7 Apr
2013
7 Apr
'13
8:49 a.m.
Ethan Dicks <ethan.dicks at gmail.com> wrote:
allison <ajp166 at verizon.net> wrote:
My fault, I should have been more specific and included: "in terms of
features/peripherals/board count". Also, I was thinking relative to all 11s, not just
QBUS.
What OS to use is yet another undecided question, I haven't even read up on the
options.
I could also just try out some bare metal programming at the ODT for a start.
Seconded :)
Arno
Was it indeed
usual to build such large configurations based on an 11/23 back then?
That was not a small configuration, but it wasn't uncommon.
[data points for system configurations from Ethan and Allison] Not at all uncommon. Usually the disk round out might
have left out the
RQDX or the RX02
but many in the day wanted to move from 8" to 5.25 for space and needed
one system to do both.
OK, some more enlightenment absorbed.
You will want RX50 or RX02 as those were and are
common media.
Either way a RX02 or RX50 was the common simple and
cheap storage
that offered portability.
Mass storage for my system is another area I need to spend more thought on, for now I was
planning to stay with the RL drives I got with the case.
RL packs were over 160$ new and didn't like to
be bounced. FYI drives like RL02 were nearly as expensive as the base
machine ($8-12K).
The drives are not the problem, I have those. I will need to check them out and get myself
some more packs though. On second thought, some kind of floppy might be nice, too, but
that is not a must now.
If pressed for more mass storage, I could always put my QBus SMD controller (and a CMD
Phoenix fixed/removable drive combination I was recently offered )to use with this
machine, although I had got those rather imagined using them with my VSII/GPX.
Its easier to find Dias on RX50 or RX02 though
I've seen them on TK50
but hated loading them form that (slow!).
I do have a TQK(mumble) board already (which was originally also intended for the VSII),
but no drive yet.
> TQK50, DEQNA and RQDX3 at least sound sound a bit
anachronistic
> to me, there surely must have been newer and more powerful
> processors out at the time those became available?
There were - you could get a MicroPDP-11 with a KDJ11,
and lots
of people did, but they cost more. I wouldn't have wanted to run
an RSX-11/M+ system on a KDF11, but I did see plenty of them on
KDJ11 processors (but even more on Unibus machines).
TK50 was tape DLT tape. DEQNA was ethernet, and RQDX3 was
MSCP floppy and hard disk controller.
CPU typically was 11/23+ or 11/73 later on for a price.
So the distinction between the rackmount and MicroPDP/VAX eras wasn't as sharp as I
imagined it.
I have such boards (ok, a DELQA in this case) in said VSII.
I think
I'll have a rather minimal system (KDF11-B, 512kW RAM,
quad SLU, RLV12 + one or drives) for now, not making my first
foray into pdp technology more complicated than necessary.
I would call that a mid-range Q-bus PDP-11 myself, not "minimal".
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory. The fact that it had 4MB of ram was uncommon as back
in the day that was
as costly as the base machine if not more.
I understand that memory was at a premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS systems?
Is BBU supported for the MOS memory options?
I would call
that a mid-range Q-bus PDP-11 myself, not "minimal".
(...)
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory.
Yes, you can even in 16bits. I also have a tiny system using M8186 in a
12 slot dual wide cage running 512KB ram (4 boards), MRV11 (boot),
DLV11J for serial IO, and TU58 for storage. It boots the TU and copies
it to VM: and reboots from there making for a small but very fast
RT-11 system. The OS only use the 28KW and the rest is a virtual
disk (ram disk) big enough to copy the whole base os and a few
useful apps. I think you meant 150MB for RQDXm for its upper limit.
For larger
there were large disks but that was uncommon for Qbus 11s.
RT11 could barely fill (the whole mess) a 20mb drie with much room
left over. For RSTS or RSX a 31mb (RD52) was enough and two
did the trick.
So with just 1-2 RL0x drives, I'm pretty much stuck with RT-11? I've read that it
has a lot in common with later DOS, so that might not even be a bad thing after all :)
larger systems often had mag tape either DLT (tk50)
or 9track for backup and sneakernet (off site or remote systems
before WAN).
No such stuff in sight alas, but ISTR there is some sort of emulator software that makes a
PC act as a serially-attached tape device?
When I was using the BA11N system I described, I owned
an RL01
because I couldn't afford an RL02.
