Is it possible (i.e. is the CPU fast enough) to use a TD8-E in an 8A6xx
machine (KK8-E CPU) and the MS8-C memory?
I know the original MOS memories for the 8/A, the MS8-A, were _waaayyyy_
too slow work with the TD8E, but it appears that the MS8C is a lot faster.
Thanks to David Gesswein I found a manual for the MS8-C here
http://www.pdp8online.com/pdp8cgi/query_docs/tifftopdf.pl/pdp8prints/ms8-c.p
df
If I read it right, it seems to say that the MS8C has a cycle time of
1.2/1.4us (i.e. just as fast as the KK8-E) and that it does
transparent refresh (i.e. the refresh doesn't slow down the CPU at all).
And if I'm still reading right, it seems like the only time the MS8C uses
NTS STALL is when the processor first starts up (i.e. goes from the HALT
state to RUN), and that's just to synchronize the transparent refresh cycles
with the CPU. If all that's correct, then it ought to be possible to use the
MS8C with the TD8E.
Does anybody know if this is true before I pull my hair out trying to get
it to work? And if that works, is it also possible to use the KK8-A CPU
(slightly slower than the KK8-E) in the same configuration? I have both CPU
card sets, but the KK8-A takes fewer slots.
Thanks,
Bob Armstrong
Hi all, I'm having a clearout with a pending house move. All these bits
are in Southampton, UK. I'd prefer them to go quickly as one lot but
will consider any and all requests. No guarantee that all this works,
but most of it I've used some time in the past! Please contact me off
list if you're interested.
Sun SS20 doesn't boot. Comes with a pair of Ross 150MHz CPU's and lots
of memory that I never got around to installing.
Sun ultra2. Has solaris 8 installed and works fine. 4GB disk, 200MHz CPU.
Box of sun sbus cards - GX, network, SCSI, etc.
Sun type 5 keyboard and 2 mice.
2 SGI Octanes. Single and dual R10K with SI gfx. Possibly a dual R12K if
you can convince me to get rid of it :-)
Iiyama 19" FST CRT monitor with VGA & 5*BNC connectors. Really, really
nice picture but a few scratches to the glass.
Selection of I-BUS PCI & ISA passive backplanes, including a 20 slot ISA
monster! Most of these are PICMG (think that's it?) mixed ISA/PCI.
DDS1 drive
DDS2 drive
4 SCSI CD-ROMs
2 HP ProCurve 10/100 switches
"Jeta" power supply. pulled from some system it comes with a basic
hand-drawn pinout and does 5V at 80A, 12V at 6A & 12V at 10A
Selection of small (<=9GB) SCSI drives. Mix of 50, 68 & 80 pin.
Right, that's the boring stuff... More interesting is 3 crates from my
rescued Whitecross WX9020 system. I'm keeping this as a working system
with system controller and processing crates but getting rid of the 3
storage crates. Each is a 19" 6U unit and includes 4 disk "modules" (one
of them is missing a module). Each module has 2 disks, each disk is 4GB
and has it's own controller card. Each card has an Inmos T425
transputer, NCR SCSI controller and 16MB of ECC RAM. On the back of each
crate are power boards to take the 48V system power to 5V and ??. The
other cards in the crate I'll keep as spares for the rest of the system
since they're of little use on their own. You could build a 22
transputer network with the disk controller cards - just apply power and
patch in to the links. I've put some pics on Flickr
(http://www.flickr.com/photos/17208732 at N00/sets/72157604779715870/) so
you can get an idea of what I'm talking about :-)
There's probably more to come. Probably some peecee rubbish too!
Cheers,
James
Well,
Some nice items I picked up today:
2 rack config with 1 PDP-11/35 (10" box) & 2x RK05
2x spare PDP-11/35 (10" box)
3x spare RK05
20 RK05 packs
6 Unused RK05 packs
small stack of system documentation
11/23+
No pics, I forgot to take the camera with me.
Ed
I have just about managed to get DECWindows up. All bar one thing.
After logging in as a user in the DECWindows dialog box I get this error
message.
