if the dumper always dumps 65,500 bytes as loopy's should do.  When loopy's device loads FDS game images from TOSEC or No Intro from its internal storage, it calculates and adds CRC bytes and Gap termination bits for the FDS RAM Adapter.

If you have trouble reading and writing disks, look to the information in the later pages of this thread, for advice : http://forums.nesdev.com/viewtopic.php?f=9&t=12163  If your disk is damaged, not much can be done except to combine it with an undamaged disk from the No Intro or TOSEC sets.

Why Buy the FDSStick? 

I have been able to complete the following games from start to finish without issue using loopy's FDSStick :

Akumajou Dracula (Demon Castle Dracula/NES Castlevania)
Dracula II: Noroi no Fuuin (Dracula II: The Seal of the Curse/NES Castlevania II: Simon's Quest)
Hikari Shinwa: Palutena no Kagami (Myth of Light: The Mirror of Palutena/NES Kid Icarus)
Legend of Zelda 2: Link no Bouken (Legend of Zelda 2: Adventure of Link/NES Zelda II: The Adventure of Link)
Metroid
Yume Koujou: Doki Doki Panic (Dream Factory, Heart Pounding Panic/NES Super Mario Bros. 2)
Zelda no Densetsu: The Hyrule Fantasy (NES Legend of Zelda) (first and second quests)

I think that is a fair endorsement for this device. Everything else I have tried works without flaw, as long as you avoid corrupted images. If an image from the No-Intro set appears corrupt (like Palutena used to be in older sets), try one from the TOSEC set and vice versa.  Note that No-Intro will put a [b] next to working images because they have saves on the disk.  A disk with saves is impure, but I have figured out how to "purify" many FDS games : http://nerdlypleasures.blogspot.com/2015/06/cleaning-saved-information-from-famicom.html

One awesome feature of the FDSStick is that you can backup your saves.  When you beat any of the above games, you will not be able to see the ending unless you beat the game again.  Use an FDSStick to back up your game before you beat it and you can reload the fds image whenever you want to see an ending.

The currently available NES/Famicom flash carts just do not cut it when it comes to FDS emulation.  The NES PowerPak can fail with certain games and its sound emulation is sometimes off.  The EverDrive N8 is more reliable with games but you cannot pause a game when the game wants to change disk sides and the sound emulation is worse.  Even the mighty Hi-Def NES Mod and Analogue Nt will have notably "off" FDS sound.

The RAM Adapter, on the other hand, provides perfect sound.  It does not crash when given good images. FDS RAM Adapters can usually be had for $50 shipped.  It makes those FDSLoadr cables and Game Doctor devices thoroughly obsolete.  There are also other similar devices like the FDSemu (256Mbit) and the Magic Wild Card (uses microSD cards), but they are more expensive.  These are probably the best reasons why you should consider the FDSStick.

Cleaning Saved Information from Famicom Disk System Game Dumps

A lot of Famicom Disk System games save some information to disk.   Often this information may be custom levels designed with an in-game level editor, the top scores or the fastest times or the levels beaten.  The more ambitious adventure and RPG games would typically offer three save slots to store the player's progress during the game.  The use of magnetic media, the Disk Cards, allowed any Famicom Disk System game to save information to the disk.  When games are dumped, any information saved will come with them. While this will not diminish the playability of a game, it still cosmetically very unappealing to see "Diskdude" all over the high score lists or hacked games on the file select screen.

Unfortunately, for most games there is no way to restore the game to a pristine, never-played state within the game itself. I have always wanted a tool or utility that could take these disk images and do just that, but since none exists I decided to investigate the images and try to fix them myself. Restoring a Famicom Disk System game to a pristine state is often times more involved than just deleting or zeroing out the last file. The resulting disk image has to work after it has been "cleansed". I used Nestopia UE 1.46 and FDSExplorer 1.63 and my favorite hex editor.  A hex to decimal calculator will also come in handy.

