test-drb September 2015

test-drb@ccmp.vtda.org

198 participants
312 discussions

by jnc＠mercury.lcs.mit.edu

> From: drlegendre > I'm not sure what you're describing. Can you link to a pic of one of > these caps? http://www.electrical4u.com/images/glass-capacitor.jpg > From: tony duell > Incidentally, what are you using those capacitors for? I'm taking a half-filled QBUS memory card and filling it. > Why not some other type? Because on that board, they fitted _underneath_ the DIP sockets, and nothing else will fit down there! > I am pretty sure they are not polarised, you can fit them either way. > In general capacitors under 1uF are not polarised > ... > Anything over 100uF is very likely to be polarised. Thanks, help much appreciated! Noel

8 years, 6 months

Aresco Newsletters

by mikolaym＠yahoo.com

Hi all, Out of curiosity, did anybody on here subscribe to any of the newsletters published by a company called Aresco back in the late 70s and early 80s? These newsletters were VIPER (Cosmac VIP), Paper (Commodore PET), Source (Exidy Sorcerer), and Rainbow (Apple II). Aresco also published a series of books by Tom Swan titled PIPs for VIPs. I own several issues of VIPER, but I'm still looking for copies of the others. Does anybody have these newsletters in their collection? Matt

8 years, 6 months

Robotron K1840 .. (11/780 alike..)

by holm＠freibergnet.de

Hi, some people from the "Rechenwerk Halle" (http://9hal.ath.cx/usr/digital-ag/projekte/andere/museum/) ..a bunch of people that is interested in historical computing got an Robotron K1840 DEC 11/780 clone lately and they try to get it running again. (freinds of mine). Unfortunately a thing called SKR Busadapter (Massbuss adapter) and the entire console computer are missing. So far as I know is the main CPU 100% compatible to the DEC original using an UNIBUS System, PCBs are exchangeable, but the Console Computer is not. In The K1840 this is a K1620 Computer, the CPU is build from 8 Bit NMOS slices (U830) and ordinary EPROMs (https://de.wikipedia.org/wiki/U830C) using a mechanical different PCB System. The same system was used in the K1630 PDP11-alike (see below) which had an MMU (K1620 has none). The Main difference that's preventing unpatched OSes are the U834 Bus interface ICs, that must be software configured before the devices can be accessed from the QBUS-like System Bus. The U834 are containing the Bus drivers and all needed registers for interrupt and DMA and the entire address decoder logic needed for QBUS Systems which simplified the interfaces somewhat. Nevertheless of that progressive design, it was the worlds slowest PDP11.. In the K1840 ordinary TEAC FD55FV Floppies (2x) where used for the console System to boot up the system. So far so good (or bad). There are a few things that I want to know now.. I know that in the original 11/780 the Console CPU was an 11/03 with some interface to load the VAX Microcode in to the main CPU. Do you think it is possible to use an ordinary 11/23 instead? What Floppy Controller was used in the original, I know that there was a single 8" floppy drive in the 11/780 and don't think that the controller was the usual RX01 or RX02 System...? That's an article from the german magazine C't about the people which got the K1840: http://www.heise.de/newsticker/meldung/Rechnende-Schrankwand-Computermuseum… That's the K1840 on the left: http://9hal.ath.cx/usr/digital-ag/log/K1840_im_Rechenwerk.jpg and The K1630 .. PDP11 not so "clone" on the right. I don't think that the Tape drive was shipped with that machine, the bulgarian original looked different so far as I remember.. Is there someone that would help out them with missing hardware/software? Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741

8 years, 6 months

IBM 026 - Decision Data 8010 card punch on Ebay in Germany

by mattislind＠gmail.com

Not really a 026 but maybe contemporary with the 029: http://www.ebay.de/itm/Historische-EDV-Lochkartenstanzer-Card-Punch-von-197… Not mine.

8 years, 6 months

DEC handles

by jnc＠mercury.lcs.mit.edu

> From: Joseph Lang > How many do you want? How many do I need, or how many do I want? :-) I'm tempted to buy the whole bin (unless it's like a 55 gallon barrel :-), and hold onto them for other CCTalk people who need them. Maybe this will work: if you find them, point them out to the store people, and tell them I'll call? Would that be the easiest thing for you? Thanks! Noel

8 years, 6 months

ESR Meter Recommendations

by seefriek＠gmail.com

I'm going to be working on my 11/730s power supply, so I'm in the market for an ESR meter. I've seen some (older) recommendations for the AnaTek 'Blue' and various 'Dick Smith' derivatives. However, eBay is flooded with knockoff Mega328 based ESR/Transistor/SCR/etc. testers all looking like: http://www.amazon.com/DROK-Multifunction-Mega328-Transistor-Capacitor/dp/B0… Anyone had any experience with one of these devices? KJ

8 years, 6 months

Ping to Tim Shoppa

by jhfinedp3k＠compsys.to

This post is for Tim Shoppa. This have seen your replies every so often on classiccmp, so you don't seem to be totally out of touch. If you are reading this, Alan Frisbie and I would appreciate some help. Allan can be reached at the address to which I sent a copy. Jerome Fine

