11/45 hack?

[Paul Anderson]

What I was trying to say is that it's not part of the 128 kw or 256 kb
limit of the 45 and is fast.

I don't recall being able to have 2 sets of it. I don't think I've seen one
since I left DEC in the late 70s, but thanks for clearing that up.

Paul

On Sun, Feb 8, 2015 at 4:44 PM, Eric Smith <spacewar at gmail.com> wrote:

> On Sun, Feb 8, 2015 at 2:16 AM, Paul Anderson <useddec at gmail.com> wrote:
> > Think of the bipolar as very fast extra memory. It can sort of act like a
> > cache memory, and can help with processor throughput.
>
> Only if software is carefully written to use it that way. The hardware
> doesn't use it in any way similar to a cache.  It's just a memory
> region that happens to be fast.
>
> > I thought there were
> > 2 controller boards and 4 G401s, but one is better than none. You can
> check
> > that on the top of the processor box in the module chart.
>
> Depends on how much Fastbus memory you have.  There's a controller in
> slot 16 for memory modules in 17-20, and optionally a second
> controller in slot 21 for modules in 22-25.  There's no interleaving,
> so you only need the second controller when you have five or more
> memory modules.
>