> From: "Rob Jarratt"
> Thanks for this info Noel.
Sure; I figured it would be useful to someone, glad to know it was.
> So it sounds like I would need the C-230-S-124. ... My metalworking
> abilities are limited.
If you don't want to have to do any mods, the C-230-S-122 is a straight
bolt-in, albeit $30 or so more than the -124, which requires..
> I am not clear from the picture you linked to, what the modification is?
Drilling the two holes.
So, you have an RK05 drive, but you're missing the slides to mount it?
Your troubles are over (sort of :-).
It turns out the slide DEC used was the General Devices 'Chassis Trak'
C-230-S-122 (22") - and those are still available (e.g. from Newark). They're
somewhat pricey - the -124 (24") is slightly cheaper, and can easily be
modified to fit an H960, viz:
The one in the image actually came off an -11/05 in a 10-1/2" box; the 3-3/8"
outer slide pair from the RK05 slides does in fact fit the inner slides (i.e.
the part permanently fixed to the box) used on a lot of BA11 boxes.
One hitch: the location of the safety latches (the 'buttons' on the inner
slides that pop out through holes in the intermediate slides) is different on
most of the BA11-K inners (on the three BA11-F's I've looked at, they do
match), and so the latches don't work. (Unless of course you make the correct
hole in the intermediates, or drill new holes in the inners that come with the
slide set, to match the mounting holes on the BA11-K, and use them instead.)
So, better than nothing, if you have BA11's (or similar) and don't have the
outer slides, to mount them.
The old extended/expanded memory manager for DOS. Anyone remember?
I'm playing with bootable USB keys with PC DOS 7 (and DR-DOS 7 to follow).
I have it working and booting now, but I'd like to disable QEMM's
memory check on startup. I'm sure there was a switch, but I can't
remember it. Even with just -- "just" -- 4GB of RAM it takes quite a
If anyone knows of a place where there's a summary of QEMM's
command-line switches, that'd be great. I have found some manuals but
I'm using QEMM 9, the last version, for Win9x.
Liam Proven ? Profile: https://about.me/liamproven
Email: lproven at cix.co.uk ? Google Mail/Talk/Plus: lproven at gmail.com
Twitter/Facebook/Flickr: lproven ? Skype/LinkedIn/AIM/Yahoo: liamproven
UK: +44 7939-087884 ? ?R/WhatsApp/Telegram/Signal: +420 702 829 053
> From: Kip Koon
> I was initially thinking of a strictly software only solution
Whatever you eventually do in the way of hardware, it might be a good idea to
start with this. You can get familiar with whatever OS you decide to go with,
and get used to its tools, get to know the instruction set of that
machine, etc, etc.
So then, if you do do a hardware project, it won't be such a big gulp, and
you'll have the knowledge base covering all the above already there to draw
> which still presents a problem for me and that is which PDP do I teach
> myself and set up.
Probably the way to answer that is, if you're going to build hardware at some
point, a combination of 'what's out there that I can get to talk to', and
'how complicated a beast are we talking about'.
For the first, there's a lot of QBUS stuff around, some UNIBUS, and basically
zilch on the PDP-10 or PDP-15 front. For the second, most -11's (both QBUS
and UNIBUS) are relatively simple and straightforward. Any kind of PDP-10 is
pretty complex (depending on if you emulate the original busses, or not).
> 3rd, and this is a big factor in the choice of DEC PDP computer to pick
> for simulation or emulation and that is the small cash flow and itty
> bitty storage space I have available to me.
> The choice so far it seems is the PDP-11/70.
If all you're doing is simulation (software), the -11/70 would be fine. It's
no more work to set up than one of the other timesharing-capable models; it's
only slightly more complicated than say, an -11/45, _from the programmer's
point of view_ (there's a UNIBUS map as well as the usual memory mapping
hardware), but if you're running an existing OS, that should not affect you.
> Remember I still have no idea ... what boards and peripherals
> a PDP-11/70 consists of.
Hardware-wise, the -11/70 could be a complex project - it depends on exactly
how much you try and emulate, a full emulation could be a very complex
The thing is that while the /70 looks to the programmer a lot like one of the
simpler models, the hardware is quite a lot more complicated: there is a
cache, a separate memory bus, high-speed I/I controllers with their own
special bus to the devices (MASSBUS), etc. It's basically an -11/45 with a
bunch of extra stuff glued onto the sides of it to boost the performance; the
board count went from 10 (w/o floating point, which adds an extra 4) to a
minimum of of 16 (w/o FP), plus 4 for each high-speed I/O controller (up to
Now, if all you're doing is emulating the system, _without_ providing any of
the busses, no problem; all that complexity is hidden inside the simulator.
But once you start emulating real busses (i.e. to be able to plug in real
hardware) - whole different kettle of fish.
