bit addressing, alignment, bus errors, and VM (was Re: PDP-10 arch question) - test-drb@ccmp.vtda.org

26 Oct 1998

...
  Incidentally, a quick quiz.  Assuming all the virtual
address space was
 physical memory and you wanted to make a copy onto a disk drive
 (32 Trillion Bytes - we didn't even have GigaBytes back in 1972, let alone
...
  TeraBytes), how long would a sustained WRITE at 1
MByte/second take?
 Hint: Answer should be in ONE digit of precision along with a time interval.
...
  Eager beavers who want to give us 8 significant
figures of precision
 are disqualified. Just over 1 year
Just under 400 days
Quite a bit under 60 weeks
Just under 13 months ... oops, that was 2 sig. figs.  Rather more than 10
months then.

If you want even sillier units, and at the risk of reviving an off-topic
debate, rather more than 30 megaseconds.

Could these disks do a megabyte per second in 1972?  Sounds rather fast to
me...

Philip.