I'm seeking early Intel 4004, 8008 and 8080 chips. The earliest runs had
no date codes, so I'd like specimens with no date codes which will at
least confirm they are from the 1971-1974 timeframe (Intel began stamping
chips with date codes in 1974).
This is for a project I'm working on, and I am only interested in a sale
(sorry, no trades).
If you want me to read your message, please send replies directly to me.
Thanks!
--
Sellam Ismail Vintage Computer Festival
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>
>Subject: Re: semi-homemade micro
> From: Jim Battle <frustum at pacbell.net>
> Date: Mon, 14 Nov 2005 17:57:08 -0600
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Brad Parker wrote:
>
>> Jim Battle wrote:
>>
>>>The original PDP-8 took 10 clocks at 1 MHz to execute one instruction
>>
>>
>> really?
>>
>> I'm probably off, but at a cocktail party I would would have said that
>> some instructions took 8 clocks (f0,f1,f2,f3,e0,e1,e2,e3) and some took
>> 12 (f0-f3, d0-d3, e0-d3).
>>
>> That's according to a recent look at the "blue book", but I may have
>> misunderstood. I did write up some verilog which uses those states and
>> it seems to be (mostly) correct, but it's done all debugged yet.
>>
>> -brad
>>
>>
>
>I'm no PDP-8 expert. My source was this web page:
>
>http://fixedreference.org/en/20040424/wikipedia/PDP-8
>
>"The PDP-8 was a 12-bit computer with 4096 words of memory. It had only eight
>instructions, one full register, the accumulator (AC), and a single-bit
>register, the link (L) bit. The machine operated at a clock rate of 1 MHz, and
>took 10 clocks for each instruction, so that it ran at 0.1MIPS."
That just doesn't sound right.
The 8E which I'm most familiar with is considerably faster than that. Though
the 8S would be slower. I dont consider wikipedia expert here. Doug Jones
and a slew of others have far more complete and accurate sites. Though the
DEC handbooks are not to be trifled with either.
Allison
I recently acquired a HP 9845C option 280 (was looking for it for a
really long time).
The machine is in an overall good condition, however it hangs during
memory test ("MEMORY TEST IN PROGRESS"), even after cleaning all board
connectors, resocketing all ROMs & repeated control-stop's. Before
entering nirvana the printer outputs a couple of memory addresses.
Although lots of defects may be responsible, I assume there is a
combination of both a bad RAM chip and a ROM failure, since a RAM defect
alone should (?) not crash the system during the test.
The printout looks like this:
000000 100112 052525
000000 110112 052525
000000 120112 052525
000000 130112 052525
I guess the first number is the block ID, the next is the memory address
within the block, and the last number is the test pattern, each in octal
representation.
Does anyone have an idea
- how to really interpret the memory test printouts and
- how to check the ROMs for bad data?
Maybe there is anyone out there who did the job to read out the contents
of his 9845 ROMs (they are all in sockets) for a direct comparison.
There is a 98407A memory option installed, and, of course, a bit slice
LPU. So the ROMs work out as:
PPU assembly:
CE1 LB: 1818-1591B
CE1 UB: 1818-1592B
CE2 LB: 1818-0846D
CE2 UB: 1818-0841D
CE3 LB: 1818-0837D
CE3 UB: 1818-0833D
CE4 LB: 1818-1898A
CE4 UB: 1818-1899A
LPU assembly:
CE1 LB: 1818-1506A
CE1 UB: 1818-1502A
CE2 LB: 1818-1507A
CE2 UB: 1818-1503A
CE3 LB: 1818-1508A
CE3 UB: 1818-1504D
CE4 LB: 1818-1509A
CE4 UB: 1818-1505A
Most of them schould be the same as in an 9845B model 200 system.
Thanks for your help
Ansgar
Hello,
Saw your post on cctech mailing list about zapping laptop batteries. I
have an HP laptop battery that I would like to try to zap. Can you give me
details on how it's done?
Thanks,
Andy
>
>Subject: Re: removing parts from PCBs ?JUNK MAIL? 4
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Mon, 14 Nov 2005 12:35:40 -0800
> To: cctalk at classiccmp.org
>
>On 11/14/2005 at 12:05 PM Dwight K. Elvey wrote:
>
>>Hi
>> I don't recommend using an open flame with the oil.
>>I used an electric fry pan. I don't think peanut
>>oil has as low a flash point as many other oils.
>
>I believe that peanut oil has a flash point around 600F; 60/40 solder flows
>at about 370F, so there's a pretty good safety margin, but the oil will
>start smoking at temperatures around 450F.
>
>Silicone oil might be a better choice (it's used a lot in commercial heat
>baths), but it's not inexpensive.
Solder and silicone oils are bad juju. That would result in a
solderability problem.
Myself the oil/fry pan is just duplication a solder pot with a
meniscus (sp??) with the handicap of the oils nasty behavour
and post removal cleaning needs. The solder pot is somewhat
safer if attention is paid to spilling. It also has usefulness
in reloading the board if needed (heat and drop part in holes).
Allison
Hi
I don't recommend using an open flame with the oil.
I used an electric fry pan. I don't think peanut
oil has as low a flash point as many other oils.
That is why it was selected by someone before me
for this purpose. It holds up to higher temperatures
than most oils.
Of course, one should do this outside in a safe area.
One should have a CO2 extinguisher for oil fires or
one rated for them. Don't spray with water if a fire
starts. It would be better to just let it burn up.
I used some tongs and screw drivers to remove the parts.
