test-drb June 2007

test-drb@ccmp.vtda.org

224 participants
486 discussions

by g＠kurico.com

Someone in Austin has a largish collection of old 8bit Atari stuff for sale. Price seems a bit steep to me, but then again maybe I don't appreciate the Atari like I should :) Local pickup only. http://austin.craigslist.org/sys/359890829.html

17 years, 5 months

AT & T 7300 in Kansas (eBay)

by aek＠bitsavers.org

> all my disks (except the hard disk) are bad *snifful*. Have you tried imagedisk and a 360K drive? They are 400k (10 sector, 40trk) I have some discs I can try imaging, though I haven't turned up a set of base discs yet.

17 years, 5 months

Most used toys, was Re: The late, great TRS-80

by ajp166＠bellatlantic.net

> >Subject: Re: Most used toys, was Re: The late, great TRS-80 > From: "Ethan Dicks" <ethan.dicks at gmail.com> > Date: Tue, 26 Jun 2007 16:47:18 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 6/26/07, Dave McGuire <mcguire at neurotica.com> wrote: >> My most >> used classic machine at the moment is a PDP-8/m; I've carved out a >> permanent place for it on my desk. It contains an RX8E which is >> connected to a arallel port adapter based on Chuck Dickman's design, >> which is in turn connected to a small x86 SBC running Linux to give >> the 8/m a disk subsystem. > >Interesting way to do it. How "based on" is it? I know of Chuck's >parallel port adapter, but I'm curious how you've tweaked it. I'm curious too. > >Is the SBC tucked into the /m or is it external? Does the SBC host >your disk images locally, or over a network? > >Given that an RX8E is a PIO device, it makes me think that it wouldn't >be that hard to come up with an OS/8 handler to treat the 12-bit-input >and output ports on a DKC8AA as a disk interface to an external, >modern machine. It doesn't help -8/e/f/m owners much, but the DKC8AA >was a standard peripheral on the -8/a, and normally, unless one is >using the output port as a printer port, unused. I'm sure that will work, many of the OS/8 devices are simple enough and the drivers are small. It would be a great way to get a "disk" on my 8f. Allison >Much to think about there... > >-ethan

17 years, 5 months

Amstrad Master Scan (Australia)

by chrism3667＠yahoo.com

http://cgi.ebay.com/Amstrad-PCW-8256-8512-master-scan-powerful-graphic-tool… seemingly NIB. ____________________________________________________________________________________ Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html

17 years, 5 months

[RESULTS] Re: Best solvent to remove sticky tape residue.

by aek＠bitsavers.org

And what are the results? In order of how effective they were at cleaning the crud: 1. Naptha - excellent, all crud removed easily. http://www.biosci.ohio-state.edu/safety/MSDS/GOO-GONE%20STAIN%20REMOVER.htm Ingredients/Identity Information Ingredient: PETROLEUM NAPHTHA Ingredient: CITRUS OIL

17 years, 5 months

IT Micracle (and I'm still looking for an IBM Displaywriter)

by chrism3667＠yahoo.com

the keyboard to the right reminded me of a displaywriter's: http://cgi.ebay.com/Unique-historic-IBM-Chinese-System-creating-IT-Miracle_… ____________________________________________________________________________________ Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center. http://autos.yahoo.com/green_center/

17 years, 5 months

AT & T 7300 in Kansas (eBay)

by chrism3667＠yahoo.com

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290132606044&fromMakeTra… comes with a box labelled *system software 3.n1*. I previously thought mine had everything - a stack of manuals probably 3' tall. Mine don't have that. And all my disks (except the hard disk) are bad *snifful*. I'm still looking for original images. I do have the media. ____________________________________________________________________________________ Pinpoint customers who are looking for what you sell. http://searchmarketing.yahoo.com/

17 years, 5 months

hat are the really unusual or weird computers?

