test-drb April 2006

test-drb@ccmp.vtda.org

200 participants
412 discussions

by sb＠thebackend.de

Hi! I got a M7270 CPU module here from my PDP-11/03. It has the tracks to the QBus contacs BC1-BF1 (BDAL18, BDAL19, BDAL20, BDAL21) cut. I of course wondered why one would do that. In [2] I found the following hint: --- II. Restricted Compatibility Options Options in this category do not meet one or both of the requirements for use in a 22-bit system. These options are incompatible with some or all 22-bit systems. ... KD11-HA M7270 LSI-11/2 CPU (16-bit addressing only, and use of BC1,BD1, BE1,BF1 for purposes other than BDAL18-21) --- So I guess someone tried to make the CPU compatible with 18/22-bit modules? What did the M7270 use these pins for? I didn't find any manuals or schematics for the this CPU yet, only for the LSI-11. Could someone point me into the right direction? Thanks Sebastian [1] http://www.bitsavers.org/pdf/dec/pdp11/1103/EK-LSI11-TM-002.pdf [2] http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardwar…

18 years, 3 months

MINC 11

by heronflyinghigh＠btinternet.com

Hi there, I have a minc11 which I must move on due to space restraints it is in excellent condition complete with trolley stand and rx02 drives. I am moving into smaller things and would be interested maybe in a swap. I am particularly interested in Ohio Scientific and have quite a large collection. Any hardware, software or documentation would be most acceptable. Sorry guys I am in the UK so only available there!!!! Regards Graeme -- Internal Virus Database is out-of-date. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.4.0/304 - Release Date: 07/04/2006

18 years, 3 months

Programmer's conundrums

by sdc695＠yahoo.com

Tony Duell says: > Yes, back when engineers actually thought about things and didn't attempt > to 'solve' problems by throwing computing power at them. > -tony I believe that one of the first lessons that should be taught is to program something (of a size greater than a "hello world" program) on an ASR33 or equivalent device. It is a VERY humbling experience. One actually learns to look at programs before executing a compile/run step and takes some thought before doing a "let's try this". I was also told about the firm that went to an automated payroll system. The first candidates (beta testers) were the programmers themselves. Having a built in incentive to "get it right" is VERY motivating. Everyone should keep an ASR33 floating around just to show others. An LA30 is an (almost) acceptable substitute. -- Tom Watson tsw at johana.com __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

18 years, 3 months

WTB: UNIBUS pdp11 handbook

by ISC277＠CLCILLINOIS.EDU

Hi everyone, A simple request: does anyone have a UNIBUS pdp11 handbook that covers 11/34a from between 1979-82 they'd be willing to part with? It's the only handbook I need and don't have. Thanks! Julian

18 years, 3 months

Anyone driving from Boston to VCF East, or from there to the airport?

by dpeschel＠eskimo.com

Hi everyone, I've scheduled an eye checkup in Boston to match the date of VCF East, but I could use a ride from Boston. And I need to get to an airport (probably Newark, I haven't gotten a ticket yet so I have a choice) afterward. Please let me know if either of those match your plans. -- Derek

18 years, 3 months

Tandy Model 16b computers availabe

by Alwrcker82＠wmconnect.com

Hi where in New Jersey (I live near Allentown Pa. (Reading Pa)) I have a Mod 16 no B I would like to see about getting it from you. Thanks, Al DePermentier E-mail: alwrcker82 at wmconnect.com

18 years, 3 months

Tandy Model 16b computers availabe

by cctalk＠catcorner.org

Still have one or two left. Pickup only in Norther NJ. Any takers? Kelly

18 years, 3 months

ISA bus throughput

by mbbrutman-cctalk＠brutman.com

I revived an old 6Mhz PC AT today by removing the original Western Digital based hard disk controller and replacing it with a newer, generic IDE controller. The large boat-anchor class 5.25" full height hard disk had died, and without a suitable replacement a small IDE drive was chosen. The rest of the machine is original, including the EGA card with the extra memory daughterboard and the full slot monochrome card. While discussing this beast, the topic of putting a CD-ROM on it came up. (I would never do such a thing except for giggles.) The topic of the CD-ROM led to a throughput question - could this old monster even do it? As in, is the ISA bus up to reading from the CD-ROM at a reasonable speed? Well, let's go throught some quick math. 6 million clock cycles per second is a lot, but when you consider that each transation on the bus takes 4 to 5 cycles, and instructions take 4 to 5 cycles (average) on a 80285, the throughput might not be so hot. Forget the CD-ROM and let's just pretend it's an I/O device on the bus, like a fast hard disk. Given a PC AT running at 6Mhz, what can reasonably be expected for bus throughput? (Obviously this depends on the loop and the instructions used.) I would have guess 500K or so per second, but now I'm second guessing myself and I'll actually have to write a small benchmark to try it. When writing to a hard disk, would this machine have used a tight processor loop, or would it have used DMA? Under what circumstances would it use DMA to transfer data to a hard disk? And one last question .. Unlike the PC and XT, the AT BIOS handles hard drives. It didn't blink when I removed the crusty WD based controller and replaced it with a no-name WinBond based controller. Does the new IDE controller really look that much like the old controller that the BIOS can't tell? -Mike

18 years, 3 months

Buroughs L5000 available

by dm561＠torfree.net

From: Richard <legalize at xmission.com> Subject: Re: Buroughs L5000 available In article <01C65F0C.7BCFCCA0 at mse-d03>, M H Stein <dm561 at torfree.net> writes: >> Carriage movement literally "stepped" through the "program", and the >> location & length of the pins were the machine language (in the truest >> sense:) instruc tions. Parallel processing of a sort, since each program >> step had multiple instructi ons; i.e. you would read the keyboard, >> add & subtract the accumulator and up to 18 registers, and print, >> all in one operation. >The first VLIW (very long instruction word) architecture? :-) Exactly! A 10 bit decimal data bus and a 20-or-so nybble-wide instruction bus; as a matter of fact, one used a nibbling tool to cut the pins... :) mike

18 years, 3 months

Buroughs L5000 available

by dave06a＠dunfield.com

I was in Montreal today picking up some goodies*, and the guy showed me a Buroughs L5000 accounting machine - too big for me, but he would love it to find a good home. It's BIG - the size of a good sized desk. The schematics that he had with it show a date of 1966... Has a keyboard, what appears to be a printer of some sort, and a paper tape reader. Thats all I know Located in Laval, outside of Montreal, Quebec Canada. Would be a monster to ship! * I know - what goodies? - Complete TRS-80 Model II, main unit, keyboard, drive-expansion unit with three drives - the honkin big TRS-80 "line printer", and a TRS-80 daisy. Tons of software (more than a dozen boxes of disks, many original) and complete documentation (huge stack of TRS-80 binders). - ADDS Mentor 2000 Can anyone tell me anything about this? Worth keeping? (It's fairly big). Got some manuals, but no media. - Some odds & ends. Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html

18 years, 3 months

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test-drb April 2006