27 May
2005
27 May
'05
11:59 a.m.
>>>> "Allison" == Allison
<ajp166 at bellatlantic.net> writes:
Allison> The big advantage and values of drums was high inerta plus
Allison> parallel heads. Some designs were 16bits wide (maybe there
Allison> were wider) plus timing tracks. So while small ( I remember
Allison> the 128kw swapping drum on the KA10s) they were extremely
Allison> fast.
Some disks had parallel heads too -- the CDC 6638 is 12 bits parallel.
Allison> Of course late in the game was the 32kW RS08 disk for the
Allison> PDP8 systems. Small but very fast word wide storage.
Not fast at all, because that one is NOT parallel -- the RS08 (and its
PDP11 successor RS64, as well as the RF11/RS11) are all serial fixed
head drives. The doc says the RS08 takes 32 microseconds per (12 bit)
word; the RF11 was slightly faster at 15 microseconds per (16 bit)
word.
paul