Subject: Re: Booting DS5000/25 from floppy for installation?????
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: David Burren <>
List: port-pmax
Date: 09/05/1999 11:17:06
With all the talk of installing NetBSD/pmax via floppy, there seem to be
few real datapoints about the hardware, so I'll provide a few more.

Jonathan Stone wrote:
>>On Tue, 31 Aug 1999, NetBSD Bob wrote:
>>> Also, in my dumpster diving last week (actually moo U surplus sales), I
>>> picked up 4 DS5000/25 crates, and  managed to combine the bits to make
>>> one good one, and the rest for spares.  I still need to find a monitor
>>> for it in this weeks surplus sale.  Anyway, like the 3100  with the floppy,
>>> will the 5000/25 boot from floppy for installation?  IFF so, will it use
>>> the same floppy as the 3100?

> The Persoanl DECstation PROMs do not support booting from floppy.
> (Not from docs, but firsthand from someone who wrte the code).
> The floppy was intended for SneakerNet data exchange; the expectation
> was that you'do installs from CD or  net.

> OTOH, the RX33 or whatever-ti-is in Bob's 3100 would do fine, if
> someone cut a floppy image.  As far as NetBD or the PROM care, it's
> just a tiny SCSI disk.
> Simon: does a compressed install (ramdisk) kernel fit into 1.44 meg?
> (we coudl do ustar, but there're so few scsi floppies it hardly seems
> worth it.)

The floppy on the Maxine was a RX23 (1.44M) or RX26 (2.88M).  Probably
an RX23.  The Maxine has an on-board floppy controller and so these
drives were "raw" FDD devices as per normal PC drives.  The versions of
these drives for connection to other machines were SCSI (I have a SCSI
RX26).  The SCSI versions are actually the same drives but with a SCSI
controller attached.

In true DEC style there were many models, one for each machine (the only
difference being the mounting brackets and face-plate).  My recollection
says that the RX3x drives were 5.25" floppies, and I can't recall
whether the RX33 is a 1.2MB drive or smaller.

Now, there may be a little bit of magic which might make things easier. 
My RX26 is made up of a SCSI controller board and a normal 2.88M floppy
drive.  When I connected a normal 1.44M drive the device identified
itself as an RX23.  There is a chance that the RX3x drives (or at least
some versions thereof) used the same controller board and that swapping
the floppy drive for a run-of-the-mill 1.44M or 2.88M will provide an
instant upgrade.

I hope this helps
David Burren