C64 Emulation: Floppy Disk Images and How to Use Them
It's easy for someone who grew up with the hardware to forget that some aspects of C64 emulation can be a bit perplexing to a newbie.
The C64 had three main types of media for loading programs. They were 5¼-inch floppy disks, cassette tapes, and cartridges. Other media existed, including 3½-inch floppies in later years, but commercial software in that format was not easy to find.
Here I'll focus on the common floppy disk format, and how to use the disk images found around the web today for use with emulators.
ATTACH AND RUN
Most people want to download their "C64 ROMs" (or r0Mz for the l33tspeak types), load them, and forget about it.* They want their C64 emulator to behave as if you were plugging a cartridge into a Nintendo system, despite the fact that the Commodore 64 was a home computer that used to require a typed in command to kick off the program from a floppy disk.
In most cases, thanks to "Attach and Run" type of options in modern emulators, they can.
Some games or disk images require a little manipulation of the floppy disks during the game. For instance, your disk image, as mentioned here at the C64 Walkabout before, might have multiple programs on it.
LOADING
On a real C64, after turning on or resetting your system, when you knew that your disk has only one program on it, you would type in:
LOAD "*",8,1
The ,8 was to access the floppy disk (a .T64 tape image does not require the 8), and the ,1 was to execute immediately. The asterisk loaded the first available program on the disk. Well, technically it was a little deeper than that, but the result was the same.
Most emulators do this by default when you choose to "Attach and Run" an image. The command is auto-entered.
But what if your disk image has multiple programs?
Well, you'd type:
LOAD "GAME",8,1
With "game" being the name of the game, such as "GRIDRUNNER".
Emulators like VICE will show the directory of the disk in the lower left if you choose to Open a disk image using File, Autostart Disk/Tape Image in the menu.
Simply double-click the name of the game in the disk image contents window, and you won't need to type anything.
On a more primitive C64 emulator you might have to manually type this in yourself. You might even need to type:
LOAD "$",8
then
LIST
This will show you what is on the disk, so you know the name of the file you want to load with a multi-program disk image. It's the equivalent of dir in MS-DOS or ls in Linux.
MULTIPLE DISK GAMES
Many of the more advanced games for the C64 required multiple floppies to store all of the game information. If you download a zipped up set of files and see 3 .D64 files named DUNGEON1, DUNGEON2, DUNGEON3, for example, then the program was originally sold / distributed with multiple floppy disks.
Since the C64 Emulators need to emulate real floppy drive behavior, there is no way that I know of to get around this and the issue of disk swapping that it introduces.
Disk swapping means that in game you'll be asked to swap disks. The game will prompt you with "Insert Disk A" for example.
If you are unsure which disk is required just by the .D64 filenames, attach it, and view the Disk Image contents. The name of the disk should be in the header of the disk image contents.
For example, in Ultima 5, you may be asked to insert the "DUNGEON" disk or the "CASTLE" disk. The .D64 filenames might just be U5A, U5B, etc. All you need to do is "Attach Disk Image", then view the contents of the disk as in the screenshot below.
For most C64 retro gamers, this is about all you need to know. There are some other interesting differences with the "ROMs" used with console game systems, such as the ability to save character/game data onto the actual .D64 disk image.
This means that if you save you characters and their progress in a game and pass that same file to your friend or otherwise distribute it, then your save game data will follow. You may wish instead to use the "Save State" or "Snapshot" feature found in emulators instead, but saving to the disk image is another layer of backing up your games in case you lose track of your snapshot file or want to play the game on a different emulator later (snapshot files may not be compatible between emulators).
In the end, you may not need to know half of the information I've detailed here to enjoy C64 emulation, but in the case you do, I hope this article will help.
Happy Retro Gaming!
* Technically it is incorrect to call a .D64 floppy image file a "ROM". A ROM is, as the acronym implies "Read Only". A floppy disk image that you can write to, therefore is not a "ROM". A C64 Cartridge, on the other hand, might more accurately be called a "ROM".