> From: Kip Koon
> f I were to have to decide on just one model DEC PDP system to run in a
> DEC Emulator, which one would be the most useful, versatile and has the
> most software available for it?
To echo what others have said, when you say 'emulator', do you mean hardware
(the usual meaning of emulator), or software (which would be a simulator)?
And if you mean hardware, are you going to emulate the bus as well?
Having said that, I think you should ask yourself 'what do you want to do
with it'? The thing is there are a lot of DEC machines which are
'interesting', and have a lot of software available for them: the -8, -10,
11, -15 and VAX (dunno if you consider that a 'PDP') are all in that category.
> I hear a lot about the PDP-11. I found out that there were 16 major PDP
> models at one time so I'm not too sure which one to pick.
They aren't really that different; many of them are more 'the optimal
technology to implement in' changed over the (fairly) long life of the
architecture, so many of models are where an earlier one was replaced by a
more cost-effective equivalent. E.g. for one 'class', the /20 (TTL SSI) was
followed by the /05 (microcoded TTL SSI), and then the /04 (TTL MSI), and then
the /03 (LSI); in another the /40 was followed by the /34 and then the
/23. Etc. There are really only 3 kinds of -11:
- Those without memory management (the /20, etc)
- Those with 'simple' memory management (the /40, etc)
- Those with 'complex' memory management (all the others)
Simple software will run on all three; more complex (e.g. Unix) only on the
> Back in the day when Bill Gates and company 1st started out
> ... a B/W photo of a young Bill Gates bending over the operator at what
> looked like a very small computer. Maybe it was just a terminal. I
> don't remember. I understand they did software development on a DEC PDP
> of some sort.
The very earliest version of their BASIC was done on PDP-10's running TOPS-10
- first the one at Harvard, and then some commercial time-sharing system in
the Boston area.
> I have many projects in the works already so I decided to setup a
> software emulation of just one of the DEC PDP models.
OK, so it's going to be just running a simulator?
> I have heard a lot about the PDP-11 which if the information I read is
> correct was 16-bits. in the world... The PDP-11 is the model I hear the
> most about.
Well, for good reason, I think.
It was at one point (1980), the best-selling computer, and really made the
minicomputer (yes, I know the -8 was the first successful mini, but their
size/computing power range was a lot smaller than the -11, and so it didn't
have as widespread a utilization as with the -11).
It's also the machine that Unix was developed on, so if you want to play
around with the 'classic' early Unixes (e.g. Version 6), you'll be wanting
to go with the -11.
Finally, it is to me the finest architecture ever, in terms of elegance, and
bang/buck - the power they squeezed into a 16-bit instruction is pretty
mind-blowing. If you want to see a really elegant design, look at the -11. A
lot of later architectures stole a lot of ideas from the -11.
If you want to go the -11/V6 route, there are instructions for doing
and I have a very detailed page for doing so with the Ersatz-11 simulator
(which is _very_ fast, and easy to work with), with a lot of useful pre-built
disks, and tools, here:
The other one I would point to as 'interesting' is the PDP-10, _especially_
if you run ITS on it. There's a very complete and detailed page here:
for bringing it up under SIMH. There's also KLH10 as a simulator, which I
know a lot of people like for running ITS; instructions here:
which has a lot of detail about how to get things running _on_ your ITS once
you have it up.
Please let us know what you decide... :-)
Here is the latest batch of items up for sale. Full running list with
updates are here:
New items for October 26, 2017:
3Com Corp IE Controller (1982) ASST 0345-03 REV J - very early(?) IBM PC
ethernet controller; BNC and AUI connectors; good condition, maybe probably
still works [
3Com Etherlink II ASSY 2227-00 REV 08 - 8-bit PC ethernet controller; BNC
and AUI connectors; excellent condition
HP 82335 8-bit HP-IB ISA board - excellent condition - $35
Future Domain TMC-850MER "Apple Signal Port" 8-bit ISA SCSI board - has
socket for BIOS EPROM; comes with 50-pin ribbon and Y-splitter power
cables; like new; [http://www.vcfed.org/forum/archive/index.php/t-9546.html]
Unpopulated (New Old Stock) Motorola MC68000 Educational Computer board -
like new condition - $20 shipped anywhere in USA
Sirius Systems Tech peripheral mainboard - for Victor 9000/ACT Sirius 1
computers; excellent physical condition, unknown functional condition - $13
shipped anywhere in USA
Panasonic Interface Adaptor RP-K100 - parallel port interface for Panasonic
word processor(?) - $5
Kroy Digital Cassette Drive Cat. No. 1674400 "290 Keyboard" - digital