Famicom Disk System games come on one or two disks.  A game on a single disk can use one or both sides of the disk, two disk games always use four sides.  The sides are labeled Side A and Side B.  The Disk System's drive was single sided, so the user had to physically eject the disk, remove it from the drive, turn it over and insert the disk.  The disk drive can automatically sense when a disk has been inserted and inform the rest of the system.  

A straight dump of each side of a Famicom Disk Card will have a size of exactly 65500 bytes.  Each subsequent disk side dump is appended to the previous side, so two disk side games will be 131,000 and four disk side games 262,000.   Modern Famicom Disk System game dumps use an .fds file extension.  They can come with an extra 16-byte header for emulators and flash carts.  This header looks like this :

46 44 53 1A 0x 00 00 00 00 00 00 00 00 00 00 00

x = number of disk sides, typically 1, 2 or 4.

The first three bytes show FDS in ASCII and the fourth byte is also used as the MS-DOS End of File byte.  The header is extremely basic and is designed to inform an emulator that the file loaded is a true FDS disk image and how many disk sides the game has.  While this could have been discerned by the file extension and file size, the FDS image format was created in the days of Nesticle, an MS-DOS based NES emulator.  MS-DOS files used 8.3 character/extension file names, so the likelihood that files could be confused was much greater.

Famicom Disk System games have a simple file system.  Each file on the disk has a name using up to eight characters, a file number (0-x), an ID number (ditto), a size (up to 32KB) and a type.  The three types are Nametable, CHR and PRG.  CHR stores graphics tiles, PRG stores code and the Nametable is always the first file on Side A and is used for the Copyright text at the beginning.  If the text is not exact, the disk will load no further.  Save games are always stored in a PRG type file.  

What made this much easier was the fact that Famicom Disk System games always seem to save to the last file on a disk's side. Later in the Disk System's life, (1988) Nintendo used a new drive controller chip that limited the disk drive to writing only to the last file on a disk. The earlier convention became a rule. 

Sometimes the save file has an obvious name and is so small it could be nothing else, but for other games it is not so obvious. So the first thing I had to do was to observe which side was being written. Nestopia tells you when a disk is being read or written, so I just played until there was a save. Metroid was almost unique among the games I looked at because it saves information to both sides. 

Once I figured out which side was being saved, I opened the disk image in FDSExplorer and looked at the file. For games with three save slots, I simply deleted two and made a third with a file name that was easy to find like ABCDEFGH. With a little deductive reasoning (i.e. looking at the hex patterns and logical reasoning) I could figure out how the file could be corrected so that no save games would be present at startup. Dr. Chaos did not follow the typical rule about writing changes to all files after starting a new game, but its save file is really simple and my image came with one unused file.

On a couple of occasions, I discovered that my image was pristine but the game actually created a file once there was saving. FDSExplorer makes it easy to delete the last file in these cases, but you have to verify that the game creates a file before you delete it. I made it a point to alter no more bytes than was necessary to make the game appear to look pristine. Whether it would actually correspond byte by byte to a pristine, error-less dump of a sealed Disk Card is an issue that may never be known for some games, but for other games the changes are so obvious and minor that it can hardly be doubted that this is how they should have appeared. 

Nintendo, for its own first-party games, eventually began to store a backup of a pristine save file elsewhere on the disk.  That way, if the save file became corrupted after a write, the game could try to restore the save file so the user could continue to play the game.  Hikari Shinwa - Palutena no Kagami is an example of such a game.

Some games will allow you to restore the game to a pristine state via an in-game function.  They are detailed below.

Here is a list of the games and what I did to make them "pure". 

Akumajou Dracula (all versions) (Konami, 1986)

Information Saved - Three slots, last stage completed and number of continues

Fix : Side A - Zero out last file

NES/Famicom Port : Castlevania/Akumajou Dracula

All Night Nippon Super Mario Bros. (Nintendo 1986)

Information Saved - Number of times you have beaten the game

Fix : Side A - Zero out last file

NES/Famicom Original : Super Mario Bros.

