Optimizing BIOSes and optimizing DOS

Last Updated on November 19, 2010 by Dave Farquhar

Optimizing the BIOS. Dustin Cook sent in a link to Adrian’s Rojak Pot, at www.adriansrojakpot.com , which includes a BIOS tweaking guide. It’s an absolute must-read. I have a few minor quibbles with a couple of the things he says, particularly about shadowing and caching your ROMs with Windows 9x. He says you shouldn’t do it. He’s right. He says you shouldn’t do it because Microsoft says not to do it with Windows NT, and Windows 9x “shares the same Win32 architecture.” It does and it doesn’t, but that’s flawed logic. Shadowing ROMs isn’t always a bad thing; on some systems that eats up some usable memory and on others it doesn’t, depending on the chipset and BIOS it uses. But it’s pointless because Windows doesn’t use the BIOS for anything, unless you’re in safe mode. Caching ROMs makes very little sense; there’s only so much caching bandwidth to go around so you should spend it on caching memory that’s actually being used for something productive. So who cares about architecture, you shouldn’t cache and shadow your ROMs because Windows will ignore it one way or the other, so those facilities are better spent elsewhere. The same thing is true of Linux.

Still, in spite of this minor flaw I found in a couple of different spots, this is an invaluable guide. Perfect BIOS settings won’t make a Pentium-90 run like a Pentium III, but poor BIOS settings certainly can make a Pentium III run more like a 386DX-40. Chances are your BIOS settings aren’t that bad, but they can probably use some improvement. So if you want the best possible performance from your modern PC, visit Adrian’s. If you want to optimize your 386 or 486 or low-end Pentium, visit the site I mentioned yesterday.

Actually, it wouldn’t be a half-bad idea to take the downloadable versions of both guides, print them, and stick them in a binder for future reference. You’ll never know when you might want to take them with you.

Optimizing DOS again. An awful lot of system speed is psychological. I’d say maybe 75% of it is pure psychology. It doesn’t matter so much whether the system really is fast, just as long as it feels fast. I mentioned yesterday keyboard and screen accelerators. Keyboard accelerators are great for people like me who spend a lot of time in long text files, because you can scroll through them so much faster. A keyboard accelerator makes a big difference in how an old DOS system feels, and it can improve the responsiveness of some DOS games. (Now I got your attention I’m sure.)

Screen accelerators are a bit more of a stretch. Screen accelerators intercept the BIOS calls that write to the screen and replace them with faster, more efficient code. I’d estimate the speedup is anywhere from 10 to 50 percent, depending on how inefficient the PC’s BIOS is and whether it’s shadowing the BIOS into RAM. They don’t speed up graphics at all, just text mode, and then, only those programs that are using the BIOS–some programs already have their own high-speed text routines they use instead. Software compatibility is potentially an issue, but PC power users have been using these things since at least 1985, if not longer, so most of the compatibility issues have long since been fixed.

They only take a couple of kilobytes of memory, and they provide enough of a boost for programs that use the BIOS that they’re more than worth it. With keyboard and screen accelerators loaded in autoexec.bat, that old DEC 386SX/20 feels an awful lot faster. If I had a copy of a DOS version of Microsoft Word, I could use it for writing and it wouldn’t cramp my style much.

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