I generally cut the boards into smaller pieces and don't
completely submerge parts in oil. I watch the temperature
to make sure it is just hot enough to melt solder but
not hotter.
As was mentioned. The oil is really nasty and popping
parts out of boards always splatters some. I used both
a full face shield, goggles, gloves and covering for my
arms. I use the same stuff I use for working with a
large solder pot that we used at a previous company to
solder PC boards by dip soldering. The oil is a little
nastier because to will penatrate cloth easily. Solder
will also if it is moving fast enough but at least it
doesn't just soak though.
Dwight
>From: "Jules Richardson" <julesrichardsonuk at yahoo.co.uk>
>
>Chuck Guzis wrote:
>> On 11/14/2005 at 9:32 AM Dwight K. Elvey wrote:
>>
>>
>>>I've used peanut oil and a fry pan. Then wash the
>>>parts in detergent to remove the oil. You need to wear
>>>gloves and goggles as safety gear. Hot peanut oil
>>>in your eye is not something I'd like to even think about.
>>>Make sure that the assembler didn't bend the corner leads
>>>of the ICs. If they did, you'll need to straighten them
>>>before the oil, using a soldering iron.
>>>It just seems to me that the oil method is a little more
>>>controlled than a torch.
>>
>>
>> That's downright scary--oil fires are nasty. And burns from oil that hot
>> (I've had them from cooking) take a long time to heal.
>
>True, but it is no less risky than normal cooking with oil - plus it'd
>give a much more even heat than a torch. Might give that a try sometime.
>Cooking oil is probably cheaper than torch gas too :)
>
>My only caution would be that gold/ceramic ICs tend to have markings
>printed on with an ink that detergent will remove quite nicely (made
>that mistake once when cleaning a PCB, won't be doing it again :) Other
>components seem to survive such cleanings quite happily though.
>
>cheers
>
>Jules
>
>
>Subject: Re: semi-homemade micro
> From: woodelf <bfranchuk at jetnet.ab.ca>
> Date: Mon, 14 Nov 2005 13:14:09 -0700
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Don North wrote:
>
>> Doing some math, 2GHz/100KHz is 2000MHz/0.1MHz or 20,000. At 6X the
>> cycle count is then 20K/6 = 3333 (not 3.3M).
>> One would think it takes well less than 3000 X86 instructions to
>> emulate a PDP-8 instruction (assuming one instr per clock).
>>
>I would say it takes a few instructions since you have to mask for 12
>bit words, and remember the PC is running windows and all
>sorts of other stuff. The point is the emulation is at least 6x faster
>or more compared to
>the original. Faster may not allways be better for emulation.
With a machine wider than 12 bits the mask is a single instruction AND.
The content of the subfields are more difficult than that but most of
x86s handle bits fairly well.
Allison
>
>Subject: Re: semi-homemade micro
> From: Jim Battle <frustum at pacbell.net>
> Date: Mon, 14 Nov 2005 13:33:01 -0600
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>woodelf wrote:
>
>....
>> Having got a new PC ... 2 GHZ??? who knows the real speed.
>> I have tried Spare time gizmos - pdp 8 emulator ( A minor bug
>> -- with windows how do you get the bell to sound ?).
>> I was running some sort of diagnostics and had the RTC displayed
>> and for about 10 minutes of real time, the clock advanced a hour.
>> That must be at least 6x faster than the real thing on this computer.
>
>If a 2 GHz (give or take) x86 CPU emulates a pdp 8 at 6x, it means either the
>code is inefficient, or the code contains a speed regulator that doesn't work
>properly.
It's inefficient, there was no goal to be efficient only useful and interesting.
>The original PDP-8 took 10 clocks at 1 MHz to execute one instruction, a 2 GHz
>CPU has 20 million cycles to interpret one instruction. So at 6x realtime, the
>program is using 3.2 million cycles to interpret one instruction.
An 8e series was around 1.5uS core cycle time and some instructions took a
few cycles.
However it's timing at the macro level is easy. FETCH, execute as needed.
So to fetch a 12bit word and decide one of 8 major actions is pretty light
on code to do. The next step execute is tempered by addressing but thats
a minor calculation. OPR instructions you need more decisions and they
have a distinct sequence. Then the IOT, again it's all decided by the
device but for codes like 6000Q-6007Q and a few others the path is already
set. EMA adds overhead in all cases.
>Most likely speed and efficiency weren't goals of the emulator, so I bring this
>up not to discredit the program's author but rather to say: don't use that data
>point as anything but a lower limit on what kind of horsepower it would take to
>use a micro to emulate a PDP-8. I imagine an AVR device at 20-40 MHz should be
>able to emulate a PDP-8 at real time.
That may be possible. Keep in mind this type of emulation is almost like
building a microcode sequencer.
An alternate approach is a more hardware (ACC, Link, MQ, MAR, IR ALU
and shifter) and use a micro like 8048(or whatever) to controls the loads
and all and not execute arithmetic logical or register ops in the micro.
Speed there could exceed the 6100/6120 series cmos parts as the micro
is decoding instructions and controling events rather than calculating.
the differnce is your approaching the real thing hardware wise but
leaving out a lot of control logic (sequential or microded hardware).
Allison
The Radio-Electronics articles were written by Peter Stark.
His web site has pretty much the same information that was
in the articles. See http://www.users.cloud9.net/~stark/
and click on the "PT68K" and "68000 Hardware Course" links.
--
Paul R. Santa-Maria
Monroe, Michigan USA