Bubble Bobble (Taito, 1987)

Information Saved - Allows you to select a starting level up to the last level you completed

Fix : Side A - Game creates a save file when you save your level progress, delete file with FDS Explorer

NES Port : Bubble Bobble

Clu Clu Land - Welcome to New Clu Clu Land (Nintendo, 1992)

Information Saved - High scores

Fix : Side A - In the last file, this pattern must repeat ten times : 14 EF EF EF 24 00 00 00

NES/Famicom Connection : Clu Clu Land

Dr. Chaos (Pony Canon, 1987)

Information Saved - Three slots, progress through game

Fix : Side A - Zero out last file, except for the last eight bytes, should say DR.CHAOS in ASCII

NES Port : Dr. Chaos (NTSC Only)

Dracula II - Noroi no Fuuin (Konami, 1987)

Information Saved - Allows you to select a starting level up to the last level you completedtime taken in game

Fix : Side A - Zero out last file

NES Port : Castlevania II : Simon's Quest

Eggerland (HAL Laboratory, 1987)

Information Saved - Rooms completed

Fix : Side B - Start a new game, commit suicide until you see the Game Over screen, then save.

NES/Famicom Connection : Adventures of Lolo 1, 2 & 3, Eggerland - Meikyuu no Fukkatsu

Eggerland - Souzouhe no Tabidachi (HAL Laboratory, 1988)

Information Saved - Allows you to select a starting level up to the last level you completed, saves levels you build with the construction editor in the game.

Fix : Side B - Zero out the last byte in the last file and remove all tiles for all construction levels using the in-game utility, then save.

NES/Famicom Connection : Adventures of Lolo 1, 2 & 3, Eggerland - Meikyuu no Fukkatsu

Hao-Kun no Fushigina Tabi (DOG, 1987)

Information Saved - Three slots, progress through game

Fix : Side A - Delete all three save files in the main menu, then create file one. Immediately close the FDS image in Nestopia. Replace the first seven bytes in the last file with 00 5F 5F 5F 5F 5F 5F.

NES Port : Mystery Quest (NTSC Only)

Hikari Shinwa - Palutena no Kagami (Nintendo, 1986)

Information Saved - Three slots, progress through game, time taken to beat game, high scores

Fix : Side A - Copy hex from REG BACK and paste into REG.SAVE

NES Port : Kid Icarus

Kaettekita Mario Bros. (Nintendo, 1988)

Information Saved - Name, age and gender of players controlling Mario and Luigi, High Scores

Fix : Side A - Rename characters to the default, use hiragana for Mario and Luigi, set the ages to 00 and the gender to male (おとこ). Mario is まりお and Luigi is るいーじ in Nintendo's preferred hiragana spelling.

Side B - Copy over all bytes in file 9 to file 10

NES Port : Mario Bros. Classic Series (PAL Only)

NES/Famicom Connection : Mario Bros.

Knight Move (Nintendo, 1990)

Information Saved - High Scores

Fix : Side A - Save file is split into four sections of 48 bytes. The game uses the first and last section for saving the scores, so copy the second or third section to the first and fourth section. 

NES/Famicom Connection : Tetris/Tetris (designed by Alexey Pajitnov)

Legend of Zelda 2, The - Link no Bouken (Nintendo, 1987)

Information Saved - Three slots, progress through game, number of deaths

Fix : Side A - Kill all save files on the file select screen, the game will reset each slot as after it is killed. The No-Intro dumps for the Legend of Zelda 2 for the FDS will not allow you to see or take any items like heart containers and magic jars for their first save slot.  This can be easily fixed by entering a new name for the first save slot, then killing the the name and entering it again.  

