The SBC6120 is back once again! (PDP-8 clone KIT)
Bob
Bob's permission. Please direct all discussion to that forum. Bob
requested that I make it VERY clear that more front panels are very
unlikely at this time: it would take at least a hundred orders to make
it possible. And please don't address any questions to me. I'm just
spreading the word for Bob.]
THE SBC6120 IS BACK!
A friend pointed me to a source for still more NOS HD6120 chips and
gently "persuaded" me to order more SBC6120 PC boards. That means the
SBC6120 is back - you can order a bare PC board, a partial kit of the
hard to find parts, or (for a very limited time) a full kit of all
parts, from the web page -
http://www.sparetimegizmos.com/Hardware/SBC6120-2.htm
WHAT'S A SBC6120?
The SBC6120 is a clone of the venerable DEC PDP-8 minicomputer that
you can build yourself, today, using more-or-less modern parts. The
CPU
is the Harris HD6120 PDP-8 chip, which is the same part used in
Digital's DECmate series of computers. The SBC6120 uses an IDE/ATA
disk
or CompactFlash card for mass storage, any ordinary serial ASCII
terminal as a console, and can run OS/8, FOCAL69, and pretty much any
other software that would have run on a PDP-8/E.
Construction is pretty simple with the PC board. Only thru hole parts
are used and no difficult SMT soldering is required. The SBC6120 has
the same footprint as a 5-1/4" disk drive and requires only a 5V power
supply. It's easy to fit the whole thing, including a disk drive, into
an old external drive case. Add a terminal - most people will use a PC
with some terminal emulation software - and you're ready to go.
If you want to get a better idea of what's involved in building one,
there's a complete manual, including assembly instructions and a full
pars list, here -
http://www.sparetimegizmos.com/Downloads/SBC6120.pdf
ORDERING
A bare PC board alone for the SBC6120 is $28 plus $5 for S&H.
A "partial kit" consisting of the PC board, one HD6120 CPU chip, three
64Kx4 SRAM chips, two pre-programmed EPROMS with the BTS6120 firmware,
and three pre-programmed PLD chips, is $150 plus $13 S&H.
You can order either of these options from the SBC6120 web page -
http://www.sparetimegizmos.com/Hardware/SBC6120-2.htm
All shipping prices are for US domestic only - for international
orders please inquire about shipping charges before ordering. All
shipments to California addresses must also pay sales tax.
FULL KITS
People often ask to buy full kits of all the SBC6120 parts, however
I'm always reluctant to sell full kits because of the huge amount of
time required to order all the parts, count them out, and pack them
into
bags. Spare Time Gizmos will sell full kits for the SBC6120, but this
time I've decided to try something a little different.
A full kit of all the PCB mounted parts, except the expansion bus
connector, will be $350 plus $25 S&H. All you'll need to do is build
it, add a terminal, disk drive, and power supply, and you'll be ready
to
go.
If you want to order a full kit, then go to the web page listed above
and order the partial kit. When you complete your PayPal checkout,
include a message with your order saying that you want to buy a full
kit. You'll be charged the regular partial kit price at that time;
I'll
process your order and send you a receipt, and I'll set your partial
kit
parts aside. I will not ship them at that time.
Then, around the middle of January, I'll stop taking orders for the
full kits. You'll get a PayPal bill from Spare Time Gizmos for the
remaining balance, which you'll have a couple of days to pay. I'll
order the parts for the full kits, divide them up, and they'll be
shipped by the end of January. If you don't pay the balance or if you
change your mind, then I'll simply ship you your original partial kit
with no hard feelings.
FRONT PANELS
The front panel kits for the SBC6120 sold out years ago, and I simply
have no parts of any kind left for it. Unfortunately the front panels
are nowhere near as easy to bring back into production as the SBC6120
-
the switches used are special order items, the LED bar and other
mechanical parts were custom machined, and the faceplate itself was
laser cut and silk screened in five colors. If I could find something
like 100 people who wanted to buy one, at a couple hundred dollars for
a
partial kit of the custom parts only, then it might be possible to
have
more built economically.
That seems unlikely, though, so right now Spare Time Gizmos has no
plans to offer the front panel kits again.
Richard B. Gilbert
Nostalgia? The PDP-8 was such a limited machine by today's standards!
The telephone/PDA that rides in my shirt pocket has more computing power
and more memory than any PDP-8!
Dr Ivan D. Reid
wrote in <kYidnccfsrFwCMLU...@giganews.com>:
> Nostalgia? The PDP-8 was such a limited machine by today's standards!
> The telephone/PDA that rides in my shirt pocket has more computing power
> and more memory than any PDP-8!
It still got me a PhD, though...
--
Ivan Reid, School of Engineering & Design, _____________ CMS Collaboration,
Brunel University. Ivan.Reid@[brunel.ac.uk|cern.ch] Room 40-1-B12, CERN
KotPT -- "for stupidity above and beyond the call of duty".
