ImageDisk 1.08 posted

[Tony Duell]

> BTW, if someone out there has the HP150 Technical Reference manual
> set, and it says something about what the expected on-disk format is,
> I'd like to know more about that.  Similarly for anyone who has some
> idea what the 9121/9122 drives think about where they're allowed to
> scribble on the disk.

I do have the HP150 technical reference manual and the 150-II update, but 
from what I rmemeber it says remarkably little about the physical disk 
format. I wrote linus programs to read the 9114 disks and there was 
nothing of use in said manual.

>From what I recall, the single and double sided formats are 
somewhat different, though.  

There is also the issue of the bad track replacement. HP reserved a few 
tracks at the end of the disk, and put something on the innermost track 
(79) to indicate that ome of the user tracks was bad and should be 
replaced by one of the reserved ones. Oh, they also wrote the media usage 
count there (that's what causes the drive LED to flash when the disk is, 
in HP's opinion, too old). All this was handled by the _drive_ unit, not 
by the 150, and I've never seen it documented anywhrre. Alas I just had 
to igore it and assume I was using good enough disks that no tracks were 
replaced (this has worked -- so far).

-tony