NES Port : Zelda II -  The Adventure of Link

Metroid (all versions) (Nintendo, 1986)

Information Saved - Three slots, progress through game, time taken in game, ending earned for last game.

Fix : Side B - Create a new character for file one, then start the game. Immediately close the FDS image in Nestopia. Do the same for file two and three. Do NOT save the game. This causes the game to reset the save information for the world for the three files because the game will write to side B when you create a new character.  Side A - Overwrite the first three bytes with 80 and the next forty eight bytes with FF. Zero out the rest of the file. This deletes character information.

NES Port : Metroid

Nazo no Kabe - Block Kuzushi (Konami, 1986)

Information Saved - Allows you to select a starting level up to the last level you completed

Fix : Side A - Delete all three save files, then create file one. Start the game, lose all your balls, then save and quit. In the last file, replace the first sixteen bytes with the second sixteen bytes. These two sets of bytes should be identical to the third set of sixteen bytes. The last sixteen bytes of the file should be 00.

NES Port : Crackout (PAL Only)

Nazo no Murasamejou (Nintendo, 1986)

Information Saved - Three slots, progress through game

Fix : Side A - Kill all save files on the file select screen, the game will reset each slot as after it is killed.

NES/Famicom Connection : The Legend of Zelda/Zelda no Densetsu 1 - The Hyrule Fantasy (engine)

Section-Z (Capcom, 1987)

Information Saved - Three slots, progress through game

Fix : Side A - Delete all three character saves in the game menu, then create file one. Start the game, get killed, then save and quit. In the last file, replace the first twenty three bytes with the second twenty three bytes. These two sets of bytes should be identical to the third set of twenty three bytes. The last four bytes of the file should be 00.

NES Port : Section Z

Super Mario Bros. 2 (Nintendo 1986)

Information Saved - Number of times you have beaten the game

Fix : Side A - Zero out last file

NES/Famicom Connection : Super Mario Bros. 1, 3

Vs. Excitebike (Nintendo, 1988)

Information Saved - Race times and data for custom tracks 4-7 designed with built in construction editor.

Fix : Side A - Delete the last file

NES/Famicom Connection : Excitebike

Winter Games (Pony Canon, 1987)

Information Saved - Records for each event

Fix : Side B - Zero out last file

NES Port : Winter Games (NTSC Only)

Wrecking Crew (Nintendo, 1989)

Information Saved - Custom level designs for phases 1-4 designed with built in construction editor.

Fix : Side A - Delete all objects on each of the four phases ofthe design part, then save.

NES/Famicom Original : Wrecking Crew

Yume Koujou Doki Doki Panic (Nintendo/Fuji Television, 1987)

Information Saved - Worlds completed by each character.

Fix : Side A - Zero out first four bytes in last file

NES/Famicom Port : Super Mario Bros. 2/Super Mario Bros. USA

Zelda no Densetsu - The Hyrule Fantasy (Prototype and final) (Nintendo, 1986)

Information Saved - Three slots, progress through game, second quest, number of deaths

Fix : Side B - Kill all save files on the file select screen, the game will reset each slot as after it is killed.

NES/Famicom Port : The Legend of Zelda/Zelda no Densetsu 1 - The Hyrule Fantasy

Further notes :

There are many, many other FDS games that save information to disk.  I have only given a sample of the games which either have a NES port, are part of an NES series or substantially related to an NES game. Many Famicom Disk System games are Japanese-text heavy, which can make it more difficult to purify the image.

Nestopia does not save to the disk image by default, but can in its options menu. You should also change the option so that you can see the status Reading Disk/Writing Disk in Nestopia's status bar.  Always make backups when experimenting. Nestopia saves to an image when the image is closed or the user quits Nestopia. 

Unfortunately, FDSExplorer does not allow you to edit files inside a disk image directly, it is easiest to use a Hex Editor and search for the bytes you wish to alter. 

