Apple FDHD: Formatting PS/2 720K Disks in 1.44 Drives



1) PS/2 machines with 1.44MB drives will, by default, initialize double-
sided dual-density disks to the 1.44MB format when the unsuspecting
user simply types FORMAT A:.

2) IBM recommends against this and refers the user to the MS-DOS
documentation for the proper arcane FORMAT options needed to properly
format double-sided dual-density disks.

3) Most users don't know about any of this and use FORMAT A: just like they
used to.

4) Entire departments are, therefore, evolving collections of double-sided
dual-density disks that are readable on PS/2 machines and unreadable on
Macintoshes (so much for data exchange).

5) Apple's choices are clear:

a) Embark on a massive PS/2 user education program.
b) Make a "best effort" try to read the disks (possibly with an
informative alert).

This is not a problem with AFE. Apple designed the drive to work properly,
and it looks for the "bonus hole" to determine whether a disk is high-
density. The drive design will not be changed.

Installations with PS/2 machines should make an effort to educate users in
proper way to format disks instead of trying to find a patch and jeopardize
their data integrity.

The command to format a DOS disk as 720K in a 1.44MB drive is:

FORMAT A:/N:9/T:80


Published Date: Feb 18, 2012