lunchbox VAXen, was Re: [HECnet] Introducing myself... and my little network

[Gregg Levine]

On Thu, Jun 7, 2012 at 7:55 PM, Dave McGuire <mcguire at neurotica.com> wrote:
On 06/07/2012 07:42 PM, Bob Armstrong wrote:
  Lunchboxes! :-)   And there are images for new boot ROMs available for
those
which will allow you to boot from the on-board SCSI host adapter, ...

   I've heard of this, but I haven't seen it.   As I recall, the onboard SCSI
adapter uses programmed I/O (no DMA!) so it's really slow.   For a TK50
nobody would ever notice, but for the system disk it's a problem.   Better to
cluster boot one, diskless.

  That'd likely be faster!   I'm thinking of the case where one would
want a standalone machine, and the XT2190/RD54 is as capacious as MFM gets.

  Having never run a '2000 via its SCSI host adapter myself, only the
MFM interface, I'd have to wonder whether the bottleneck would be that
PIO-accessed NCR5380 or the 78032 itself!

   FWIW, an RD54 isn't necessary.   The 2000 can easily be convinced to use
_any_ MFM drive, DEC or not.    You can get VMS V4 on a 30 meg drive, maybe
even 20, if you're determined.   Long ago I wrote up a little description of
all the VS 2000 disk formatter parameters, what they meant, and how to fake
them for non-DEC drives.   Google ancient Usenet postings if you're
interested.

  I've had a copy of that archived away for many, many years. :-)

                 -Dave

--
Dave McGuire, AK4HZ
New Kensington, PA

Hello!
I don't know why, but here goes, a while ago there were advertisements
for a thing DEC called the "rtVAX", it was the processor element in a
case about the size of a paperback and mounted on a VME board.

They advertised it as an embedded processor for specialty
applications. The user would, what else? build their code on a host
such as what we are talking about and including the implied
difficulties of debugging it of course, and then deploy it onto the
unit's storage media. And then off it went wearing the code written
and the rest of it on something else.

Why I want one (or two or three or four) is any number of reasons, but
it would be an interesting job getting one of the things working on
our network.
-----
Gregg C Levine gregg.drwho8 at gmail.com
"This signature fought the Time Wars, time and again."