Sridhar Ayengar wrote:
Eric Smith
wrote:
Jerome H.
Fine wrote:
I find it interesting that the youngest group of PDP-11 systems
supported
4 MB of memory whereas [...]
I find that statement baffling, as the first PDP-11 to support 4088KB of
memory wasn't introduced until 1975, five years after the introduction
of the PDP-11. I would say that the youngest group of PDP-11 systems
supported 56KB, and slightly less young systems supported 248KB.
I think you two maybe using different definitions of "young".
Sorry about the "Subject" including [SPAM}. I forgot to remove it.
I agree, Eric, that my view of youngest was confusing to you. If I
had provided an example (such as the PDP-11/93), that would have
be easier to understand.
I have six grandchildren. The youngest is 4 years old and the oldest
is 24 years old.
The problem, perhaps, is that the youngest PDP-11/93 is about 20 years
old and the oldest PDP-11/20 is about 40 years old.
More to the point, I was just noting that the STAR100 back in the 1970s
had this 48 bit address for memory when core was so expensive that
4 MB of memory was about the physical limit for that system while at
about the same time, a lowly PDP-11/20 often had just 8 KB or even
4 KB of core memory - yet 20 years later the PDP-11/93 came with
4 MB of memory on the CPU card, but still with a 16 bit program
address even though the physical Qbus address was 22 bits. However,
the 48 bit address on the STAR100 would support 32 Terra Bytes
(I think that is right) of memory which probably almost no systems
today have available - even in disk drives, let alone physical memory.
Jerome Fine
