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What is a DOS game?

It seemed like an innocent enough question to me. Two game developers were talking, one older than the other, and the older said something about developing a DOS game, and then the younger asked, what’s a DOS game?

A DOS game is a game that runs on PC hardware but under MS-DOS or PC DOS rather than Microsoft Windows.

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Advantages and disadvantages of MS-DOS

MS-DOS was the dominant computer operating system of the 1980s and early 1990s. It was the operating system most people loved to hate, yet it remained a bestseller. It formed the foundation of Microsoft’s market dominance of the 1990s and beyond. What were the advantages and disadvantages of MS-DOS?

MS-DOS stood for Microsoft Disk Operating System. It also licensed it to IBM, who branded it PC DOS, for Personal Computer Disk Operating System. The differences between the two were relatively minor and they are more or less interchangeable, especially at versions 5.0 and lower.

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Building DOS gaming PCs

The ultimate DOS gaming PC is a topic that I’ve seen come up in forums frequently, and that I’ve been asked directly a number of times. I guess since I published advice on running DOS games on Windows PCs on two continents, people figured I knew something about that. I guess I fooled them!

The trouble is that no single PC can really be the “ultimate” DOS game machine. Well, not if your goal is to be able to optimally run everything from early 1980s titles designed for the original IBM PC up to the last DOS version of Quake. I learned that the hard way in 1995 or 1996, even before Quake existed.Read More »Building DOS gaming PCs

DOS nostalgia?

I’ve been getting nostalgic for DOS lately. Well, certain DOS games *cough* Railroad Tycoon *cough*.

One of my coworkers’ wives is nostalgic for ’80s boy bands whose name I refuse to mention, so there certainly are worse things for me to be nostalgic about. Sure, DOS is terrible, but not that terrible.I’m using an old 128MB compact flash card in a cheap CF-IDE adapter. While 128 megs isn’t a lot, it’s adequate if you’re not going to have Windows and Windows apps loaded. After all, you can get all the DOS you’ll ever need for game playing in less than 1.5 megs. Even still, I’ll probably pick up a bigger card the next time I order stuff from Newegg. A 4 gig card is cheap, and to DOS, 4 gigs is huge.

DOS boots to a C prompt in about five seconds off the CF card, and a good chunk of that is the CD-ROM driver scanning the IDE channels for drives. The system takes a lot longer to POST than it does to boot.

The system itself is an old Micron Pentium II-266. Severe overkill, but I hear Railroad Tycoon Deluxe really wants a fast CPU. Plus, my 486 is missing in action right now anyway.

Now that I have the system running, I need to hunt down drivers for the system’s Sound Blaster card. Then I’ll get Railroad Tycoon Deluxe loaded, and then all I’ll have to do is find a little time to play it. That last step will probably be the hardest part.

If the games I want to play don’t like the P2 (unlikely but possible), I’ll just dig out a Pentium 75 or a 486 from somewhere. That won’t be a huge setback, since I’ll have everything I need gathered up to build the system at that point.

Need to squeeze a little more on that floppy?

I’ve been experimenting again with bootdisks and the FreeDOS project came to mind.

Boot floppies are getting rarer but they’re still hard to avoid completely. I think FreeDOS is worth a look for a variety of reasons.Its system files take up half the space of Win9x’s DOS. That extra 100K on the disk can make the difference between your tools fitting on a floppy or not.

FreeDOS supports FAT32. There’s an unofficial DR-DOS fork that does as well, but the licensing terms of FreeDOS are a whole lot more clear.

The FreeDOS FORMAT.EXE can overformat disks. If you use more than 80 tracks, the disks have problems in some machines, but a 1.68 megabyte disk using extra sectors per track should be OK. Concerned about overformatting disks? The Amiga’s default high-density disk format was 1.76 megabytes. That extra 240K can make a big difference, especially when coupled with that 100K you’ve already saved. The syntax to make a bootable 1.68 meg disk: FORMAT A: /F:1680 /S

The syntax for a 1.74 meg disk: FORMAT A: /F:1743 /S

The FreeDOS command interpreter includes command history, so you don’t need to make space on the disk or in low memory for DOSKEY.

Using FreeDOS and its 1.68 meg floppy, I was able to squeeze Ghost 8.1 (a 1.3 meg monster) onto a boot floppy and still have 197,632 bytes free to play with. With that kind of space left, if need be, one could format the disk with FreeDOS, then SYS it under Win9x and run MS-DOS 7 on it.

If you still need to squeeze a little more space, get the freeware FDFormat, which can also format oversized floppies and lets you reduce the root directory down to 16 entries from the default 224, which gives you a few more kilobytes of usable space. If you need to put more than 16 files on the disk, create a subdirectory and put your files in the subdirectory. The syntax would be FDFORMAT /D16 /F168 /S. Substitute /F172 for a bigger disk. To increase the performance of the floppy (who doesn’t want the slowpoke floppy to be a bit faster?) add the /X:2 /Y:3 options. A boot disk formatted this way yields 1,595,904 free bytes with the FreeDOS boot files installed.

That’s enough space to be almost useful for something again. You’ll at least be able to fit more on Bart’s modular disks or Brad’s network boot disk.

Running ancient DOS games on modern Windows

So today I was one of at least two people trying to help Jerry Pournelle get the original Railroad Tycoon running under Windows XP. The secret is DOSBox, a cross-platform DOS emulator.DOSBox emulates a 386-class PC, with VGA and a SoundBlaster, under multiple operating systems–most notably, Linux and Win32. It’s pretty slick in a number of ways. Boot it up, and you’ve instantly got sound configured and 637K of conventional memory available, along with enough extended memory to round out 16 megs. All without messing around with arcane and archaic memory manager commands in config.sys. (Remember that?)

When Jerry last e-mailed me, the game was running but he was having difficulty getting the mouse to work, even when hitting ctrl-f10 to lock the mouse. I suspect it’s easier to get PS/2 mice to work with the emulator than USB mice, as under Windows USB is a different driver. But I’m not certain. I’m still trying to find my box of old DOS games so I can even test the emulator properly. Based on his site, it looks like he got it working, but didn’t elaborate on what it took. I don’t blame him–if I’d just gotten the original Railroad Tycoon running again, I think I’d have better things to do than write back a dozen people to say, “It works.”

Because DOSBox actually emulates everything and doesn’t rely on the hardware, you need a GHz-plus machine to get 486 speed out of it. That’s the price you pay for higher compatibility. The cardinal rule of emulation has always been that any machine can perfectly emulate any other machine as long as speed is not a factor. Fortunately, those aren’t especially rare or expensive these days.

I’m definitely going to keep looking for that box of old floppies. My 1.3 GHz Athlon ought to run that old DOS stuff pretty well, I would think. I’ve been wishing for about six or seven years that something like this would come along. Long enough that I wasn’t even ready for it when it appeared in a reasonably mature state…