Subject: Re: Cache for VS3100/M30/M38? [Was Re: VS3100/M76 is FAST!]
To: Brian D Chase <>
From: Anders Magnusson <>
List: port-vax
Date: 06/02/1998 12:15:58
> On Mon, 1 Jun 1998, Allison J Parent wrote:
> > <The 41264 is actually a 64kx4 DRAM.  With four of them, that'd make
> > <128kx8.  Is this possibly the video RAM?
> But with the total of eight, this would make 256KB of video RAM.  Is that
> how much came with the VS3100/M38 on its mainboard?
My video docs says 256K; even if only 128K is used normally.

> > They are video ram.  Cache chips for vaxen would have to be about 8-12x 
> > faster and definately not dynamic(tooslow back then).
> I don't know...  If on some of the CVAX processors the on-chip 1k cache is
> at 90ns, DRAM might not be entirely unreasonable.  DRAM rated at 120ns was
> common around '87 and '88, and I'm sure some exotic 100ns chips may have
> been around somewhere too. :-)
There may be (or not be) cache on the CPU/motherboard. It can be figured
out by the contents of some internal registers. If there is cache; it is
a primary 1K I/D cache and a secondary 64K cache. I think that the cache
is enabled by the ROM VMB, but I'm not sure. Will verify that later.

-- Ragge