"No license is active for this product" The DW-MOTIF license is loaded
and active.
So what is it referring to to? Answers please
Rod Smallwood
I have a new bounty out for the following items:
1. netDrives Brujo CD/MP3 player
2. AudioReQuest ARQ-1 MP3/CD Player
I'm offering $200 for each unit. They must be working and with original
firmware.
Please contact me directly if you have either of these.
Thanks!
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
Our user group and museum here in NJ -- the Mid-Atlantic Retro Computing
Hobbyists (MARCH) -- owns a Straight-8 as of yesterday morning.
This one is the desktop version (vs. the rack-mount version). Of course,
"desktop" is relative -- it weighs about 250 pounds.
It sat in someone's barn for a few decades, so it was VERY dirty ... but we
put some effort into cleaning off the top layer. Inside we found mouse
nest! But no mouse, whether furry or electronic.
One of the two translucent plastic sides is broken. We plan to fix it, or
rebuild it, or find a suitable replacement.
We also picked up an ASR-33 and a plotter with the PDP-8.
Gotta love transistors, core memory, and flip-chips.
Best of all, we have the story that goes along with the computer -- see
www.resistors.org -- here's an excerpt from the group alumni wiki:
>>>> DEC donated a PDP-8 (original series with 4,096 12-bit words of core
memory), and a model 33 ASR Teletype to the group. We went to Maynard, Mass.
and picked these up from 'the mill' (the original headquarters building) and
brought it back to the barn in someone's VW bus. The computer was mounted on
a pallet with 4 handles so it could be carried like a sedan chair <<<<
So, that's another good reason to come to VCF East 5.0, Sept. 13-14 ....
you'll get to see our desktop Straight-8 with the original accessories (and
manuals and paper tapes, etc.)
- Evan
>
>Subject: Re: 8251 troubles
> From: Brent Hilpert <hilpert at cs.ubc.ca>
> Date: Tue, 29 Apr 2008 00:50:50 -0800
> To: General at priv-edtnaa04.telusplanet.net,
> "Discussion at priv-edtnaa04.telusplanet.net":On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
>
>
>
>Allison wrote:
>>
>> >
>> >Subject: Re: 8251 troubles
>> > From: Brent Hilpert <hilpert at cs.ubc.ca>
>> > Date: Mon, 28 Apr 2008 13:22:08 -0800
>> > To: General at priv-edtnaa03.telusplanet.net,
>> > "Discussion at priv-edtnaa03.telusplanet.net":On-Topic and Off-Topic Posts
>> > <cctalk at classiccmp.org>
>> >
>> >dwight elvey wrote:
>> >>
>> >> Hi
>> >> The routines SETUP and COUT are ROM routines.
>> >> SETUP passes the first byte to the clock generator and the
>> >> remaining to the command port of the 8251. The command/status
>> >> port is 1 while the data is 0.
>> >> COUT sends text to a video board.
>> >> The second COUT never seems to get executed?? I give plenty
>> >> of time between characters because I send then manually.
>> >> The board can do interrupt driven serial but that didn't seem to
>> >> work so I went for the simpler polling method.
>> >>
>> >> DI
>> >> CALL SETUP
>> >> ; .DB $01F ; 9600
>> >> ; .DB $01D ; 4800
>> >> .DB $01B ; 2400
>> >> ; .DB $019 ; 1200
>> >> .DB $0AA ; SYNC
>> >> .DB $0AA ; SYNC
>> >> .DB $040 ; RESET
>> >> .DB $0CE ; 2STOP, NO PARITY, 8BIT , X16
>> >> .DB $010 ; CLEAR ERRORS
>> >> .DB 0
>> >>
>> >> MVI A,$027 ; RTD, DTR AND REC-EN TX-EN
>> >> OUT 1
>> >>
>> >> CALL TIN
>> >>
>> >> CALL COUT ; This works
>> >>
>> >> CALL TIN
>> >>
>> >> CALL COUT ; never gets here
>> >> ......................................