John Crane
"Richard B. Gilbert" <rgilb...@comcast.net> wrote in message
news:kYidnccfsrFwCMLU...@giganews.com...
> Nostalgia? The PDP-8 was such a limited machine by today's standards! The
> telephone/PDA that rides in my shirt pocket has more computing power and
> more memory than any PDP-8!
Yes, Richard. We all know this.
People use them & maintain them for reasons other than sheer computing
power.
-J
rd...@spamcop.net
(snip all the stuff about the SBC6120)
Wow! I've ordered a partial kit, and have sourced pretty well all the
rest...
Looking forward to this...
van...@vsta.org
> Wow! I've ordered a partial kit, and have sourced pretty well all the
> rest...
I've orderd the complete kit... and I would *really* like to get a panel
for it as well. It sure would be nice if we could scare up enough
orders to make another run of them worth it!
Andy Valencia
Marc W. Howard
Did you find a reasonable source for the HD6402? Price?
Marc Howard
rd...@spamcop.net
Not yet...! All suggestions welcome...it's slightly worse here in the UK
anyway, for some of the parts...
Bob Eager
Hear hear. I'd *love* a panel.
I'm not really clear (haven't asked yet) about the availability of the
RAMdisk board....
--
Bob Eager
Bill Gunshannon
I never worked with the PDP-8 at all, but this has got me intrigued.
I will have to take a look. Maybe we can get enough people interested
to make another run possible.
bill
--
Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves
bill...@cs.scranton.edu | and a sheep voting on what's for dinner.
University of Scranton |
Scranton, Pennsylvania | #include <std.disclaimer.h>
Robert Krten
> Andy Valencia
Hey Andy,
I didn't know you were a PDP collector :-) I tried to send you
email but it bounced.
Cheers,
-RK
--
Robert Krten, PDP-8 collector looking for PDP-8 and PDP-8/S
minicomputers; check out their good home at www.pdp12.org
van...@vsta.org
> I never worked with the PDP-8 at all, but this has got me intrigued.
> I will have to take a look. Maybe we can get enough people interested
> to make another run possible.
Note that the "official" Spare Time Gizmos mailing list is hosted on
Yahoo groups. That'll probably be the place where a critical mass of
panel orders gathers.
Andy
Bob
> Note that the "official" Spare Time Gizmos mailing list is hosted on
> Yahoo groups. That'll probably be the place where a critical mass of
> panel orders gathers.
Correct. The person producing them is not monitoring the newsgroups
for order requests. I just cross posted his announcement here for
those not aware of the group or the project. If you are interested in
the SBC6120, order it through the website. If you're interested in the
front panel, contact "the other" Bob, or post to they yahoo group.
rd...@spamcop.net
<foobar_ma...@ieee.org> wrote:
Found a source in the UK - Farnell. About $12.50 in your money...
Marc W. Howard
Yep, I ended up ordering 2 of them (+ 2x of the Harris version of the
82C55) to get up to the 20 GBP minimum credit card order. The only
other option was to order thru Newark in the US, but they charge $20.00
extra because they're buying them from Farnell as well. So since I had
to spend more than I wanted to I ordered 2 sets.
Marc
rd...@spamcop.net
<foobar_ma...@ieee.org> wrote:
I ordered three! I had already ordered the 82C55 from Digi-Key...
I must say that the Digi-Key service seems to be very good. Ordered
Monday, delivered 1115 Wednesday - from the USA.
cjl
> On Thu, 8 Jan 2009 05:52:51 UTC, "Marc W. Howard"
>
>
>
>
>
> <foobar_marc.how...@ieee.org> wrote:
> > rd...@spamcop.net wrote:
> > > On Mon, 5 Jan 2009 05:53:46 UTC, "Marc W. Howard"
> > > <foobar_marc.how...@ieee.org> wrote:
>
> > >> rd...@spamcop.net wrote:
>
> > >>> (snip all the stuff about the SBC6120)
>
> > >>> Wow! I've ordered a partial kit, and have sourced pretty well all the
> > >>> rest...
>
> > >>> Looking forward to this...
> > >> Did you find a reasonable source for the HD6402? Price?
>
> > > Found a source in the UK - Farnell. About $12.50 in your money...
>
> > Yep, I ended up ordering 2 of them (+ 2x of the Harris version of the
> > 82C55) to get up to the 20 GBP minimum credit card order. The only
> > other option was to order thru Newark in the US, but they charge $20.00
> > extra because they're buying them from Farnell as well. So since I had
> > to spend more than I wanted to I ordered 2 sets.
>
> I ordered three! I had already ordered the 82C55 from Digi-Key...
>
> I must say that the Digi-Key service seems to be very good. Ordered
>
> - Show quoted text -
Guys, this is hardware I am hopelessly out-of-step with; I only care
about software compatibility. However, as I understand it, getting a
serial interface on this project was sort-of doable thus allowing it
to talk "to the outside world" without having to take anything apart,
i.e., it can run my Kermit-12 on it, etc.
