Convert Multi-Disk Games to Single Disk?

[pcrow]

Has anyone ever tried to convert multi-disk games to single-disk images?  I'm thinking of games like Ultima IV or Alternate Reality in particular, but really there are tons of such games that would be more convenient as a single image.  For the two mentioned, the simplest idea would be to create a image with 2880 128-byte sectors (4*720 sectors), and have the logic of the game add 720 times the disk number (0-3) and drop the prompts to switch disks.  A more ideal solution would be to switch to 256-byte sectors so that it's a standard DSDD 360K image which would work with regular hardware (no SIO2PC or such required).  Of course, the crazy idea would be to convert them to run on a cartridge with a player save disk, but that would probably take a huge amount of work.  (I can imagine using the cartridge hardware register window at D5xx as a bank selected ROM disk, so converting to a cartridge might not be that much worse than making a single disk image.)

 

Really, the worst part about many multi-disk games is the lack of support for multiple drives.

[TGB1718]

I think the main problem here would be games that load data directly from sectors i.e. there is no directory/files

on the disk, you would have to know what sectors to load off the extra disks, and renumber as required, no mean feat.

and of course if you use bigger sectors, a complete renumber.

[Wrathchild]

Alternate Reality : The City is a special case as it uses its own SIO routines to handle the Disk I/O and there are multiple instances of it as extra copy protection.

[Rybags]

I did a little project some time back that I called ATRLoad - it allowed loading large programs entirely into Ram from a single file.

I did Spelunker, though a single disk image to begin with, allows it to exist in a file and fit into Ram beyond 48K then quickly stream the level data instead of loading it as the game plays.

Such a thing in theory could be done with some multi-disk games - I had the idea to use hotkeys to tell the handler to switch among loaded images.

 

Ultimately though, doing that or multiple sides into one image or file can be a case by case project that can be fairly intensive.

But looking at it from a convenience point of view, there's probably not a huge number of games that would benefit - the AR games for sure but ones where you just load then flip and forget, the effort might not be worth the end result.

[Wrathchild]

I've done quite a few and yes, they are pretty much a case of analysing how each one it working and react accordingly. Modern emulators and debug tools can aid immensely here as disk access can be traced etc and the load/save routines identified easily and work arounds developed.

 

I've looked at some DOS based multi-disk titles of late and tried to see if they could be moved to, say, a single image using LiteDOS and to the most part that maybe possible but some titles annoyingly have the same named file on different sides but with different content, so this can be a pain to then rename and update the references to it.

[Wrathchild]

10 hours ago, pcrow said:

Of course, the crazy idea would be to convert them to run on a cartridge with a player save disk, but that would probably take a huge amount of work.

There are @Shawn Jefferson's Ultima ports on the AtariMax site: Ultima II, Ultima III, Ultima IV

[ggn]

From personal experience (not on this platform, but https://d-bug.me/patch.php) there are many ways such a project could go, a few of them are mentioned already:

1. Extract the data from disk, place it into files (or as raw data really) into a large enough disk, then patch the game loader (or loaders) to load the requested data from the new locations
2. Expanding on the above, pack the data so they'll consume less space so there's better chance of the game fitting into a conventional disk
3. For systems with expanded memory, load all data in one go and then patch the game loader(s) to jump to a "sector emulator" that will feed the data into the game
4. Why stop at floppies or carts? Store the data on a hard drive partition and then suddenly space stops being a hurdle
5. For game saves, either use the original game routines (so, use a save disk) or patch them according to whatever fits the chosen scenario from the above list

And before people start complaining about hard disk being too hard as the game might overwrite DOS/drivers, we have also solved this problem! https://d-bug.me/uls.php is a loading/saving system that swaps out the OS to other parts of RAM, enables you to run the game, and when it's time to do any disk access it swaps the system back in, performs the load, swaps the system out again, and feeds the data back to the game :).

 

Anyway, all this is easier said than done, but depending on the amount of work someone is willing to put into such a project, all should be doable. And of course none of the above suggestions assumes a magical system that will do all this transparently - there will be manual work required.

Edited December 31, 2023 by ggn

[ggn]

Also, I just remembered 

 

[Mr.Bacardi]

Here's an ATR of the german adventure game "Null Grad Nord" that I just did because I wanted to do a walkthrough Youtube video for this game...

Luckily the files from Homesoft's version can be copied to another disk, so it was not difficult to move everything to a single atr file using BiboDOS.

No other modifications were done, so you still get prompted to turn disk, but you can simply ignore the message now!

Null Grad Nord (Axis) 360k (BiboDOS).atr

Edited December 31, 2023 by Mr.Bacardi
typo

[+SoulBuster]

Nice idea.  Keep in mind games like Brimstone that require two disk drives.

[Peri Noid]

19 hours ago, pcrow said:

Has anyone ever tried to convert multi-disk games to single-disk images?

A Hyper-XF powered XF551 drive, especially a 3.5" version, can be handy here since it is able to support up to 4 DD drives (partitions) on a single 720KB disk (two DD images on a double sided 360KB floppy). But such disks cannot be simply used on SIO2SD/SDrive/FujiNet/etc.

[pcrow]

4 minutes ago, Peri Noid said:

A Hyper-XF powered XF551 drive, especially a 3.5" version, can be handy here since it is able to support up to 4 DD drives (partitions) on a single 720KB disk (two DD images on a double sided 360KB floppy). But such disks cannot be simply used on SIO2SD/SDrive/FujiNet/etc.

For games that support multiple drives to handle their multiple disks, that works nicely, but too many don't.

[magnusfalkirk]

I have a 1mb prototype cartridge image, not sure where I downloaded it from, that someone did of Alternate Reality the City. Haven't played it a lot because there is no way to save the progress.

[magnusfalkirk]

14 hours ago, ggn said:

Also, I just remembered 

 

I bought the catridge Wilhelm did for Alternate Reality the Dungeon. Loving playing it.