On 2013-01-06 21:34, John Wilson wrote:
From: "Steve Davidson" <jeep at scshome.net>
The main target for the PDT-11 was RT-11. It was slow. The floppies
spent a great deal of time seeking.
Slow, but still a PDP-11! I had a /150 (plus VT62 and LA36) as my main
computer when I was a frosh at RPI ('84-'85) and it was quite a bit above
average compared to other personal computers at the time (C64, Apple ][,
TRS-80, Atari 800, but IBM PCs were still rare -- so mostly fun toys with
pretty graphics but slow and no disk space and usually no 80-column text).
With 60 KB and most of the floppy/TU58 driver up in ROM space its free
memory was at the very high end of MMU-less PDP-11s -- stuff fits in a PDT
that won't run on a "real" LSI-11.
I ran a PDP-8 at home back then. Boy, those RK05 were fast, and stored a lot. :-)
Also, PAL8 was ridiculously fast... MACREL was a bit worse... But still, compared to what most people played with...
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On 2013-01-06 21:28, John Wilson wrote:
From: Johnny Billquist <bqt at softjar.se>
You must be talking of the PDT-11/150 then. The /110 and /130 sat inside
a VT100 shell. Extremely similar to a VT103 (I actually never figured
out what the difference between a VT103 and a PDT-11/130 is.)
I may be grossly misinformed, but my understanding is that although the
/110 and /130 both live inside a VT100, they're *not* like VT103s, and
have no Q-bus but use a custom CPU board just like the /150 (I doubt it's
the exact same board, but a similar design).
I could have sworn the 110/130 manual on bitsavers (which is misfiled
away from the 150 manual -- I forget where) said so but on a quick skim I
can't find it. The I/O hardware has enough programming differences that
it can't be regular Q-bus stuff, although I suppose they could have made
a whole set of PDT-specific boards.
You know, I had never even thought that thought, but now that you mention it, it makes total sense. I think you must be right.
All the PDT-11 use the same system board. It's not a Qbus at all, in any of them.
That definitely also makes it very different from the VT103.
Thanks for making me understand this. :-)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
From: <Paul_Koning at Dell.com>
BTW, does anyone know why SIMH doesn't support booting from RC11?
I never miss a chance for a plug: Ersatz-11 has RC11 booting.
(The device name is DC:, so MOUNT/DISMOUNT/BOOT work as usual.)
John Wilson
D Bit
From: "Steve Davidson" <jeep at scshome.net>
The main target for the PDT-11 was RT-11. It was slow. The floppies
spent a great deal of time seeking.
Slow, but still a PDP-11! I had a /150 (plus VT62 and LA36) as my main
computer when I was a frosh at RPI ('84-'85) and it was quite a bit above
average compared to other personal computers at the time (C64, Apple ][,
TRS-80, Atari 800, but IBM PCs were still rare -- so mostly fun toys with
pretty graphics but slow and no disk space and usually no 80-column text).
With 60 KB and most of the floppy/TU58 driver up in ROM space its free
memory was at the very high end of MMU-less PDP-11s -- stuff fits in a PDT
that won't run on a "real" LSI-11.
John Wilson
D Bit
From: Johnny Billquist <bqt at softjar.se>
You must be talking of the PDT-11/150 then. The /110 and /130 sat inside
a VT100 shell. Extremely similar to a VT103 (I actually never figured
out what the difference between a VT103 and a PDT-11/130 is.)
I may be grossly misinformed, but my understanding is that although the
/110 and /130 both live inside a VT100, they're *not* like VT103s, and
have no Q-bus but use a custom CPU board just like the /150 (I doubt it's
the exact same board, but a similar design).
I could have sworn the 110/130 manual on bitsavers (which is misfiled
away from the 150 manual -- I forget where) said so but on a quick skim I
can't find it. The I/O hardware has enough programming differences that
it can't be regular Q-bus stuff, although I suppose they could have made
a whole set of PDT-specific boards.
John Wilson
D Bit
On 2013-01-06 21:22, Paul_Koning at Dell.com wrote:
On Jan 6, 2013, at 2:50 PM, Johnny Billquist wrote:
...
I'm even more curious what a PDT-11 optimization is doing in an RSX
driver...was there at one time an RSX product product planned for the
PDT family?
I'm not at all surprised to learn that RSX ran on the PDT-11.
RSX can run on pretty much any PDP-11, as long as you have atleast around 50K of ram. That's about the lower limit, I'd guess. No other hardware frills or features required
RT requires far less. In college, I ported RT to run on the physics department 11/20, which had 8 kW of memory. It required a port because for a disk it had an RC11, which RT did not support. Fortunately, one of the RT authors had come to work at our college, and he helped me a lot. I asked him "why no RC11 support". Answer: "there weren't any around DEC to test it on".
Yes. RT-11 can run on even smaller things, but RSX can really run on much less than most people believe.
Originally that machine ran DOS-11 V4, ugh. RT was a much better OS. We ran RT Basic on it, with mods I made to support all the lab equipment (DR11-A, AD-01, AD-11, KW11-P). Interrupt handlers written in Basic, fun...
BTW, does anyone know why SIMH doesn't support booting from RC11?
Noone have written the code for it? :-)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On 2013-01-06 21:18, Johnny Billquist wrote:
I think only the 11/130 had the TU58. The /110, as John mentioned,
supported only downline loading of the system from somewhere else.
I know I've seen the manuals... Hmm, hang on...
Ah! Found it.
The PDT-11/150 documents sits under pdp-11 on bitsavers.
The PDT-11/110 and /130 sits under terminals on bitsavers. That's why I
didn't find it at first...
And of course, reading through manuals always gives answers...