This list really only scratches the surface, but I wanted to focus on games that were ported in some way or form on or related to a NES cartridge. Since my Japanese is "a little rusty", I did not want to tackle the more Japanese text-heavy games.

The Famicom Disk System - Impact, Issues and Ports

Nintendo released the Family Computer (Famicom) on July 15, 1983 in Japan for a cost of 14,800 Yen.  Cartridges for the system typically cost 4,500-5,500 Yen.  On February 21, 1986, Nintendo released the Family Computer Disk System accessory at a cost of 15,000 Yen.  Disks with new games typically cost 2,600-3,400 Yen, but the cost to rewrite a game was only 500-600 Yen.  At the time, Nintendo heavily promoted this peripheral as the future of gaming as it saw it.

Nintendo focused its efforts on the disk system for quite a long time.  The last cartridge game it released for the Famicom before the disk system's release , Mach Rider, was released on November 21, 1985.  It did not release another cartridge for two years (Punch-Out!!, November 21, 1987) and only had released ten cartridge games by the end of 1991. By contrast, excluding ports and revisions of cartridge games, Nintendo released twenty-six FDS games during the same time period.

The actual situation with cartridges became more complex than Nintendo wanted.  While Nintendo was off in magnetic-media land, its third parties carried the disk-less console and developed new cartridge hardware to increase drastically the amount of ROM space available to the games.  While the Disk System was not Nintendo's greatest success, it was hardly a failure.  19.35 million Famicoms were sold compared to 4.5 million disk systems.  As it found its way into at least 20% of Japanese Famicoms, as an add-on it would appear to be successful.  This is despite buyers having already paid 14,800 Yen for a Famicom.  Nintendo made money off each console sold.  Also, after the release of Famicom Grand Prix II: 3D Hot Rally on April 14, 1988, Nintendo no longer devoted exclusive games to the system, with the exception of PC-style adventure games.

Third parties interest in the system and the number of games released for it dried up by the end of 1988.  Some major developers like Capcom and Namco did not devote much attention to the disk system.  The main advantages of the disk system, namely space and saving, had quickly become affordable in cartridges and companies would charge extra for the privilege. Moreover, Nintendo's own licensing policies swallowed up a large portion of the profits, already smaller due to the lower prices for disk-based games.  Piracy was pretty commonplace, despite Nintendo's security measures.

Nintendo set up Disk Writer kiosks in stores across Japan to allow gamers to purchase new disks and rewrite old disks.  Considering that renting games was illegal in Japan, this was a good way to allow children to sample many games at reasonable prices.  This may have worked relatively well in Japan's more densely populated urban areas, but the more rural areas may have felt left out due to the distance required to travel to get to a shop with a Disk Writer.  Nintendo had to periodically service these machines with new games.

Unfortunately, this device is probably the most unreliable device Nintendo ever made.  The disk had no dust cover on them, making them prone to dust.  Like floppy all disks, the magnetic media can wear out over time and stray electromagnetism can make bits unreliable.  In fact, I have read of people recently buying disks sealed in the box and having them fail.  ROM cartridges are far more robust.

The disk drive itself has a head that will need cleaning, and the custom format means that getting disk cleaning disks will be tricky.  The drive belts will become loose, can break over time or even melt, and the circumference is a custom length.  Although the NES front loader cartridge connector will win no awards here, the pins can be cleaned and bent back.  Nintendo must have had made a pretty penny replacing drive belts for systems out of warranty and they offered the service until 2003.

The disk system came with a RAM adapter.  Inside this RAM adapter was a custom ASIC chip called the 2C33 that interfaced with the disk drive, provided the extra sound channel and came embedded with an 8KB BIOS ROM.  The sound channel modulates an arbitrary 6-bit waveform.  The RAM adapter also contained 32KB of RAM for Program Memory and 8KB of RAM for Character Graphics Memory.  Not unlike the Starpath Supercharger for the Atari 2600, the use of RAM allowed games to split the amount they would use for code and the amount of extra RAM they could use.  To load new data required reading from the disk.  Reading from the disk introduced load times to Famicom players.  For example, it can take 10 seconds to create a new character in Legend of Zelda and 45 seconds to load a game from the menu in Metroid, not accounting for the time it takes to flip the disk.

