cctalk March 2026

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66 participants
35 discussions

by Chris Zach

So back in the 1990's the dream server for me was an Everex system called the Step/MP. Cube shaped, EISA bus, could take multiple 386/33 CPU blades and ran SCO. But all I had was memories as there was very little info on the Net. Today I was going through a closet I haven't been able to access for 20 years and in the Computerworld 1992 25'th anniversary issue I found it: A 2 page monster ad about the Step/MP. $13k, could have six 486/33 CPUs, EISA/ISA bus, 64mb of memory stock with support for 4mb SIMMs. So it did exist.... Question is did any of them make it out there? SCO was the obvious OS, but given that it was a SMP system I wonder if there was an NT 4.0 HAL out there like there was for the NCR 3550/4300 series of multiprocessor systems. Anyone have one? Seen one in the wild? I am curious. Everex/STEP was always the best quality system for a server, right alongside Compaq. Sad they went out of business. Chris

1 month, 1 week

Looking for Codex modem manuals/info

by Richard Cini

All – I’m working on a simulation project where I’m using two Codex 2121 LDSU (local data service unit) modems to simulate a leased line setup to a DECSYSTEM-2020. These modems use 2-pair cabling (TX+,TX-/RX+.RX-) and DCE DB25 connections. I believe each modem is working in loopback mode, but I can’t get it to work over the 2-pair interface between the modems (i.e., a loop back plug on one modem and terminal on the other). The only manual I’ve been able to locate is the sales brochure, not any kind of user manual. Anyway, have the interface cross-connected (i.e., TX to RX) but there are no polarity markings so I just used each pair in the same color order. Has anyone used this kind of modem before, have a manual, or know how to connect them? Thanks! Rich -- Rich Cini http://cini.classiccmp.org https://github.com/RichCini

1 month, 1 week

Re: Your subscription for cctalk mailing list has been disabled

by Alessandro Mazzini

Test ( sorry guys for cluttering , but I'm puzzled since I'm using Hotmail so... should not have this kind of issues ) -----Original Message----- From: cctalk-bounces(a)classiccmp.org <cctalk-bounces(a)classiccmp.org> Sent: Monday, March 2, 2026 7:03 AM To: mazzini_alessandro(a)hotmail.com Subject: Your subscription for cctalk mailing list has been disabled Your subscription has been disabled on the cctalk(a)classiccmp.org mailing list because it has received a number of bounces indicating that there may be a problem delivering messages to mazzini_alessandro(a)hotmail.com. You may want to check with your mail administrator for more help. If you have any questions or problems, you can contact the mailing list owner at cctalk-owner(a)classiccmp.org

1 month, 1 week

Re: Operating system, on punch cards?

by bluewater emailtoilet.com

Punchcards? You want punchcards? I got punchcards. Not exactly what I think you are looking for but a large sample. Please check out www.punchcardarchive.com Check the Stats page for a quick summary. Beware the Album page. It takes a while to load. After all, it has to display 25532 cards. Not a full program but doing a search on CCROS in the Title field will show a few cards that represent a few bits of a read only S/360 program. Donald

1 month, 1 week

Identifying This Component from VT100 Monitor Board

by Robert Jarratt

I asked this before a few years ago but didn't come to a firm conclusion. The two parts are shown in this picture: https://rjarratt.wordpress.com/wp-content/uploads/2023/12/img_20231221_1123… They are from a VT100 Monitor board. There is no schematic for my version of the board, but a related schematic is on p58 of this schematic: https://bitsavers.org/pdf/dec/terminal/vt100/MP00633_VT100_Schematic_Feb82.…. They are labelled Q414 and CR406, but the Feb 82 revision uses a different board and those two parts are in TO-220 packages rather than TO-3 as here.. I have removed both of them and tested them with a DMM. Neither of them measure as two diodes, they do not measure open circuit in any direction, so either they are both faulty or they are not transistors (unlikely). I have found a spec for a 2SB411 at https://alltransistors.com/transistor.php?transistor=10279. This seems to be a germanium transistor. When I last asked about this I had a conversation with Tony Duell, who was very sceptical that these could be germanium transistors, so naturally I am very doubtful that they are 2SB411 transistors. However, in the schematic Q414 is shown as NPN, the 2SB411 is PNP and this seems to match the way the part is connected on my board (Collector to HORIZ GND). I am working on a reverse engineered schematic. Can anyone tell me what these components are so I can find a datasheet for them? Better still a suggested replacement would be really helpful, especially if they are 2SB411s because they seem to be hard to find. Thanks Rob

1 month, 1 week

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cctalk March 2026