dumb rx01 image question
Paul_Koning at Dell.com
Thu Mar 19 13:54:37 CDT 2009
>>>>> "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...
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