31 May
2014
31 May
'14
4:29 p.m.
On 05/31/2014 09:14 AM, Paul Koning wrote:
IBM didn?t do that on other machines, though. For
example, the 1620
had 200 digit sectors, if I remember right.
And a group mark, so sectors were pretty much anything from 1 digit to
200 digits in length.
Funny sector sizes were found in other machines of
that era as well;
the CDC mainframes had sectors of 322 12-bit words, which were
usually exposed to the programmer as 64 60-bit words, reserving the
first 24 bits for file system control purposes. (PLATO, early on,
did make all 322 words visible because it had its own file system,
but at some point that became a nuisance and there was a whole system
file conversion from 322 to 320 word blocks.)
Was it the 853 disk drive that was set up to take either IBM-compatible
hard sectored packs as well as the 6000 version of the packs with
different sectoring? I seem to recall a 1SP overlay that would allow
853 IBM-type packs to be used on a 6000, but with a considerable loss of
capacity.
Very dim memory of this, anyway.
--Chuck