by roger.holmes＠microspot.co.uk

Just catching up, still about a dozen digests behind! > What are the most bizarre, way-out or just plain *different* machines > that folks have seen? Well how about a machine with a normal instruction set but no program counter? It has a 48 bit word, and most instructions are 24 bits, with a few 48 bit ones. It has three 'Control Registers', and normally at least one has a unconditional absolute jump instruction in it, which jumps to the next word. After a single length instruction is executed, it gets one added to it (in binary coded decimal), and it gets moved from control register (CR) 1 to CR3. At the same time, CR3 goes to CR2 and CR2 goes to CR1 ready for execution. If it is a jump instruction things are a bit different, the original CR2 and CR3 are saved in the 'A' register and the value at the address specified in the jump instruction gets put into CR1 and CR2 instead of the old values of CR2 and CR3. CR1 still gets incremented and put in CR3. Simple enough so far, but what about conditional jumps and procedure calls? On a condition jump where the condition is true, the top 8 bits of the instruction get cleared, which makes it into an unconditional jump. A procedure call (which can be conditional or unconditional) is just a jump instruction. What makes it a procedure call is in the function itself. It stores the A register in memory, usually at the word after the end of the routine. When the program reaches it end, it executes this word. If the procedure call was in the second (bottom) half of the word, then it will execute a jump instruction to the word after the word where the function call was made from. If the procedure call was in the first (top) half of the word, then it will first execute what had been in the second half of the word, which could itself be a procedure call, which actually works out just fine if you think about it. Now I hear your objections - no recursion, no re-entrancy etc. But this machine had no interrupts, and if you really needed recursion then you could implement a stack in software and save the A-register in that stack. Anyway, with a maximum of 2000 (yes 2000 not 2048) words of store and overlays on drum backing store or magnetic tape, programs could not be huge anyway. Other weirdness: pound shillings and pence arithmetic in hardware with a variable ten shillings position register, so than digits to the left were decimal (radix 10), the addressed digit was radix 2, the next digit was decimal, the next was radix 12 and the rest were decimal. This even had a multiply instruction which could multiply a LSD amount by a decimal amount. Division was all in software. The machine was designed in the late 1950s, first delivered 1962 (such a long gestation that it was the only ICT/ICL machine where all the promised applications software/libraries was ready before the first machine shipped). It a collaboration between the British Tabulating Machine company (which had recently given up its rights to use all IBM designs and patents!) and the British General Electric Company, Telephone division based in Coventry. By the time it shipped, BTM had become ICT (International Computers and Tabulators) and went on to be merged with almost all the other British computer companies to become ICL (International Computers Ltd). Somewhere between 155 and 200 of these ICT 1300 series machines were made up to becoming obsolete in 1965. As I understand it, in 1965 there were 950 computers in Britain, so a large proportion were of this type, though of course some were exported. Another weird machine, the CHLL, Compacted High Level Language computer. Executed Coral 66 (a real time variant of Algol 60) in microcode. It was a 24 bit machine but instructions could be any multiple of 3 bits, and could start on any 3 bit boundary. Top 21 bits of program counter were word address and the bottom 3 bits were the 3 bit byte address within the word. The machine was flyable, but otherwise a normal computer which could have a teletype, paper tape reader and punch attached. Only two made (one ground prototype and one flyable).

17 years, 5 months

WANTED: TRS-80 video/disk interface <-> model 100 cable

by dm561＠torfree.net

-----------------Original Message: Date: Mon, 25 Jun 2007 21:15:11 -0700 (PDT) From: steven stengel <tosteve at yahoo.com> Subject: WANTED: TRS-80 video/disk interface <-> model 100 cable I have the TRS-80 disk/video interface module, but not the cable to connect to my model 100. Does anyone know how to make one? Thanks- Steve. -----------------Reply: It looks simple enough; just take a 40c IDE HD cable and crimp a 40-pin DIP header on the end... But there's a catch: The connectors will not be offset the standard way relative to each other, i.e. you need to swap the even and odd pins somehow. There are two ways of doing that: 1 - Separate all the wires at one end and swap them when you insert them in the connector; put the striped wire in the second slot, the second in the first, the third in the fourth, the fourth in the third, etc. 2 - Crimp the 40-pin DIP header on an IDE cable without swapping; Get a second IDE cable and a set of 40 header pins such as you would find on an old motherboard (make sure they're long enough) and use them to connect the two cables; this will give you the offset and also a way to connect and dis- connect without opening the cover and possibly damaging the delicate 40-pin DIP header. If you make the M100 cable the right length you can fasten the header to the back of the M100 with DS tape and effectively have the same setup as the M102 & 200. If, as usual, I haven't made it very clear, contact me off-list & I'll send you some pictures. BTW, if you're new to the M100 world, check out club100.org and the user group there; lots of folks always willing to help. mike

17 years, 5 months

spectrum hidden menu on reset

by aliensrcooluk＠yahoo.co.uk

hi, i have a spectrum 128K +2 which has been put somewhere "safe" by my parents. When i used it and hit the reset key (by the joystick ports on the left side) i would sometimes end up a secret debug (?) menu. I never altered anything when it came up (a mate did and ruined his spectrum!) and simply pressed reset again. Im just curious to see if anyone knows how to make it appear on reset. What sort of things did it alter? - Andrew B (via mobile phone)

17 years, 5 months

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test-drb June 2007