FWIW, I was messing with this system just last month. It's still intact.
Nice to hear that. How problematic are the BA11-N power supplies, BTW?
The system I
still use is the tall (50") rack BA-11 CPU I used in my office
when I was in the Mill (ML03-6/B5) as a utility system for printing and
off line (non VAX work). Still fun to use and I even have a few
uVAX3100s running VMS for it to talk to.
Cool. 
7 Apr
7 Apr
5:33 p.m.
New subject: pdp-11/23 config
On 04/07/2013 08:49 AM, Arno Kletzander wrote:
cables, terminators and those
annoying and scarce drive ID plugs.
If anything the floppy is always a must on my systems as all my diags and
base RT11 systems are on that media (RX01, RX02, RX50, RX33, RX23).
Save it as
loading diags from TK50 is both slow and painful assuming the
system can boot a tK50 (not guaranteed).
There was considerable overlap in uVAX and Qbus PDP-11, they shared all
the same
peripherals. The DEQNA is DELQA for all intents its a generational
thing. The key is
not all of the older PDP-11 software supported the later Qbus
uPDP-11/uVAX hardware.
My fault, I should have been
more specific and included: "in terms of features/peripherals/board count".
Also, I was thinking relative to all 11s, not just QBUS. The unibus 11s tended to
grow larger in IO as the bus speeds supported
higher transfer rates.
Also the larger Unibus PDP11s were faster than the 11/23 and the 11/73
only just caught up.
The older LSI11 systems had it if
there was a call for non volatile
memory, the cost was high.
I happen to have 16KW of qbus core. Also core had a far slower cycle
time than Ram of
the day. Core that ran at 1.5us was fast where ram on the day was
under 1us and dropping.
What OS to use is yet another undecided question, I haven't even
read up on the options.
I could also just try out some bare metal programming at the ODT for a start. Start
with RT11 as a base os and it will allow you to test and get
comfortable at lower
cost to learn. It will be transferable knowledge to RSTS or RSX, may
help with getting Unix
on the machine.
RT11 only need a RX02. one RL02 can hold the entire RT11 install
kit
(EVERTHING).
I run RT11 on TU58 tape (256kb per tape *2), one tape ahs the whole os
with about
30-50K free space the other is not required.
RSTS and RSX may want more than one RL02 for enough space for users.
A RD52 (31MB) is large enough that RT11 barely filled a corner. RSTS runs
many users in that space , RSX will fit with a lot of free space.
Unix V6 fist on a RL02 with about 3-5000 free blocks (block =512bytes).
Compared to VAX/VMS V5.44H barely fits on a 150mb drive with limited
user space.
Command line for both RT and VMS looks the same (DCL).
The base monitor and os can run in 16kb of ram on PDP11.
Yes, it can allow
emulation of the TU58 tape that used a serial interface.
At 38.2K RT11 takes about 5 minutes to boot on a tu58 (real) the
emulated version
is faster (no physical rewind/searches needed) but its still not fast
enough to consider
anything other than RT.
Not bad really but they are aging and until you know the status of what
you get test it!
Seconded :)
Actually I have seven Uvax 3100s, two are m76s, 3 uVAX-2000, one has no
media as
I use it to format media and two uVAX-IIs one in ba23 and the other in a
BA123
with a full rack of disks (RQDX3 RX50, RD4, CMD SCSI and three RZ56s).
The PDP-11 collection includes LSI-11 in BAllN, BA11V with m8186 F11,
three BA11S boxes with 11/2, 11/23, and 11/23+ and a Ba11s in a 50" rack
(the loaded 11/73 system). There is also an H11 (LSI11 with heath IO,
memory,
and box). I keep a Ba23 in a pedestal case uPDP-11 (11/23based, rqdx2
with RD31 and RX50).
The only other DEC systems I have are Robin aka VT180 which is a VT100
with Vt180 board so it can be a complete terminal with Z80 based computer
that runs CP/M.
The rest of my collection of toys are all CP/M systems either S100 or
SBC based.
Allison
Ethan Dicks <ethan.dicks at gmail.com> wrote:
allison <ajp166
at verizon.net> wrote:
In the PDP11 world its easy to build a system that forgets portable IO.
A reminder PDP-11 as not a PC and even a 256kb floppy is viable storage
as RT11 fits on it.
