18 Apr
2005
18 Apr
'05
11:28 a.m.
At 11:04 AM 4/18/2005 -0700, Guy Sotomayor wrote:
--
TTFN - Guy
On Mon, 2005-04-18 at 11:41 -0600, woodelf wrote:
The basic instruction timing on the 11/45, 11/50, 11/55 and 11/70 is
300ns (ie the time it takes for the *fastest* instruction to execute).
There are adders for the different types of memory. On the 11/45,
11/50, 11/55 there is a 0ns penalty for bipolar. It gets slower from
there. I don't have the 11/70 docs in front of me to determine the slow
downs for an 11/70.
One of the other reasons that the 11/45, 11/50, 11/55's are fast when
you put memory in the fastbus is that the fastbus memory is dual ported
so the CPU doesn't slow down when there are other masters on the unibus
(actually they have 2 unibuses but in most applications they are tied
together).
I believe that speed of access to the Unibus on the 11/45 (et al) is also
quite a bit faster than that on the 11/70, although I don't recall the
reasons.
--tom
Allison wrote:
>Sorry, while for those metric the 55 was a tad faster, for IO the
11/70 was
>massively faster. At that time to do large
arrays of data you needed
lots
of fast IO
to disks as you could only works with part of an array at any
time due too addressing limitations of the PDP11.
Umm how about real HARD Numbers when talking speeds. When you measure systems, measure the system not
just the cpu.
Or like everbody does today clock speeds ... with a .3 ns clock
how fast is
REAL memory again?
Ben alias woodelf