The disks are 3" wide, narrower than the common 3.5" disks.  They are Mitsumi Quick Disks with some extra plastic on the end that is molded with NINTENDO.  Real Nintendo disks are usually yellow and have no metal dusk cover, but Nintendo did release some special blue disks with metal dust covers.  This acts to prevent non-Nintendo disks from being used because the drive has a mold that must fit some of the holes in that word, but this was quickly circumvented.  The disks themselves can offer up to 65500 usable bytes of storage for a game on each side of the disk.  However, some of that space is taken up by sychronization bits, checksums and headers, so the actual space available to the programmer is less than the nominal amount.  With a cartridge, just about every byte is freely available for the programmer to use.  Also, there are no load times with cartridges and if the game is larger than 64KB, no disk swapping is required.  Standard Famicom cartridges could store only 40KB without additional hardware.  A 128KB cartridge game has more space available to it than a double-sided disk game.

The drive itself could be powered by the included AC adapter (you can use a Sega Genesis adapter here in the US) or 6-C Cell batteries.  Apparently power strips were not yet ubiquitous in Japan and there was no room left in the outlet when the TV and Famicom were connected.  The batteries, beastly as they are, should last for quite a while because the disk drive's motor is not always active.

Interestingly, Nintendo had already released a keyboard for the Famicom that plugged into the Famicom's expansion port.  This keyboard came with and was only used with the Family BASIC cartridges.  Family BASIC saved data to the the Famicom Data Recorder, a cassette recorder that plugged into the audio ports of the keyboard.  The cartridge contained only 32KB/8KB of ROM and 2KB or 4KB of battery backed RAM.  Nintendo could have had their console behave more like a "Family Computer" had they released a BASIC disk, but never did so.  Disk based storage is far more preferable to cassette based storage.

Most FDS-exclusive games came one disk, using two disk sides.  Many of the cartridge ports only required one side of a disk, leaving the other side free for a different game.  The PC-adventure style games were typically released in two parts with part 2 being released typically later than part one and require four disk sides.

One thing the FDS had going for it is Zelda no Densetsu : The Hyrule Fantasy (The Legend of Zelda overseas).  No console, let alone an add-on, could ask for a finer launch title.  Many game designers would be happy if they produced one bona-fide classic, but Shigeru Miyamoto produced his third indisputable masterpiece after Donkey Kong and Super Mario Bros with Zelda.  Zelda offered Famicom players a unique experience.  It had puzzles, tons of secrets, unique enemies, multiple items to equip and for the time what must have seemed like a gigantic world.  Yet though that world was large, it was finite and almost no two screens were exactly alike.  Unlike many other games, then and now, it did not force you to do things in strict sequence.  As icing on the cake, when you completed the game, there was a second, harder quest thrown in for free!

To me and many other non-Japanese NES fans, the most interesting aspect of Famicom Disk System games are the games that were ported to the NES.  Fortunately Nintendo released Zelda as its first battery-backup cartridge overseas.  It knew it had something special on its hands, and sought to impress people with a shiny gold box and cartridge.  Considering Zelda sold several million copies, they were literally on the money.

Zelda cartridge is a good port of Zelda FDS.  You loose the extra sound channel, but it is chiefly used during the intro and ending credits, like most other of Nintendo's FDS games that were ported to cartridge.  Nintendo did not seem to use the extra sound channel for music during gameplay but did use it for sound effects.  Sound effects like Link throwing his sword and the doors opening in Metroid sound much more impressive compared to their NES counterparts.