Was it
indeed usual to build such large configurations based on an 11/23 back then?
That
was not a small configuration, but it wasn't uncommon.
[data points for system configurations from Ethan and Allison] Not at all uncommon. Usually the disk round out
might have left out the
RQDX or the RX02
but many in the day wanted to move from 8" to 5.25 for space and needed
one system to do both.
OK, some more enlightenment absorbed.
You will want RX50 or RX02 as those were and are
common media.
Either way a RX02 or RX50 was the common simple and cheap storage
that offered portability.
Mass storage for my system is another area I need to
spend more thought on, for now I was planning to stay with the RL drives I got with the
case.
RL packs were
over 160$ new and didn't like to
be bounced. FYI drives like RL02 were nearly as expensive as the base
machine ($8-12K).
The drives are not the problem, I have those. I will need to
check them out and get myself some more packs though. On second thought, some kind of
floppy might be nice, too, but that is not a must now. If pressed for more mass storage, I could always put
my QBus SMD controller (and a CMD Phoenix fixed/removable drive combination I was recently
offered )to use with this machine, although I had got those rather imagined using them
with my VSII/GPX.
A viable uVAX is more than 150mb, (more like 300-500 for V7),
a loaded PDP11 is 30MB. Just difference is OS utilization.
I would not covet a large drive unless you had the application that
required it.
Its easier to
find Dias on RX50 or RX02 though I've seen them on TK50
but hated loading them form that (slow!).
I do have a TQK(mumble) board already
(which was originally also intended for the VSII), but no drive yet. > TQK50,
DEQNA and RQDX3 at least sound sound a bit anachronistic
> to me, there surely must have been newer and more powerful
> processors out at the time those became available?
There were - you could get a MicroPDP-11 with a
KDJ11, and lots
of people did, but they cost more. I wouldn't have wanted to run
an RSX-11/M+ system on a KDF11, but I did see plenty of them on
KDJ11 processors (but even more on Unibus machines).
TK50 was tape DLT tape. DEQNA was ethernet, and RQDX3 was
MSCP floppy and hard disk controller.
CPU typically was 11/23+ or 11/73 later on for a price.
So the distinction between
the rackmount and MicroPDP/VAX eras wasn't as sharp as I imagined it.
I have such boards (ok, a DELQA in this case) in said VSII. I think
I'll have a rather minimal system (KDF11-B, 512kW RAM,
quad SLU, RLV12 + one or drives) for now, not making my first
foray into pdp technology more complicated than necessary.
I would call that a
mid-range Q-bus PDP-11 myself, not "minimal".
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory. The fact that
it had 4MB of ram was uncommon as back in the day that was
as costly as the base machine if not more.
I understand that memory was at a
premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS systems?
Is BBU supported for the MOS memory options? I would
call that a mid-range Q-bus PDP-11 myself, not "minimal".
(...)
Among other characteristics, I personally think of Q22 as "not minimal".
You can do a lot with RT-11 in 18 bits of memory.
Yes, you can even in 16bits. I
also have a tiny system using M8186 in a
12 slot dual wide cage running 512KB ram (4 boards), MRV11 (boot),
DLV11J for serial IO, and TU58 for storage. It boots the TU and copies
it to VM: and reboots from there making for a small but very fast
RT-11 system. The OS only use the 28KW and the rest is a virtual
disk (ram disk) big enough to copy the whole base os and a few
useful apps. I think you meant 150MB for RQDXm for its upper
limit. For larger
there were large disks but that was uncommon for Qbus 11s.
RT11 could barely fill (the whole mess) a 20mb drie with much room
left over. For RSTS or RSX a 31mb (RD52) was enough and two
did the trick.
So with just 1-2 RL0x drives, I'm pretty much stuck with RT-11?
I've read that it has a lot in common with later DOS, so that might not even be a bad
thing after all :) larger systems
often had mag tape either DLT (tk50)
or 9track for backup and sneakernet (off site or remote systems
before WAN).
No such stuff in sight alas, but ISTR there is some sort of emulator
software that makes a PC act as a serially-attached tape device? When I was
using the BA11N system I described, I owned an RL01
because I couldn't afford an RL02.
FWIW, I was messing with this system just last month. It's still intact.
Nice
to hear that. How problematic are the BA11-N power supplies, BTW?
