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View Full Version : How would one copy cartridge media to disk ?



Micom 2000
January 15th, 2010, 01:21 PM
I have a lot of old cartridges from various platforms. I also have all the appliances they ran on. Is there any way of copying these cartridges to disk media ? Altho the cartridges are digital based, and don't suffer the frailities of tape or FDDs, none of them lasts forever.

Lawrence

carlsson
January 15th, 2010, 01:53 PM
It depends a lot about the cartridge and system, if they are autostarting or you had to start them by hand. Some of them may contain ROM or EPROM in a nice socket. In that case if you can open the case without damaging it, you could lift the chip and put into an EPROM programmer to "dump" it as it is called.

However most of the time that is not possible. The other option would then be to trick the computer to not autostart the cartridge. Usually there is a signature or checksum in ROM that the computer checks for. If it is valid, the game will start. There are at least two ways to circumvent this. The first would be to perform modifications onto your computer. It could involve replacing a system ROM with a custom one that mostly ignores cartridges upon startup. Perhaps sometimes it can be a matter of cutting a wire or so, but it would permanently damage the computer.

The second option is to use a cartridge expander for those systems which use those. I'm mainly familiar with the Commodore models. Both the VIC-20 and C64 had the option to add an expander with 2-5 slots. Either you have push buttons to activate each slot or they will all be active according to an order of priority. Theoretically pushing a button while the computer is running should not cause any harm, but you may want to get a second opinion if you're of the careful kind. However what happens when the button is pushed is that the computer can get to read the cartridge but still will remain at the Basic prompt or similar. From this stage, we can write or run a small program that simply reads the cartridge ROM from memory and stores on disk.

One gotcha to watch out for is copy protection. Some systems have a memory map where cartridges fill out a hole, which means you would need to add a memory expansion to fill out the same hole. Other systems have built-in RAM to cover all otherwise unclaimed memory. In both cases, you may find the dumped cartridge image refuses to run. Often it is because the program is trying to overwrite itself! Remember as long as you run a ROM cartridge, writes will not have any effect. When you move over to RAM however, the program can very easily overwrite itself. At this point you would need to disassemble and make changes to the cartridge dump to remove the protection. I won't dwelve further into details as this is a grey zone.

Sometimes there exists special devices used to take backups of cartridges. Those would mainly consist of a cartridge port connector and some circuitry to read the cartridge, but not enough hardware to actually run it.

As you see, there is not one definitive answer. Most of your cartridges probably have been backed up by other people and you will be able to find them somewhere on the Internet. Some are harder to find than others.

Micom 2000
January 15th, 2010, 04:46 PM
I do have a 4-cartridge commodore rig with the 80 column option. Perhaps it would also work with the Vic-20 cartridges if you could capture the ROM before it executes. I also have an Adam with the Coleco attachment. If you could transfer to cassette, you could then transfer to FDD. The 8-bit Atari's are another problem but do have an fdd. The CoCo would present another problem even tho I have the FDD cartridge and there were 2 cartridge expanders. Atari 2600 and TI machines would be also an insurmountable problem unless you had a ROM-dump machine. I've never run across these cartridge back-up devices. Were they very common ? And where they machine specific ? One would consider them an Eprom reader without the editing capabilities. I find it strange there weren't more more of these in the cartridge game explosion of the early 80s.

In the present era where gaming is such a major market, and emulators are endemic, one would think that such a product would be a natural.
The issueing of so many ancient cartridge games on disk-media shows it is possible and I can't imagine that all of them went thru the process of difficult ROM-Dumps or computer modifications to obtain their product. Most dedicated gamers of course want the experience on the original machines, but there seems to be a big market for emulation and old cartridge programs out there. Were they all products of ROM-dumps ?

In my own case it's more as a conservation concern of these many familiar programs before they expire from normal physical degredation.

Lawrence

carlsson
January 16th, 2010, 05:31 AM
Yes, a device that takes a full cartridge would need to specific to each system, since cartridges not even physically (*) are compatible with eachother. That is why you usually can identify which system a cartridge fits just by looking at it and count the number of pins on the edge connector. Actually there recently was another thread about a new device which takes Sega Genesis and Super Nintendo game cartridges, with the intent to use the physical game cartridge when playing on your emulator, or of couse take backups.