When Nintendo ported Zelda to cartridge and released in July, 1987, they implemented a battery backed save mechanism.  The battery would keep an S-RAM in the cartridge powered so it would not lose its memory when the system was turned off.  It was the first NES cartridge released with a battery backed save.  The next battery backed cart would be Zelda 2, released in December, 1988.  Battery backed games were expensive, but far less common in the US than in Japan.  Of the roughly 750 US cartridges released during the NES's lifetime, only 56 had batteries.  By contrast, even though there were just over 1,050 Japanese Famicom cartridges, at least 200 had batteries.  Also, every FDS game had the potential to save.

Back in the 1980s, when Japanese games were ported to the US, many had minimal text to translate.  Some Japanese games used English throughout (if the game was fairly light on text) because most Japanese children would be expected to understand some English words and even simple sentences. Other games would use Japanese mostly or entirely thoughout.  The more text, the less likely the port as translation cost time and made things more difficult when porting.  Many of the games that were text heavy and saw ports usually had lots of "Engrish" until development companies began assigning these tasks to people who could actually speak English.  This would be apparent in games with lots of text like both Zelda and Castlevania II.  The Engrish in those games made many dialogues and hints seem truly cryptic.

However, games in the 1980s themselves were pretty cryptic when it came to clues.  Ultima : Exodus, even before it was ported to the NES, was very terse when it came to clues.  Limited disk or cartridge space and the lack of compression tended to cause text to get the clipped shrift.  The FDS version of Zelda also had its obscure hints, as you can read here : http://legendsoflocalization.com/the-legend-of-zelda/first-quest/  Dracula II : Nori no Fuuin, another text heavy FDS game that was ported over to the NES as Castlevania II : Simon's Quest, also has its fair share of head-scratchers : http://bisqwit.iki.fi/cv2fin/diff

Several FDS games, including Link no Boken, Doki Doki Panic and Dracula II, when ported, used 256KB carts.  The porters had more than double the space, and not all of it was taken up by the extra space needed to store English text over Japanese text.  In the US version of Zelda II, each dungeon had its own set of background tiles, some bosses were redesigned and the battle music is more complex.  Castlevania II has much better music than Dracula II, the percussion channel in the NES is used to better effect than the extra FDS sound channel.  Super Mario Bros 2 has much more animation than Doki Doki Panic.  However, Jackal has an extra stage, cut-scenes and can scroll the screen horizontally as well as vertically compared to its FDS counterpart (Akai Yousai) and the cart only has 128KB.

There can be some subtle differences between the original cart release and an FDS port.  Two games that original appeared as a cart, Wrecking Crew and Excitebike used the Famicom Data Recorder (a cassette recorder) to save custom levels and tracks.  When ported over to the FDS (the latter as Vs. Excitebike), they saved to disk.  While Super Mario Bros. for FDS does not support saving to disk, it does have a completely different minus world (consisting of three levels) that can be completed.

Many games, when ported over to cartridge, lost their ability to save games.  This includes Castlevania, Castlevania II, Dr. Chaos, Kid Icarus, Metroid, Mystery Quest and Super Mario Bros. 2., and Section Z.  Castlevania II, Dr. Chaos, Kid Icarus and Metroid use passwords, and the ability to have fun with custom passwords today makes them, in my opinion, more interesting than standard save games.  Of course, Japanese gamers did not have to write down these passwords and hope they did not make any errors or confuse a 0 with an O or a 1 with an l.  (At least we weren't subject to the intimidating 52 character long passwords of Dragon Quest II or the insane 104 character long password of the Japanese version of Maniac Mansion).  The rest allowed for continuing after you died (limited in the case of Super Mario Bros. 2).

Toward the end of the Famicom's life, there were a few ports of games that were released on Disk to Famicom Cartridge.  In each case, Zelda, Akumajou Dracula and Moero Twinbee, the overseas cartridge versions were taken as the base for the reverse port and took what they could and needed from the disk versions.  Cartridge Akumajou Densetsu loses saving, but gains an easy mode.  Moreo Twinbee (released as Stinger in the US) also has the easy mode and retains the three player mode of the disk version, which works by plugging a controller into the Famicom expansion port.