The system I still use is the tall (50") rack
BA-11 CPU I used in my office
when I was in the Mill (ML03-6/B5) as a utility system for printing and
off line (non VAX work). Still fun to use and I even have a few
uVAX3100s running VMS for it to talk to.
Cool. 
6:20 p.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 07/04/13 5:33 PM, allison wrote:
The older LSI11 systems had it if
there was a call for non volatile
memory, the cost was high.
I happen to have 16KW of qbus core. Also core had a far slower cycle
time than Ram of
the day. Core that ran at 1.5us was fast where ram on the day was under
1us and dropping.
That's odd, I seem to recall my handbooks claiming lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
Can you verify those latencies from your handbook?
--Toby
The fact
that it had 4MB of ram was uncommon as back in the day that was
as costly as the base machine if not more.
I understand that memory was at a
premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS
systems?
Is BBU supported for the MOS memory options?
8 Apr
8 Apr
6:07 a.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 04/07/2013 06:20 PM, Toby Thain wrote:
On 07/04/13 5:33 PM, allison wrote:
The older LSI11 systems had it if
there was a call for non volatile
memory, the cost was high.
I happen to have 16KW of qbus core. Also core had a far slower cycle
time than Ram of
the day. Core that ran at 1.5us was fast where ram on the day was under
1us and dropping.
That's odd, I seem to recall my handbooks claiming lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
Can you verify those latencies from your handbook?
--Toby
That likely was not true for Core on any bus. Core to read it you must
write it back and the
cycle for that is long. MOS memory was far faster and didn't have the
write after read
requirement.
I have little on Unibus as I restrict my collection to Qbus.
Allison
The fact
that it had 4MB of ram was uncommon as back in the day
that was
as costly as the base machine if not more.
I understand that memory was at a
premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS
systems?
Is BBU supported for the MOS memory options?
8:42 a.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 08/04/13 6:07 AM, allison wrote:
On 04/07/2013 06:20 PM, Toby Thain wrote:
I am sure you're right, but I also remember this being quoted the other
way around in the handbook's numbers. (I am sure it's not related to bus
type, just that I was probably working on an 11/34a when I noticed this,
so probably out of a Unibus handbook.)
--Toby
On 07/04/13 5:33 PM, allison wrote:
That's odd, I seem to recall my handbooks claiming lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
Can you verify those latencies from your handbook?
--Toby
That likely was not true for Core on any bus. Core to read it you must
write it back and the
cycle for that is long. MOS memory was far faster and didn't have the
write after read
requirement. > The fact that it had 4MB of ram was uncommon
as back in the day
> that was
> as costly as the base machine if not more.
I understand that memory was at a premium back then.
Out of interest, how common was core memory (H223 and similar) in QBUS
systems?
Is BBU supported for the MOS memory options?
The older LSI11 systems had it if
there was a call for non volatile
memory, the cost was high.
I happen to have 16KW of qbus core. Also core had a far slower cycle
time than Ram of
the day. Core that ran at 1.5us was fast where ram on the day was under
1us and dropping.
I have little on Unibus as I restrict my collection to Qbus.
Allison
10:44 a.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 04/08/2013 08:42 AM, Toby Thain wrote:
On 08/04/13 6:07 AM, allison wrote:
There is one way that _may_ and the PDP-11 may take advantage of it...
PDP11 does many operation on memory (other than instruction fetch)
as READ/Modify/Write and that can be contained in one core cycle.
The ya but... for NPR (aka DMA) each location must be cycled completely
with core and the general access rate is slower as you must finish writing
one location before proceeding to the next.
Allison
On 04/07/2013 06:20 PM, Toby Thain wrote:
I am sure you're right, but I also remember this being quoted the
other way around in the handbook's numbers. (I am sure it's not
related to bus type, just that I was probably working on an 11/34a
when I noticed this, so probably out of a Unibus handbook.)
On 07/04/13 5:33 PM, allison wrote:
That likely was not true for Core on any bus. Core to read it you must
write it back and the
cycle for that is long. MOS memory was far faster and didn't have the
write after read
requirement.
>> The fact that it had 4MB of ram was uncommon as back in the day
>> that was
>> as costly as the base machine if not more.
> I understand that memory was at a premium back then.
> Out of interest, how common was core memory (H223 and similar) in
> QBUS
> systems?
> Is BBU supported for the MOS memory options?
The older LSI11 systems had it if there was a call for non volatile
memory, the cost was high.
