dumb rx01 image question

[Paul Koning]

>>>>> "Don" == Don North <ak6dn at mindspring.com> writes:

 Don> The 'even/odd-skew-by-6' algorithm mentioned in a previous email
 Don> is what I found works for XXDP. It is probably the DEC
 Don> 'standard' for RX01/02 drivers.

I would assume that is the case.  I found it in a RSTS driver, and
the that that two very different systems share a mapping function
suggests it's a DEC standard.  (DEC certainly tended to standardize
this sort of thing company-wide.)

FWIW, RX50s are interleaved and skewed, too.  The track length is 10
so the groups are logical sectors 0-4 and 5-9.  Also, the first group
is the odd one (so logical sector 0 is physical sector 1).  Track skew
is two sectors, bnot 6.

Finally and most strangely, while on RX01 track 0 is unused, it isn't
on RX50.  What happens instead is that it's the last track.  So
logical block 0 is track 1, sector 1, and logical block 799 is track
0, sector 4.  Go figure...

   paul