Two FDS games, when ported to NES cartridges were given a complete overhaul.  Roger Rabbit became The Bugs Bunny Crazy Castle.  LJN obtained the rights to publish a Roger Rabbit NES game, so Kemco had to replace Roger Rabbit with Bugs Bunny when they released a cartridge based on the FDS game.  The result was little more than a sprite hack, with Roger being replaced by Bugs and the Weasels being replaced by multi-colored Sylvesters.  Crazy Castle also had Yosemite Sam, Daffy Duck and Wile E. Coyote as enemies, but they appeared far more seldomly.  Roger Rabbit changes them into the Ink and Paint Club Gorilla, the Penguin Waiters from the Ink and Paint Club, and Judge Doom.  The object of Roger Rabbit is to rescue Jessica Rabbit, Bugs Bunny has to rescue Honey Bunny.  (This was 1989, and Lola Bunny, his modern girlfriend, was created for Space Jam in 1996).

In porting Doki Doki Panic to Super Mario Bros 2, Nintendo made major changes.  The replaced the original characters entirely with Mario characters, changed the plot entirely, modified sprites and replaced music.  In Doki Doki Panic, each character had to progress through the levels on their own, and the player could save the game for each world they completed with a character.  For Super Mario Bros 2., Nintendo allowed the player to select from any of the four characters each time they entered a new level or lost a life, but they also eliminated the ability to save your game.  Finally, to see the true ending in Doki Doki Panic, you had to complete the game with all four characters.  The NES version will show you the full ending by beating the game once, but only allows you two continues.  Here is a more visual and detailed depiction of the changes : http://www.themushroomkingdom.net/smb2_ddp.shtml

If you look inside a Metroid or Kid Icarus cartridge, you will see an extra RAM chip.  In fact, these games use the same cartridge board as Zelda, and even have a place on them for a battery.  Apparently, these games needed the flexibility of more RAM than the NES could provide.  The FDS could provide more RAM (at the expense of ROM), but they needed extra RAM for the cartridge versions.  It seems that Nintendo didn't want to spend the extra nickel to put in a battery or the programmer's work on the password system was too far to revert before they discovered that the games needed extra RAM.  Similarly, Super Mario Bros. 2 also has an extra RAM chip, but its board does not have space for a battery.

Super Mario Bros. 2 for the FDS was not released for the NES, but was released for the SNES as "The Lost Levels" and a portion of it (Worlds 1-8 only) for the Gameboy Color as Super Mario Bros. Deluxe.  It is well known that Super Mario Bros 2. FDS was rejected for being too difficult for the US market. However, there are differences between the original FDS version and the SNES remake.  The SNES cart remembers the level saved, unlike the FDS version which only remembers the world.  World 9 requires the player to complete every level of Worlds 1-8 without warping, but the FDS only gives you one life and loops back to 9-1 after you beat 9-4.  This is closer to the original minus world concept of Super Mario Bros.  In the SNES version, you go to World A-1 when you beat 9-4.  Also, the player must beat the game eight times in the FDS version and press A on the title screen to progress to World A-1, whereas you only need to complete Would 8-4 (with or without warping) to get to World A-1.  Thus the FDS game does save how many times you beat the game.

One annoyance with FDS games is that, unless you obtain a pristine, new-in-box copy of a game, you are likely going to be saddled with somebody's old saves.  Most NES games allow you to delete old saves and those deletions will stick  If the NES game does not, the game will be restored to its pristine condition when the battery fails or is removed.  While the two Zelda games allow you to restore the game to a pristine state with no save games, the rest of the games mentioned here do not.  Zelda and its sequel will write to disk if you kill a game or start a new game, but the others will only write to disk if you start a new game.  Therefore you will always have at least one character on your disk.