Category Archives: Floppies

There’s Another Possibility

Four years ago we pondered why on Earth a DOS floppy boot sector might start with 69h, supposedly a “direct jump” opcode. Which is the IMUL instruction on 80186 and later, and not documented on 8086. In the meantime, it … Continue reading

Posted in DOS, Floppies | 46 Comments

More Wobbles

This is a follow-up to a previous post. I’ve had a chance to spend more time recovering the two dead PS/2 Model 80s. The first step was replacing the CMOS batteries because without a functioning backup battery, a PS/2 is … Continue reading

Posted in Floppies, IBM, PS/2 | 10 Comments

Wobbly Floppy Drive?

Over the weekend I tried to revive a PS/2 Model 80 whose CMOS battery died (after 25 years!). Finding a replacement battery fortunately isn’t difficult (6V lithium “photo” battery), but recreating the configuration informationĀ of course requires a reference floppy and … Continue reading

Posted in Floppies, IBM, Plug and Play, PS/2 | 28 Comments

Floppy Capacity Math

After more or less accidentally coming across a BBS listing of various high-capacity floppy formatting programs, I began wondering: How much data can really be stored on a diskette in a PC floppy drive? And what’s the relationship between formatted … Continue reading

Posted in Floppies, PC hardware | 35 Comments

Kids These Days, Continued

As the OS/2 museum pointed out, many kids these days don’t really know how to properly use floppies. Fortunately, not all is lost and at least some youngsters know exactly what to do with a 3Ā½” diskette. First, firmly hold … Continue reading

Posted in Floppies | 6 Comments

The Central Point Backup Floppy Format

A reader recently asked about the “native” format of Central Point Backup (CP Backup) floppies. Diskettes formatted in this manner are somewhat tricky to work with as they do not use a standard DOS format. A session with Sydex’s AnaDisk … Continue reading

Posted in DOS, Floppies | 27 Comments

Kids these days…

By sheer accident I stumbled on this document. In summary, it’s about a bunch of school kids working on a computer history preservation project and trying to archive a big box of floppies from George Alistair Sanger, a video game … Continue reading

Posted in DOS, Floppies | 22 Comments

The XDF Diskette Format

In 1994, IBM started shipping software with support for XDF, or eXtended Density Format, first in OS/2 Warp and a few months later in PC DOS 7.0. Some of IBM’s software packages were also distributed on XDF diskettes. XDF allowed … Continue reading

Posted in Floppies, IBM | 21 Comments

Detecting Floppy Drives and Media

Detecting floppy drive types and installed media is a far trickier topic than it should have been. In the ideal world, software could determine how many floppy drives are attached, what their capabilities are, and what media is installed in … Continue reading

Posted in Floppies, IBM, PC hardware | 18 Comments