On 2019-06-28 15:45, Paul Koning wrote:
On Jun 28, 2019, at 3:07 AM, Johnny Billquist <[email protected]> wrote:
From a hardware point of view, sector header "Word 3" and "Word 4" have
no particular meaning. Just for completeness, can you point me to a
reference where "pack number" is defined or used by the software?
Search for DEC standard 144. If nothing else, I think there is a description in
the RL11 documentation. (Me trusting my memory once more...)
That's different, though. It describes the bad block table, which includes a
pack serial number in its header. Some device types use 144, some do not (in
particular, on RP/RM there is a mix -- RP04/5/6 do not, RP07 and RM02/3/5/80
do). The 144 table is purely a software construct, a bit of data placed by
convention in the last few sectors of the drive and interpreted by the OS. For
example, in RSTS the bad block table is read to mark those blocks as
unavailable, and the serial number is read and displayed during formatting but
not otherwise used for anything.
Right. But that sounded what the OP was looking for. He noted that
serial number and information was written to the pack. The serial number
is never, as far as I can remember, for any disk drive, written anywhere
in any header fields or similar. It's always just on a normal block.
Most packs that have anything reserve the last track or similar for this
kind of information. And that is what DEC STD 144 is about. For disk
packs that do not follow that standard (if we only talk about DEC disks
here), then there is no common area where a serial number will be stored.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: [email protected] || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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