Yes, it's RSX-11S that was supported on the PDT-11. Page 1-5 of the PDT-11/110 and /130 manual.
Hmm, reading through this a bit more, it would appear that the /110 was intended for RSX, while the /130 was intended for RT-11.
Makes sense, I guess, since you could have a pretty full RT-11 environment there, but for RSX, you'd need some other system for the development, and run the PDT-11/110 with no mass storage, and 11S downloaded at boot, running diskless.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Jan 6, 2013, at 2:50 PM, Johnny Billquist wrote:
...
I'm even more curious what a PDT-11 optimization is doing in an RSX
driver...was there at one time an RSX product product planned for the
PDT family?
I'm not at all surprised to learn that RSX ran on the PDT-11.
RSX can run on pretty much any PDP-11, as long as you have atleast around 50K of ram. That's about the lower limit, I'd guess. No other hardware frills or features required
RT requires far less. In college, I ported RT to run on the physics department 11/20, which had 8 kW of memory. It required a port because for a disk it had an RC11, which RT did not support. Fortunately, one of the RT authors had come to work at our college, and he helped me a lot. I asked him "why no RC11 support". Answer: "there weren't any around DEC to test it on".
Originally that machine ran DOS-11 V4, ugh. RT was a much better OS. We ran RT Basic on it, with mods I made to support all the lab equipment (DR11-A, AD-01, AD-11, KW11-P). Interrupt handlers written in Basic, fun...
BTW, does anyone know why SIMH doesn't support booting from RC11?
paul
On 2013-01-06 21:04, Steve Davidson wrote:
-----Original Message-----
From: owner-hecnet at Update.UU.SE
[mailto:owner-hecnet at Update.UU.SE] On Behalf Of Johnny Billquist
Sent: Sunday, January 06, 2013 14:57
To: hecnet at Update.UU.SE
Cc: Steve Davidson
Subject: Re: [HECnet] DU11 vs. DUV11
On 2013-01-06 20:35, Steve Davidson wrote:
-----Original Message-----
From: owner-hecnet at Update.UU.SE
[mailto:owner-hecnet at Update.UU.SE] On Behalf Of John Wilson
Sent: Sunday, January 06, 2013 14:29
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] DU11 vs. DUV11
From: "Lee Gleason" <lee.gleason at comcast.net>
I'm even more curious what a PDT-11 optimization is doing
in an RSX
driver...was there at one time an RSX product product
planned for the
PDT family?
I've never met a PDT-11/110 in person. The docs say they were
downline-load-only -- so what DID they run? MRRT11?
RSX11S would certainly make sense. Also, DEC dumped a lot of the
PDTs to their own employees, so maybe someone made a few tweaks to
the RSX code for their own evil purposes at home.
John Wilson
D Bit
The main target for the PDT-11 was RT-11. It was slow.
The floppies
spent a great deal of time seeking. They were the size of a small
microwave oven. In software services we would use it to
test patches
to
RT-11 and some of the layered products. I had one for a
time that I
used at home over a 300 baud connection. Tough to say whether the
dial-up or the floppies were slower... :-)
You must be talking of the PDT-11/150 then. The /110 and /130
sat inside a VT100 shell. Extremely similar to a VT103 (I
actually never figured out what the difference between a
VT103 and a PDT-11/130 is.)
If I remember right, the /110 and /130 were TU58 based and the
backplane was a 4x4 18-bit configuration.
I think only the 11/130 had the TU58. The /110, as John mentioned, supported only downline loading of the system from somewhere else.
I know I've seen the manuals... Hmm, hang on...
Ah! Found it.
The PDT-11/150 documents sits under pdp-11 on bitsavers.
The PDT-11/110 and /130 sits under terminals on bitsavers. That's why I didn't find it at first...
Anyway, yes, only the /130 have the TU58. They both can boot using MOP over serial line. It's all in the manuals.
The difference (I suspect) to the VT103 would probably be the network booting capabilities.
In the RT-11 group I seem to
remember one (or more) of those 4x4 18-bit backplanes swapped out for
the 22-bit variant. At least one of those machines used a DSD for a
"real" system disk! :-) It either emulated an RL01 or RL02, and an
8-inch floppy. At that point the TU58's became data "storage" devices.
The PDP-11/23+ that I had in my office used the DSD for RT-11 and RC25's
for RSX-11M. Wow does that bring back memories... :-)
:-)
I've also read about people modifying the backplane for 22-bus Qbus, and then you could throw in an 11/93 CPU, a SCSI controller, and then you'd have a system that really rocks. However, the power supply is apparently a bit marginal.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On 2013-01-06 03:33, John Wilson wrote:
From: "Brian Schenkenberger, VAXman-" <system at TMESIS.COM>
OK, I'll bite. Why is moving a character in the deferred location in
R5 to the stack and then, from the stack to the address in R4 faster
than just going from the deferred R5 location to the R4 address?
I don't know the exact answer, but the I/O page in a PDT-11 is emulated by
an 8085A and it's always super slow. I don't know why DATOB would be any
worse than DATO but if DEC thought it was, I'm sure it's true (it shouldn't
have to be a read-modify-write but some PDP-11 models do gratuitous extra
cycles so it may well be). So this isn't actually a Q vs. U difference, it's
a PDT vs. real bus difference, but the LSI-11 conditionals will catch PDTs.
Anyway, thanks Johnny! Good to know that DU and DUV are 2 for the price of 1.
(And it hadn't even clicked that the thing in a PDT is emulating a DUV, so I
guess it's 3 for the price of 1!)
Just read through the PDT-11/150 manual, and the interrupt fiddling as actually documented. See page 5-19. :-) (Although they don't say *why* you need to jump through that hoop.)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
