DEC Rainbow disks - help

[Paul Koning]

>>>>> "Tony" == Tony Duell <ard at p850ug1.demon.co.uk> writes:

 >> I just acquired a Rainbow with ~10 boxes of disks.  Most are for
 >> DOS it seems, though some for cpm/86.  Could someone explain the
 >> differences between the types of media meant to run on this puter,
 >> whether it has to do with os, or physical properties (soft
 >> sectored, hard sectored, RX50...). I also have access

 Tony> The RX50 drive (used in the Rainbow, and for that matter the
 Tony> Pro) is a 80 cylinder single-sided drive. The Rainbow (and Pro)
 Tony> have soft-sectored double-density controllers, and store about
 Tony> 360K on each disk.

 Tony> These parameters are independant of the OS used.

That makes it fairly tricky to read, because 10 sectors per track is
not a normal PC floppy mode.  It can be done in DOS (int13 level I/O)
and in Linux (by telling the driver to use nonstandard format
parameters).  I have all that in the "rstsflx" utility for
reading/writing RSTS file systems; I can post selected bits if that's
of interest.

The other confusing point is the addressing: logical block 0 is at the
start of track 1, the sectors are 2:1 interleaved, and physical track
0 holds the LAST 10 logical sectors...

  paul