RSTS/E and PDP 11/23

From: Paul Koning <pkoning_at_equallogic.com>
Date: Mon May 17 16:46:41 2004

>>>>> "Ethan" == Ethan Dicks <dickset_at_amanda.spole.gov> writes:

 Ethan> On Mon, May 17, 2004 at 11:05:25AM -0400, Ashley Carder wrote:
>> I acquired a PDP 11/23 this weekend. It runs RT-11, which boots
>> fine from either the RL01 or RX01s. Has anyone ever attempted to
>> run RSTS/E on an 11/23? I was thinking about attempting to SYSGEN
>> RSTS/E v7.0 on this machine, but in looking over some info on
>> RSTS/E, it does not list the 11/23 as one of the systems that
>> RSTS/E will run on.

 Ethan> The 11/23 and 11/24 have a KDF-11 CPU chip, so it can't be
 Ethan> that. I would _think_ that if you could get a tape controller
 Ethan> that was compatible with whatever RSTS wants (I'd guess "MT",
 Ethan> not "MS", given the era), and you had a compatible disk
 Ethan> controller, an RLV11 or RLV12, I don't know why you _couldn't_
 Ethan> bring RSTS/E 7.0 up on an 11/23.

Interesting point.

Qbus definitely matters for 22 bit support -- I/O addressing is
completely different for 11/70 (UMR and RH70 extended address
registers) vs. Q22 (extended address registers in RLV11 etc.) But
that issue doesn't appear for 18-bit Qbus systems. So yes, you may be
right, RL01 may work via RLV11 simply because it looks sufficiently
like an RL11.

Ditto for single line terminal interface. Not so for muxes; DZ11 is 8
line vs. 4 lines for DZV11.

The "80th anniversary" article mentions 11/23 and RSTS 7.1 around the
same time, but 7.0 a year earlier.

 Ethan> 5MB isn't a lot of room, but it is probably enough. You have
 Ethan> a blank pack for that RL01? What are you using for a v7.0
 Ethan> distro? That, I think, would be the limiting factor.

RL02 is 10 MB, that would be better... The 1982 "system/options
summary" on bitsavers.org shows RSTS for 11/23plus on RL02
distribution. RL01 would be quite tight though certainly a
handcrafted subset of the kit should fit.

     paul
Received on Mon May 17 2004 - 16:46:41 BST