FORMAT.COM

The original FORMAT.COM utility supplied with the P112, contains a couple of bugs:

The first one is rather serious: the program formats only the first half of high density disks (such as 1.44Mb 3.5" floppies), the second half is left untouched. This is not a big problem if you just formatted a pre-formatted MS-DOS floppy: the disk will work, although with somewhat reduced performance due to differences in sector interleaving.

To see the effect in action, format a 1.44M floppy, run the POWER.COM utility and try the TEST command (disk surface test) on the formatted diskette. As the test goes by, you'll see that the first half of the disk is read rather quickly, while the second half gets really slow. If the disk you used was instead a previosly unformatted floppy, then you'll get an error right at the middle of the disk.

The second bug was found in the error reporting routine: in the call to BDOS the CP/M function code was passed in register A instead of C. That caused unpredictable behavior when an error happened, often the system would complain about inexistent drives and/or files.

A link to the corrected FORMAT utility can be found in the downloads page, under the CP/M 2.2 section. The package contains both the source code and executable file. An extra cosmetic feature was added: the program shows the track number being formatted and/or verified, so the format process could be monitored.

Last updated 27-Feb-2005