You have to make a minor patch to Kermit-12 to make it work, but it is
quite well documented; just provide a DEC-like serial port and specify
the device code in the relevant places. However, there is a need for
a one-word patch:
At the time of writing, 6120=DECmate was the rule. As such, if it
found it was a 6120 CPU, it checked for which DecMate it had to be.
It won't work on this machine because it has no DEC compatible [weird]
DecMate ports. The fix is to make a one word change to prevent the
check for the machine being a 6120 and going off onto the DECmate
code, but rather continue in common with the -8/e or 6100 code [which
is fully software compatible with all earlier machine's expectations
for a second serial port, etc.]
Also, this is not the only problem child: CESI made a few Omnibus CPU
boards for the -8/e chassis with the 6120 on them for a one-card [well
two; still needs the terminator!] CPU replacement for the -8/e set
[and no EAE possible]. Thus, the same problem of 6120 does not =
DECmate, etc. But again, these were quite rare and nobody told me to
decouple the 6120 definition from DECmates, etc. I would have handled
it a bit differently. While checking for DM I, II, III, III+ stuff,
failing to find them would be allowed, and then just fall back into
the general PDP-8 code if not DM port hardware, etc.
The reason this can work is that the device 03/04 code I devised [and
is standard in literally all applications within P?S/8 works more
efficiently if not patched for 6120 on anything that is not a DECmate
[and that includes the CESI and the Gizmo] but works even if
accidentally patched on everything. [I still support non-patched code
as long as the hardware you are running on is not a DM. That this is
checked for as a CPU=6120 is not an issue for non-port-related issues;
just that the code self-patches to the mode that is the only way for
DMs to function, and I didn't want to "penalize" all of the compatible
machines needlessly, etc.
This has been discussed elswhere, but the basic problem is that the
03/04 interface is hopelessly broken on the DM and is NOT a CPU issue,
rather the 6121 chips used pervasively in all DMs and nowhere else. I
invented a software alternative to the standard code that will work on
the brain-dead or real hardware. Thus, the logic is that if CPU-6120,
patch the code so it will definitely work, otherwise don't patch it
for compatible machines. The only consequence is that the Gizmo and
that CESI board will get the patches applied needlessly, but it will
work either way anyway. A "purist" would not like the fact that I
applied the patch for the wrong reason, but it still works even when
patched needlessly, etc. Also, I do not have a reasonable way to test
for a DM as opposed to a 6120 CPU in a reasonable amount of space, so
I am not about to rewrite all of that code used so many times just to
correct an unimportant nit-pick. However, in Kermit-12, which is for
OS/8 that cannot even work on a DM [you instead have to use OS/278
which is a demented broken alternative] my code is smarter than the
underlying O/S thus works on all variants of the OS/8 family. [For
example, the code has a file-length restriction that comes about
because it might be running on OS/278, the only family member with a
needless excessive restriction on file opens as compared to all
previous OS/8 systems, etc. Since I am not checking, I always assume
the worst case; this is a rare circumstance anyway, etc.]
So, unless someone has a quick-and-dirty routine that in a few words
of code can check for DM as opposed to 6120, I am leaving it all
alone; the need to customize Kermit-12 was always anticipated; you
still have to provide a customized setting for the second serial port;
the only additional parameter would be where to patch out the DM
check, etc. That code could move and as such needs to be formalized
as a global parameter just like all that is there now. but in any
case, for all of the copies out there, the same one-word patch would
apply.
[Note: I asked for a SMALL quick-and-dirty piece of code; Kermit-12
has the luxury of having scads of once-only code space to check for
all of the DM variants, then give up and become -8/e or 6100-like in
terms of the flow of code in a future release. To fix OS/8 or to
"purify" the otherwise working P?S/8 would need some small code to
make it practical over and above what I did for P?S/8 already; I have
equivalent ideas for OS/8 eventually, but again, nothing that can make
Gizmo boards or CESI boards stand out versus DMs, etc.]
cjl
FrankS
I love Digi-Key. It turns out they happen to use OpenVMS and Oracle
RDB, but I found that out after I grew to appreciate their service.
rd...@spamcop.net
As I just have...thanks! I just decided to buy a load of other stuff,
which is apparently on the ground in Philadelphia right now..here
tomorrow.
warp...@gmail.com
> On Sat, 3 Jan 2009 16:11:51 UTC, Bob <bobkap...@yahoo.com> wrote:
>
> (snip all the stuff about the SBC6120)
>
> Wow! I've ordered a partial kit, and have sourced pretty well all the
> rest...
>
> Looking forward to this...
That's me above...easier to reply via Google Groups as I didn't keep
the message.
Well, the parts arrived, and I've built it! I now have a nice little
PDP-8 clone in a small box, with lots of disk storage on a CF card.
It's running OS/8 nicely...really impressive!