8 years, 6 months

PDF for RT-11 V05.07 Release Notes

by jhfinedp3k＠compsys.to

This request is for Al Kossow. However, if anyone else knows where AA-5286M-TC is located as a PDF on the internet, it would be appreciated. I have downloaded the V05.06 PDF from one of the mirrors: AA-5286L-TC_RT-11_System_Release_Notes_Aug91.pdf http://bitsavers.trailing-edge.com/pdf/dec/pdp11/rt11/v5.6_Aug91/AA-5286L-T… THANK YOU very much for making this PDF available. However, I don't see the V05.07 PDF of the RT-11 Release Notes anywhere. If there is a copy, could you please provide the link? I presumed that if it existed, that PDF file would have been at: AA-5286M-TC_RT-11_System_Release_Notes_Aug98.pdf http://bitsavers.trailing-edge.com/pdf/dec/pdp11/rt11/v5.7_Aug98/AA-5286L-T… but that sub-directory does not exist. As I have mentioned in a previous post, the RT-11 DOC set manuals for V05.06 and V05.07 are IDENTICAL except for: AA-5286L-TC RT-11 Release Notes for V05.06 of RT-11 which was dated August 1991 and AA-5286M-TC RT-11 Release Notes for V05.07 of RT-11 which was dated October 1998. Does anyone else know if the V05.07 RT-11 Release Notes manual is available as a PDF? If so, could it be added to the bitsavers mirrors? Jerome Fine

8 years, 6 months

ESR Meter Recommendations

by jnc＠mercury.lcs.mit.edu

From: Eugene (W2HX) > to model this using ideal components, we show a resistor in parallel to > the capacitor ... This modeled parallel resistor represents the leakage > current. > ... > because it is not ideal, some power is dissipated. This dissipated > power is represented by a series resistance. Because an idealized > circuit with a cap and a resistor in series will not pass DC current, > this circuit must be tested at AC. So I'm slightly confused; you talk about the model being a parallel resistor (which I get), but then switch to a series resistor. Why the switch? Noel

8 years, 6 months

A new Lisp-based OS that hearkens back to the old days of comprehensible computers

by lproven＠gmail.com

A little offtopic but I hope of some interest. I rather miss the days of small, simple, 8-bit computers which a single non-specialist could really get inside and understand. The latest OS I've seen which addresses this longing is Interim. http://interim.mntmn.com/ This is most of the introduction from the explanatory paper: ? Computers, networks and the software running them today are shrouded in mysteries and corporate secrecy. As miniaturization progresses in the name of mobility and energy-efficiency, an increasing amount of complex functionality is crammed into ever smaller System-on-Chip dies. The so-called "Home computers" of the 1980s contained comparably larger and simpler circuit boards with blocky, easily discernible DIP (Dual in-line package) components and circuits that could be visually understood by the human eye. The central processing unit (CPU) was easily identified by its size and exposed placement. The separate memory chips were neatly arranged like terraced houses. The computers worked in pedestrian single-digit-Mhz speeds and memory was measured in kilobytes. They shipped with handbooks that taught a novice reader how to program the machine, and a circuit diagram of the whole machine ? useful for repairs ? was easily available. In the 1980s home computer era, operating systems where typically stored in read-only memory (ROM) chips. As in modern proprietary operating systems, the source code was not directly available, but this was not strictly necessary, as they were written in assembly language and not "compiled" from a higher level language. Commented "dis-assemblies", machine code listings, were available in printed book form [Schineis1984] for popular computers like the Commodore 64 and its "KERNAL" OS and BASIC language interpreter. Today, we have Linux, probably the most successful open source Unix-like operating system and the BSD family of OSes, but these systems and most of the platforms they run on (PCs, ARM-based telephones) are so complex and contain so many obscure components that no single book can describe their operating principles in full detail, and trying to understand and master them is a task that takes many years of study. With "Interim", I try to describe a computer and operating system that takes advantage of modern-day hardware technology while ideally being fully comprehensible in a couple of days. My strategy is to use minimalism and generic, reusable patterns wherever possible while learning from historical, ultimately unsuccessful but valuable attempts like Lisp machines or the operating system Plan 9 from Bell Labs [Pike]. The Interim system is supposed to be a pointer in the right direction, not a perfect blueprint, and a documentation of my own experimental attempts. Others may build upon these ideas. ? (Yes, it's Lisp-y.) The previous OS with this view being TempleOS: http://www.templeos.org/ This is a nice explanatory quote: ? The main reasons TempleOS is simple and beautiful are because it's ring-0-only and identity-mapped. Linux wants to be a secure, multi-user mainframe. That's the vision for Linux. That's why it has file permissions. The vision for TempleOS is a modern, 64-bit Commodore 64. The C64 was a home computer mostly used for games. It trained my generation how to program. It was simple, open and hackable. It was not networked. The games were not multimedia works of art, but generated programmatically with innocent, programmer (non-artist) quality graphics. It was simple and unsecure. If you don't have malware and you don't have bugs, protection just slows things down and makes the code complicated. ? Source: http://www.templeos.org/Wb/Home/Wb2/TempleOS.html -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) ? +420 702 829 053 (?R)

8 years, 6 months

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test-drb September 2015