>> >>
>> >> TIN:
>> >> IN 1
>> >> ANI 2
>> >> JZ TIN
>> >> IN 0
>> >> RET
>> >
>> >I have the datasheet for the 8251A but not the 8251 here, so just some guesses:
>>
>> They are the same except for timing and some quirks/bugs.
>
>Well, in general, differential quirks/bugs can go a long way to being a problem.
>There's a fair set of differences listed in the A datasheet.
I know, I was product engineer for NEC when 8251AC was released.
>
>> > - perhaps the 8251 (as opposed to the A) requires the receiver to be re-enabled
>> > (not a full reset) after receipt of each character (an 'explicit ack') (?).
>>
>> Not required.
>
>OK.
>
>
>> > - .. check the error flags to see if a framing error is occurring?
>>
>> You don't have to but it's an idea.
>>
>> > - .. try sending a stream of (best random) characters at full rate,
>> > as opposed to just 2 manually? This might get around some framing
>> > inconsistency or such to at least see if a subsequent character can be received.
>>
>> ??why.
>
>8251A doc says device is picky about seeing the STOP bit.
>Suppose for example, there is an inconsistency between the framing being sent
>and the rcvr cfg, returns first character ok but sends dev into error state,
>and error state does something to subsequent characters returned.
>In general, it might help tease out an otherwise consistent consequence of some
>unexpected behaviour.
It is a bit picky bit then that would creat a framing error and it will still
recieve the next byte. The only "error state" is that the framing flag is
set and if you didn't check it on a byte by bye basis you have no clue what
byte caused it, it continues to recieve (async). Generally the device is
very stupid.
>> > - (may be inconsequential, but in the init sequence the two sync characters
>> > are not preceded by a mode byte (perhaps SETUP does this internally?))
>>
>> Thats required only for SYNC mode not async.
>
>As Dwight has explained they are there for a reliable init, even for async
>mode. I was noticing that it's different than what is suggested for init in the
>A doc, which is to write 3 nuls to the command register followed by a reset
command.
You do that for any 8251 on reset as a matter of course as you may not know
the prior state and you always get to a initial command state. I always
do it but I find for async unless you have a flakey hardware reset it's
not usually required thing for async.
Like I said I use it a lot as I have a potload of them (both A and non A)
>from multiple vendors. I laso have many system that thats the primary
serial IO. NS* horizon, NS* advantage, SBC880 and the companion 5 port
serial card, Vt180 used 4 of them and I have load of them as well. I
do use and program the part still. For Bisync its a disaster, for simple
async the bugs are not near as annoying. I've seen far more problems with
things like toasted 148x drivers/recievers (and DEC 963x) and one end
as 8n1 with the companion system as 7p1!
Other ways to break the part include no baud clock when programming,
chip clock not at least 4.5x the baud clock. There are a few others.
Allison
VCF Midwest happened, and a good time as had (by all?) I've posted a
few pics and various commentary at the 'blog here:
http://silent700.blogspot.com/
Today's post has link to a Flickr set with many more pics, and a short
video. Many thanks to Pat and all others involved in making VCF-MW
happen again this year!
-j
--
silent700.blogspot.com
Retrocomputing and collecting in the Chicago area:
http://chiclassiccomp.org
> Date: Sat, 26 Apr 2008 23:15:41 -0500
> From: Jim Leonard
> I disagree somewhat, if only to present the evidence of the PCjr. Now
> *that* was clearly meant as a home computer (cartridge slots, wireless
> keyboard, small and light, built-in composite video)
I use the introduction of the Peanut as proof that IBM was still
suffering from the shock of having customers flock to buy the PC. As
they discovered, even the unwashed public had its limits as to what
could be passed off as an IBM product. Or maybe it was just the
result of a drunken bet. You forgot the complete lack of DMA and,
shall we say, "anemic" interrupt handling facility?
How about the 1990's IBM "multimedia" computer system? Use it as a
phone answering machine, fax machine, CD player, etc. The only
problem being that you have to leave it on all the time. Toshiba
made a similar blunder at about the same time with its Infinia
machines--only to abandon the desktop business altogether.
Cheers,
Chuck
