Slashdot Mirror
Historic Microcomputer Restoration?
Pojodojo asks: "I am doing an independent study next semester with my computer science professor which we decided to call Historic Microcomputer Repair and Restoration. I will be working with such classics as the Altair 8080 and the Apple II. After I have repaired and or restored these machines, I will put them in a display for others to see. I have the opportunity for a modest budget to get equipment to put in the display, and would like to know is, what sort of things would you as fellow comp sci geeks like to see in a Historic Computer exhibit?"
Ascii pr0n, obviously.
*sheesh*
The opposite of progress is congress
I'm not kidding. I remember having a disk of porn for the BBC Micro. That computer only had 32k of ram, and the porn I had was for a mode that used about 5k..perhaps 10, something like that. It was animated too - two frames of it. Amusing.
After all, it was one of the first calculating devices.
.. I don't know the extent to which it fits your definition, but if I was to think of a bitchin' computer (insomuch as it could do some level of computing). It would be an Amiga 500, god I loved that... if you want something a little more in the line of "computer" I would say collosus, the original bletchly park beast... it could still out perform a P4....
*''I can't believe it's not a hyperlink.''
this thing is mroe important seeing as it was used for years for video editing.
But who am I to judge.....
perpetually dwelling in the -1 pits
There was an amazing variety of 8-bit platforms manufactured between 1976-1985, the more you have the better. But take my advice, having refurbished a number of these machines: Plan on buying 3 for every one you get working, Ebay is your friend, no single machine is worth more than $5. You should be able to pick up core cpu/keyboards for $15 following these rules. Use a modern audio cable switch box and a single composite monitor to switch between them- Composite monitors are hard to find and expensive, but many modern cheap 15" TV sets have the correct RCA inputs.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
is to stick with well documented hardware. The two you've picked so far ought to more than fit the bill, but considering you've added "repair" to the title of the class, I assume you'll be doing pcb level hardware repair. This is a LOT of fun and frustration at the same time, but if you start digging into machines that nobody's thought of, cared about, or kept track of over the past 30+ years you probably will start getting into headaches of trying to diagnose some seriously weird bugs. Not to discourage you from this course of action, in fact far from it, it sounds like something I would have enjoyed in my public schooling days (or at least getting credit for it). Find clubs that support the machines and can give you advice, don't try to go it alone, after all, the machines were built by teams, teams should help you rebuild them. Most of all remember to have fun!
Next week's big festivities involve a restored PDP-1.
Their collection of hardware is pretty much unmatched, and is open to the public. What's on display is the tip of their collection's iceberg. Who knows what might be kicking around in the background, just waiting for a small team of geeks to restore?
And conversely, who knows what might be kicking around in your classmates' basements that's on CHM's wish list?
Here's some computers I'd recommend you try to get. Each represents one or more milestones to what we now consider commonplace. (I've left out some of the more obvious ones; please forgive me if I've named some you consider obvious.)
Desktops:
Commodore PET 2001 (color chicklet keyboard).
Sinclair ZX-80/81.
Coleco Adam.
DEC Rainbow 100.
Amiga 2000.
Portables:
TRS-80 Model 100/102.
Osborne 1.
Compaq suitcase PC.
HP 200LX.
Apple Newton.
Toshiba T1000.
A DEC PDP-11/73, my personal favorite.
Probably the easiest computer to rebuild from the classic era as there is only one bus (Unibus), and nothing but traces and some very simple electronics on the backplane. Well that and you could hit them with a hammer.
The PDP-11 series, along with the PDP-8's were some of the first nodes on the ARPANET and you can still get working Ethernet adapters for them.
Hell, I still miss mine (Viper tape drive, RSX/11, RSTS/E 10, BASIC Plus2, 512MB EDSI drive).
(You can still find these things running if you look hard enough... (Try asking old medical/dental offices, most of them ran PDP/11's))
The Geek in Black
I know my BCD's (when I'm Sober)
And a Xerox Star.
What I'm listening to now on Pandora...
Seriously.
You haven't really lived until you've run a multiplication (by repetitive addition) manually on a cardboard computer simulator.
... then you should try to get your hands on a KIM-1, the original testbed for the 6502 CPU. A mid-1970s kit built around Chuck Peddle's baby... now that's historic!
If he were a really old geek he'd have mentioned that he and Ada Lovelace used to sip tea whilst bragging about staying awake until the sun came up weaving towels out of nothing but some thread and the quadratic formula.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
I have a fair amount of, shall we say, junk.
The stuff that amuses folks the most?
Hand modified "rev b" boards.. Every major manufacturer had em. So thick with a spiders web of enamelled wire patching flaws you were amazed they functioned.
Drive platters. I have a few the size of small car tires. People always get wowed when I explain they hold far less data than a floppy disc.