As I wrote, most of the classic cartridges have been dumped at least 10-15 years ago and float around at various FTP areas. If there emerges an unknown cartridge, several people in respective communities usually have the means to dump them, possibly involving special hardware. I can't say how many cartridges or systems were permanently modified for this purpose, but I am quite confident each system requires its own variant on the dumping process. To some part the same can be said for tapes and disks too, although you usually can read the raw data from a foreign disk even if you have no means to parse it.

(*) The closest match I know is mixing Intellivision and Commodore 64 cartridges. If you use a lot of force, you may be able to jam an Intellivision cartridge into the C64, but I won't be held responsible for what happens when you power on the computer.

Ksarul
January 17th, 2010, 05:41 AM
For at least one of the machines you listed as potentially problematic, the TI, there isn't a real problem reading the cartridge out. Navarone made a three-cartridge expander that you could switch between the cartridges. here were several assembly utilities that would then dump the cartridge contents to disk. A purely ROM cartridge of 8 or 16 K could usually be tricked or modified to run in the normal TI 32K RAM expansion space. There were also assembly routines that would trick some of the GROM based cartridges to do the same (GROMs were 6K memory chips with an internal 13-bit auto-incrementing address bus, specific to TI). Many larger cartridges could only be run using one of the many GRAM simulators (a RAM version of the GROM). Those included the Wiesbaden Supermodul I and II, the Miller's Graphics GRAM Kracker, the Mechatronics GRAM Karte, the Horizon P-GRAM, the SNUG HSGPL, and several TI prototype devices (Texas Instruments built these prototypes for internal use, so they are both rare and individually unique to operate--I have three of the five types they made, and they are all different). The other GRAM devices show up on eBay now and then. I think there may be a GRAM Kracker up now, if it hasn't closed yet.

Micom 2000
January 18th, 2010, 09:50 AM
For the most part it seems this is above my capacity or more problematic than it's worth. Oh well. Thanks all.

Lawrence

hargle
January 18th, 2010, 10:49 AM
I suspect that there isn't a cartridge that isn't already dumped by someone else already. "full sets" of zip files of every single cart known to humankind for each platform exists online already, you just need to know where to look.
(at least for gaming systems and home computers)

The nice thing about said collections is that a lot of the roms are verified as known good dumps, so that takes the risk out of doing it yourself; not exactly knowing if what you pulled from the cart is exactly complete and accurate.

Micom 2000
January 18th, 2010, 06:21 PM
Well I have a medium-suzed collection of Colleco carts, and found the Wiki page with all known listings. I haven't compared it yet with the carts I have, but they're likely all on the extensive list. I also have a number of Adam tapes, but that is another problem. It shouldn't be a great problem to transfer them to another tape, altho rubber melt-down, as I learned unfortunately from some of my 8-track tapes could be a problem.

My 2600 carts are also all , as you suggest, likely already transferred from that popular medium. The Vic-20 and my few C-64 carts could also possibly be transferred using my multi-cart accessory to a 1541 fdd as Carlsson suggests. Similarly my Atari 8 bit ones, altho I don't have a multidisk adaptor but do have 2 or more slots. Most of those carts are system related and surely the emulator people have figured out how to transfer such as Atari Basic to disk. On the CoCo, and in regard to the all-important fdd cart, Cloud Nine has done some incredible hacks, even to adding a hdd. I only have about 2 TI disks, so , with all apologies to Ksarul, it's not a problem for me. That leaves only the PCjr, for which I have only 2 Lotus 123, and a couple of game carts, which Mike Brutman has well in hand.

Lawrence

hargle
January 19th, 2010, 06:12 AM
Yeah, I've found that most of the dumped sets of roms out there are so extensive, that if you have ever even heard of the title, it's already been dumped.

WRT your PCjr, you may be interested in some of the stuff I've been doing with this:
http://www.waste.org/~winkles/JR_CARTS.ZIP

This is a total WIP, long ago set aside for other projects, but I hope to get back to it someday. Just write the img file to a 360k floppy and boot it in your jr.