I happen to have 16KW of qbus core. Also core had a far slower cycle
time than Ram of
the day. Core that ran at 1.5us was fast where ram on the day was
under
1us and dropping.
That's odd, I seem to recall my handbooks claiming lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
Can you verify those latencies from your handbook?
--Toby
--Toby
I have little on Unibus as I restrict my collection to Qbus.
Allison
12:07 p.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 04/07/2013 03:20 PM, Toby Thain wrote:
That's odd, I seem to recall my handbooks claiming
lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
I don't know from UNIBUS, but the CDC 7600 used 270 nsec core, which, in
1969 was much faster than MOS. The 7600 used a 10-way interleave for CP
memory, which allowed for an effective 27.5 nsec cycle time. The PPs
didn't interleave memory and one quirk of the machine was that it was
possible for very tight loops to overheat a location in core, causing
parity errors. A fix was eventually used that effectively inserted a
"wait state" if any location was hit repeatedly too frequently.
The "exchange jump" on the upper CDC systems (6000 and 7000) used a
read-modify-write cycle to swap the contents of the registers with an
area in memory. It was the fastest way to save and reload the enire
register set (using non-privileged instructions was far more
time-consuming, due to an odd trick used to save and restore the first
register of a set--often used as a quiz to new programmers).
--Chuck
10 p.m.
New subject: Core vs MOS RAM latencies - Re: pdp-11/23 config
On 08/04/13 12:07 PM, Chuck Guzis wrote:
On 04/07/2013 03:20 PM, Toby Thain wrote:
Bitsavers has an 11/40 system manual which lists some timings for Unibus
core:
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/1140/1140_SystemManual.pdf
(4th printing, January 1975)
"MF11-U/UP Memory is a read/write, random access coincident current,
magnetic core type with a maximum cycle time of 980ns and a maximum
access time of 425ns."
However, there is no MOS memory listed for comparison.
According to its system manual, the 11/34 (of which I own a couple)
supports either core (MM11-CP or MM11-DP) or MOS (MS11-EP, MS11-FP,
MS11-JP).
I found the MM11-E core memory manual:
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/memory/MM11-E_CoreMemoryMa…
"cycle time is 1.2?s and access time is 500ns"
According to the MS11-M MOS memory user guide,
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/1144/EK-MS11M-UG-001_Users…
(May 1979)
DATI/DATIP (Memory) Typ. Access time 490ns; Typ. Cycle time 450ns
A later document, MS11-P MOS Memory Technical Manual, Oct 1982, gives
490ns and 680ns for typical access and cycle times (DATI).
Not very conclusive... It seems that some core models were slightly
faster than some MOS models and vice versa.
--Toby
That's odd, I seem to recall my handbooks
claiming lower latencies for
(Unibus?) core than the MOS products in the same range, but don't have
the right handbook to, uh, hand.
I don't know from UNIBUS, but the CDC 7600 used 270 nsec core, which, in
1969 was much faster than MOS. ...
The "exchange jump" on the upper CDC systems (6000 and 7000) used a
read-modify-write cycle to swap the contents of the registers with an
area in memory. It was the fastest way to save and reload the enire
register set (using non-privileged instructions was far more
time-consuming, due to an odd trick used to save and restore the first
register of a set--often used as a quiz to new programmers).
--Chuck
7:32 a.m.
New subject: pdp-11/23 config
On 04/08/2013 05:03 AM, Christian Corti wrote:
On Sun, 7 Apr 2013, allison wrote:
Pedantically correct.
Generally usage is core is magnetic core, ram is mos or other technology.
Used to be a time when core meant system memory regardless of type.
So in 1973 usage your laptop has 4kilomegabytes of core. (or words
depending on organization)
Then again thinking more of the PDP-8 is the whole box the cpu or are
the prime 3 boards
the CPU??
Allison
I happen to have 16KW of qbus core. Also core
had a far slower cycle
time than Ram of the day. Core that ran at 1.5us was fast where ram
on the day was under 1us and dropping.
Core memory *is* RAM.
Christian
4122
days inactive
4124
days old
9 comments
5 participants
participants (5)
-
ajp166＠verizon.net -
Arno_1983＠gmx.de -
cc＠informatik.uni-stuttgart.de -
cclist＠sydex.com -
toby＠telegraphics.com.au