test-drb November 2017

test-drb@ccmp.vtda.org

126 participants
149 discussions

RK06 Data Cartridges / Alignment Cart Available (and other stuff)

by billdegnan＠gmail.com

My last email was unclear...I have a few RK06 Data Cartridges and an Alignment Cart Available. Contact me privately if you have an RK06 drive and you're looking for carts. They look like RL02's maybe a hair thinner. I paid a small amt, and I am looking to be reimbursed for the cost. I have no RK06 drive. RK06 cartridges are NOT compatible with RK07's according to the manual. If you're in the Landenberg, PA area stop by, At some point I will publish a list of other DEC items I have in clean organized storage. Bill

7 years, 1 month

Which Dec Emulation is the MOST useful and Versatile?

by jnc＠mercury.lcs.mit.edu

> From: Jon Elson > I'm not sure the original DEC PDP-10 (KA-10) used microcode No, it didn't; in part because it pre-dated fast, cheap ROMs (the development of which was a considerable task in the /360 project - the wonderful "IBM's 360 and Early 370 Systems" covers this is some detail). The KA10 is built out of FLIP CHIPs which carried individual transistors. Another fun KA10 fact: it used 'hardware subroutines' - i.e. a clock pulse would get to a certain point, and get conditionally diverted through some other circuitry, later to come back and continue where it left off. Whee! Noel

7 years, 1 month

DEC BA350s, BA356s, drives, tapes, etc

by useddec＠gmail.com

I have numerous BA350 and BA356 enclosures available along with the power supplies, etc. I will sell separately, or try to configure to your request. Please contact me off list. Shipping from 61820, Champaign, IL area Thanks, Paul

7 years, 1 month

H7861 PSU issues

by aaron＠aaronsplace.co.uk

Hi everyone, I've been trying to figure out what is wrong with the 12V rail on my H7861 (BA11-S) power supply. It's showing about 4.2V. The 5V rail is spot on. Page 39 of the following schematics is the main part board of the PSU. http://bitsavers.org/pdf/dec/qbus/MP01233_BA11-S_schem_Mar81.pdf Going into the collector of Q3 is about 80V coming straight from T2 (I think I measured it at about 100Hz), but the emitter is putting out the 4.2V, which is the same as the base voltage and output voltage. I tried replacing this transistor because the hFE was about 80 and a good one was about 120. Unfortunately it didn't do anything. None of the capacitors look swollen and I don't see any leakage. There is a smaller board which I think goes into J4. The 12V side seems to have a 555 timer and adjusting the pot doesn't change the voltage at all. My understanding of switchmode power supplies is very poor. Does anyone have some pointers on what to check or what might be the possible cause? Hopefully I can get my PDP up and running again... Only got about 20 minutes use out of it. Thanks! Aaron.

7 years, 1 month

An interesting read

by dkelvey＠hotmail.com

Look at Dr Dobb's August 1979. There is an article on computer crime. It is interesting how times have changed. Dwight

7 years, 1 month

DEC RX03 RT11A file extractor

by cclist＠sydex.com

List: This is the first time I've run across a bunch of double-sided 8" double-density floppies in RX02 encoding. I'm assuming that this is what's known as the RX03. The system is identified on disk as RT11A. Does anyone know of a program to extract the files from images of this sort (1,025,024 bytes: 26x256 sectors/track, 2 sides, 77 tracks)? I've tried John Wilson's PUTR, but it hangs when it sees the image--I can mount the image, but then anything after that just hangs the program. I'd prefer a Linux program, but DOS/Windows would be fine. Otherwise, I'll sharpen my pencil and get coding... Thanks, --Chuck

7 years, 1 month

Which Dec Emulation is the MOST useful and Versatile?

by computerdoc＠sc.rr.com

Hi DEC Enthusiast's, If I were to have to decide on just one model DEC PDP system to run in a DEC Emulator, which one would be the most useful, versatile and has the most software available for it? I have only ever used a real PDP-8/e system way back in high school so I'm not up to par on any other model of DEC PDP system and I only know BASIC on the PDP-8/e so not much there either. I hear a lot about the PDP-11. I found out that there were 16 major PDP models at one time so I'm not too sure which one to pick. I built Oscar Vermeulen's PiDP-8/I which I'm waiting on 1 part for. Other than that project which is in a holding pattern at the moment, I have no other PDP anything running in any form. Back in the day when Bill Gates and company 1st started out, I had always wondered how they developed their very 1st software program - Altair Basic. I was pleasantly surprised one day when I saw a B/W photo of a young Bill Gates bending over the operator at what looked like a very small computer. Maybe it was just a terminal. I don't remember. I understand they did software development on a DEC PDP of some sort. Finding this out regenerated my interest in the DEC PDP line of computers. I have many projects in the works already so I decided to setup a software emulation of just one of the DEC PDP models. I have heard a lot about the PDP-11 which if the information I read is correct was 16-bits. My PiDP-8/I is 12 bits. I understand the PDP 10 was 36-bits and the PDP-15 was 18-bit. The PDP-11 is the model I hear the most about. I also have some experience on some version of a VAX when I was in the Air Force so I'm thinking of getting a VAX emulation going at some point too. So if I'm going to do this, what suggestions, pointers, experiences, etcetera do you guys have for me. I am very interested in the DEC PDP equipment though next to no experience so I have no basis to make a decision. This is a serious request so I would definitely like to hear what you all have to say. If you have read this far, thank you. Take care my friends. Kip Koon computerdoc at sc.rr.com http://www.cocopedia.com/wiki/index.php/User:Computerdoc

7 years, 1 month

DECwriter II available for pickup in Gosport, Hants, UK

by binarydinosaurs＠gmail.com

Hi folks, As the subject says. It's been stored in a garage for many years but is in pretty good condition. Free for pickup. Cheers, -- adrian/witchy Owner of Binary Dinosaurs, the UK's biggest home computer collection? www.binarydinosaurs.co.uk

7 years, 1 month

Which Dec Emulation is the MOST useful and Versatile?

by cclist＠sydex.com

On 10/30/2017 03:44 PM, Paul Koning wrote: > The timing is carefully orchestrated, including of course provision > for cable delays. I'm reminded of a unit manager at CDC that I worked with for a time. His first job at CDC as a fresh EE out of UofMinn was to measure all the loops of cable on the backplane of the then-new 6600 to which Seymour had attached tags that read "TUNE". One marvels at the fiddling that must have been involved getting the thing to run. Fun with taper pins... Cray was certainly a character. Another associate regaled us with his experience outside Seymour's lab in Chippewa Falls, sitting with a couple of others in a car on a cold dark winter night exchanging code and listings with Cray's daughter at the door. He was not about to let them inside... --Chuck

7 years, 1 month

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test-drb November 2017