The C64 had three main types of media for loading programs. They were 5¼-inch floppy disks, cassette tapes, and cartridges. Other media existed, including 3½-inch floppies in later years, but commercial software in that format was not easy to find.
Here I'll focus on the common floppy disk format, and how to use the disk images found around the web today for use with emulators.
ATTACH AND RUN
Most people want to download their "C64 ROMs" (or r0Mz for the l33tspeak types), load them, and forget about it.* They want their C64 emulator to behave as if you were plugging a cartridge into a Nintendo system, despite the fact that the Commodore 64 was a home computer that used to require a typed in command to kick off the program from a floppy disk.
In most cases, thanks to "Attach and Run" type of options in modern emulators, they can.
Some games or disk images require a little manipulation of the floppy disks during the game. For instance, your disk image, as mentioned here at the C64 Walkabout before, might have multiple programs on it.
LOADING
On a real C64, after turning on or resetting your system, when you knew that your disk has only one program on it, you would type in:
LOAD "*",8,1
The ,8 was to access the floppy disk (a .T64 tape image does not require the 8), and the ,1 was to execute immediately. The asterisk loaded the first available program on the disk. Well, technically it was a little deeper than that, but the result was the same.
Most emulators do this by default when you choose to "Attach and Run" an image. The command is auto-entered.
But what if your disk image has multiple programs?
Well, you'd type:
LOAD "GAME",8,1
With "game" being the name of the game, such as "GRIDRUNNER".
Emulators like VICE will show the directory of the disk in the lower left if you choose to Open a disk image using File, Autostart Disk/Tape Image in the menu.
Simply double-click the name of the game in the disk image contents window, and you won't need to type anything.
On a more primitive C64 emulator you might have to manually type this in yourself. You might even need to type:
LOAD "$",8
then
LIST
This will show you what is on the disk, so you know the name of the file you want to load with a multi-program disk image. It's the equivalent of dir in MS-DOS or ls in Linux.
MULTIPLE DISK GAMES
Many of the more advanced games for the C64 required multiple floppies to store all of the game information. If you download a zipped up set of files and see 3 .D64 files named DUNGEON1, DUNGEON2, DUNGEON3, for example, then the program was originally sold / distributed with multiple floppy disks.
Since the C64 Emulators need to emulate real floppy drive behavior, there is no way that I know of to get around this and the issue of disk swapping that it introduces.
Disk swapping means that in game you'll be asked to swap disks. The game will prompt you with "Insert Disk A" for example.
If you are unsure which disk is required just by the .D64 filenames, attach it, and view the Disk Image contents. The name of the disk should be in the header of the disk image contents.
For example, in Ultima 5, you may be asked to insert the "DUNGEON" disk or the "CASTLE" disk. The .D64 filenames might just be U5A, U5B, etc. All you need to do is "Attach Disk Image", then view the contents of the disk as in the screenshot below.
For most C64 retro gamers, this is about all you need to know. There are some other interesting differences with the "ROMs" used with console game systems, such as the ability to save character/game data onto the actual .D64 disk image.
This means that if you save you characters and their progress in a game and pass that same file to your friend or otherwise distribute it, then your save game data will follow. You may wish instead to use the "Save State" or "Snapshot" feature found in emulators instead, but saving to the disk image is another layer of backing up your games in case you lose track of your snapshot file or want to play the game on a different emulator later (snapshot files may not be compatible between emulators).
In the end, you may not need to know half of the information I've detailed here to enjoy C64 emulation, but in the case you do, I hope this article will help.
Happy Retro Gaming!
* Technically it is incorrect to call a .D64 floppy image file a "ROM". A ROM is, as the acronym implies "Read Only". A floppy disk image that you can write to, therefore is not a "ROM". A C64 Cartridge, on the other hand, might more accurately be called a "ROM".
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