Memory boards. I have a Hewlett Packard board that holds 128 megabytes of memory. At 18x12x2 and a couple pounds, setting it next to a DRAM chip stripped from a modern DIMM usually elicits a 'WHOA'.
.sig: Now legally binding!
People start talking about "historic" computers, and I look around and see I have most the ones they mention still plugged in and running on various tables in my home office.
It makes me feel old.
my old sig is obsolete, and I haven't come up with a stupid enough new one yet
I feel like the altair / apple / C= stuff has all been done over many times....
Someone mentioned the sinclair, that might be interesting, especially if you could find one of the color ones. PDPs and the like fall in with one of my favorites, the Pr1me, as being mini-computers.
How about an Alpha-Micro? It dates to about 1982, so while not _super_ old, it's no spring chicken. The company still exisits in some form, so you might be able to get docs, schematics, etc. And that whole 'write your backups to a VHS tape' trick still raises eyebrows today.
John Soward...University of Kentucky
I would argue a NeXT computer should be part of any display, only because you can show it to people familar with MacOS X and then tell them that this machine has been around since *1990*.
I'm not sure whether this can be easily retrofitted into other computer designs, but one of the coolest things on the LINC--sometimes billed as "the first personal computer"--was the adjustable speed.
The LINC had a pair of dials on it: one was a (continuous) potentiometer, like a volume control, the other was a four-position "decade" switch. The pair of dials joint produced a signal that could be used to make any of a number of front-panel functions auto-repeat at a variable rate. In particular, you could make the "single-step" function auto-repeat. The pot adjusted the repeat rate continously over about a ten-to-one range. Each switch position was a factor of ten faster than the last. The slowest speed was about two per second.
This means that you could make the LINC single-step through its programs at an rate from about 2 to 200,000 steps per second... the later being about half of its full speed.
So, you could take a program... run it at 2 steps per second and watch the lights flash... then gradually speed it up over a five decades to 200,000 steps per second. At 2 steps per second if you watched closely from time to time you'd see one dot on the screen flash momentarily. As you sped it up the, the flashes would occur more rapidly... then you could see it was forming characters... then lines of text appearing at about the speed of a dot matrix printer... then finally a whole screen of flicker-free text.
Meanwhile, the LINC's speaker, attached to bit 6 of the accumulator, would gradually change from ticks to a buzzes to beeps.
I never saw anything that gave you such a feeling for just how incredibly goddam fast a computer was. Even one running at about 0.5 megahertz clock rate.
You actually could build a LINC from scratch, I suppose, since it was discrete components and the design was public domain. But it would be equally interesting to take a "stock" computer of almost any vintage and give it a continuously variable clock, a la the LINC.
"How to Do Nothing," kids activities, back in print!
"you could get a version of MS-DOS that would run on these beasts."
No you couldn't.
Not unless there was an 8088 or 8086 card you could put in them. I guess it is possible such a beast was sold but they would have been rare.
You could get CP/M for them and maybe ZPCR. I also remember a OS called LDOS I think was available as well.
Now the Model 16 could run Xenix which was very cool.
The first computer that Tandy made that ran MS-DOS I think was the Model 2000. It was better than the IBM CP but it wasn't PC compatible and failed in the marketplace.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
I built something like that while in high school, which really dates me.
If you did your repairs and also worked up some rudimentary troubleshooting guide (or better set up a Wiki) for others I think you would be doing a bigger service to the classic computer communtity than just some me-too restorations.
If you want a challenge for a restoration I would go and get a classic system restored and running, then gather a bunch of choice apps for the system and code up some easy front end (on that system or use a virtual drive, something friendlier) to demonstrate the actual programs in an "exhibit environment" (easy reset/reload, nice menu, etc.), a computer that successfully lights READY. is one thing, but one that also presents a menu of some of the popular games or programs of the time to experience is something way better.
"Enjoy what you're doing! If it becomes drudgery, you're doing it wrong!" - Jim Butterfield
The claim probably comes from this incident:
(quote)
A simulation of Colossus which Sale ran on a top-of-the-range Pentium PC took twice as long as the real thing.
or this:
If you wanted to program a modern computer to do what Colossus does, you'd need a 2GHz Pentium to match it.
Don't forget Colossus was massively parallel:
At 5,000 cps the interval between sprocket holes is 200 microsecs. In this time Colossus will do up to 100 Boolean calculations simultaneously on each of the five tape channels and across a five character matrix.
You might want to contact MARCH, The Mid-Atlantic Retro Computer Hobbyist group. They've only been around for a very short time, but they're gathering a lot of informative members. They are running an exhibit this weekend (May 13) in Wall, NJ. Their website is still just basic info, but they have a discussion forum on Yahoo as linked on their main page.