Old DOS disk works on Windows, but it’s risky

Question: Can an older DOS boot disk be used on a computer that runs Windows 95 as the operating system? There was no clear consensus among my fellow workers on this matter.

Answer: Sure, you can boot the machine with an older version of MS-DOS. The question is: do you want to?

I liken it to playing hockey with a clay pigeon in a stadium of shotgun-toting spectators. It’s dangerous.

A DOS boot disk will boot a Windows 95 machine, but when it reads and displays a long filename it will be shortened to the old 8.3 file format. That’s eight characters, a period, then a three-character file format extension, like “auntedna.doc” or “hairylip.gif”.

Under Windows 95, file names can contain up to 255 characters, including spaces (except for the following punctuation characters: / : * ? ” > < |). So an older version of DOS would read a long Windows 95 file name like “Aunt Edna smooching Andy at Christmas.jpg” and shorten it to “aunted~1.doc”. More than one file name starting with the words “Aunt Edna” (God forbid) would be indistinguishable from each other because they would be shortened to the 8.3 format.

The problem gets even nastier if your version of Windows 95 uses a FAT32 volume. What the heck is that, you might ask in trepidation, fearing more obscure references to my hairy-lipped aunt? “FAT” is short for File Allocation Table. That’s a kind of index the operating system uses to locate files on a disk. A FAT32 volume is a 32-bit FAT that allows storage of path names greater that 256 characters in length and supports hard drives larger than 2 Gigabytes.

Your system uses FAT32 if your version of Windows 95 is 4.00.950b or 4.00.950c. It’s an upgrade that only comes with new PCs and will be fully integrated into Windows 98 when it’s released. To check your version, right click on your My Computer icon and select Properties.

Another word of warning comes from Michael Hanley, a senior help desk technician at Microsoft Canada. “If you have a drive formatted with FAT 32, you will be able to boot up from the old DOS floppy, but not be able to see the drive. To read that drive with a bootable floppy, you’ll need to make an emergency recovery disk with a system that has one of the newer versions of Windows 95 installed. The disk can be made by going to Control Panel, Add/Remove Programs, Startup disk, and then click ‘create disk,’ ” said Hanley.

To read more information about emergency boot disks, click Start > Help, type boot disk and click the Display button on your Windows 95 system.

TechnologyTips Notes:

SUCCESSFUL UPGRADE: A couple of weeks ago, M.W. asked about upgrading his Pentium 133 mHz chip to an MMX-enabled CPU, and I recommended buying a Pentium Overdrive Chip from Intel. He reports all is well.

“My brother and his wife bought me the 200 mHz MMX Overdrive processor for Christmas and they let me test it right away. Out went my Pentium 133,” he said, “and in went the Overdrive.

“Intel’s home page said it should work and it did! I didn’t have to change jumpers or anything. The fan on the new chip was smart enough to draw its power right from the chip’s socket, and the casing for the chip itself dealt with the voltage problems.

“The Overdrive chip comes in a box, and includes a nifty piece of software on a floppy disk that probes your PC to tell you if it will really run the new Overdrive processor OK. After installing the new processor, I ran the software again, and it ran diagnostics to make sure the new chip worked as it was supposed to.”

The real test, he said, was playing the game MechWarrior II, and its predecessor, Heavy Gear. “It caused no freezes or hang-ups, but the performance was just kick-ass!”

This upgrade was a success story. “For $500 or so, I basically have a system that can hide its age for another year or so before it seems completely passe.”

A Hamilton Spectator reader recently asked me to recommend a book that explains how to repair and upgrade computers in non-complicated language. The best book I’ve come across so far is Linda Rohrbough’s Upgrade Your Own PC, published by IDG Books. The copy I have is a year old now, but definitely is still mostly relevant, which is hard to say about most computer books, given the pace of change in the computer industry.