microcassette data drive; 34-pin dual row connector; includes digital
microcassette tape - $15
APCON ACI-2016 SCSI Booster - 68-pin SCSI booster, w/power supply - $10
Advanced Electronic Applications PK-64 PAKRATT-64 - packet radio modem for
Commodore 64; excellent condition - $60
Remex 5.25" drive - inside external enclosure with power supply and 34-pin
connector; excellent condition inside and out - $15
HP 82950A Modem - includes severely water damaged but mostly readable users
manual - $45
HP 00085-15001 Mass Storage ROM - HP-85 mass storage ROM, allows HP 85A to
connect to disc drives - $25 shipped anywhere in USA
Avatex 1200HC 300/1200 external modem - $5
Atari SC1224 (Version 2) color monitor - powers up, has raster, do not have
cable to test - $70
Atari SH305 MegaFile 30 - contains Seagate ST-238R hard drive; powers up,
drive spins up, sounds healthy; case was slightly hacked by a less than
skilled hand to add status LEDs to the front as well as a slot for a 3.5"
removable drive (not present; includes custom internal 34-pin slot
connector to external DIN connector cable) - $50
Atari 1064 - 48K parallel port memory module for Atari XL series - $20
Atari SX212 Modem - for IBM PC and compatibles; in original box with
manual, power supply, and data cable
BMUGNET adaptors for Macintosh - made by Bay Area Mac User Group;
pre-Farallon PhoneNet adaptors; works similar to Apple LocalTalk - 2/$10
Sun Type 4 optical mouse - $5
Commodore 1531 Datasette - $15
Plus Development Corp. Impulse dual external hard drive unit - same maker
as Plus Hardcard; includes (2) Conner CP-340 40MB RLL drives, powers up and
drives spin up with healthy sound; unable to test further; requires DB-19
cable and PC interface board to be fully useful - $20
DSP 225 Tempest InkJet Printer - HP ThinkJet Model 2225A (HP-IB interface)
fitted inside an all black TEMPEST resistant enclosure, fine working
condition - $75
Computers and Such
Tektronix 4050 - complete working system in excellent condition with
manuals and software on QIC
Apricot F1 - CPU only; powers up, blurts out some strange "beep" and seeks
a boot disk; (2) internal 3" drivesl unable to test further
Motorola Envoy - (3) units with (1) charge station and extra battery
Commodore 16 - untested - $30
Osborne 1 - original tan case; fairly low serial number (A01284); powers
up, screen is good, tries to boot from disk drive; very good cosmetic
condition with some scuffs, leather handle is broken - $160
HP 7475A Plotter - full complement of pens are mostly dried out but it
performs the demo function admirably; excellent condition - $85
Lynx 460 floppy disk drive exerciser w/User's Manual and Xerox Supplement -
Atari Mega ST4 - powers up, seems to boot from the floppy drive, no monitor
cable so unable to test further; includes Practical Solutions Tweety Board
(adds true stereo) - $250
Radio Shack TRS-80 Model 100 - works great; very good condition with minor
yellowing and a couple scratches; includes form fitting faux leather case
in excellent condition - $40
Dolch Logic Instruments 9604 uP Trace Unit - logic analyzer module for
National Semiconductor NSC-800 microprocessor - $15
Tandy data cable - 34-pin slotted connector to Centronics male connector,
approx. 10' - $5
As always, please send inquiries to me directly via e-mail at for best
Beginning of the 70's I was using a pdp-10 at TSL (Time Sharing Limited, UK)
over a phone line writing logic simulation software in Fortran. Remember it
fondly, especially the number of times I needed to redial in and try to
reconnect to my session. Still smell the teletype. Cost about ?10 for the 20
seconds cpu-time or so just to compile the program!!!
Roll on a few years and I was actually at the console of a 10 at Smiths
doing IC layout graphics interactively on their Lady Jane suite. What a
great single-user machine!
(and I still remember my username and password from TSL, typed it so often
it burned in).
> -----Original Message-----
> Date: Tue, 24 Oct 2017 18:42:42 +0100
> From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
> To: "'Dave Wade'" <dave.g4ugm at gmail.com>, "'General Discussion:
> On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org>, "'Kip
> <computerdoc at sc.rr.com>
> Subject: Re: Which Dec Emulation is the MOST useful and Versatile?.
> Message-ID: <003101d34cef$7eca53c0$7c5efb40$(a)ntlworld.com>
> Content-Type: text/plain; charset="us-ascii"
> Ah the PDP10! Although the very first computer I used was a PDP11, it
> was so briefly that I really consider the PDP10 (in DECSYSTEM-20 form)
> to be my first computer. It is easy to emulate in SIMH, although the
> SIMH emulation is of a less capable processor (KS10) and I think KLH10
> is the best emulator for that (but I have never used it).
Here is an interesting mini-documentary on the fight Gilbert Hyatt (patent
holder for the concept of the microcomputer) had with the Franchise Tax
Board of State of California: