September 2025 - cctalk - classiccmp.org

by Martin Eberhard

I just love the PDP11's assembly language. I needed a super-tight subroutine to print a 16-bit value as 6 octal digits. This is as tight as I could make it, 16 words (including writing to the serial port, which takes 5 words). Can you beat it? ;*** Subroutine ************************* ;Print a 16-bit value as 6 octal digits ;Calling Sequence: ; jsr PC,PROCT6 ;On Entry: ; R2 = value to print ;Trashes R1,R2 ;**************************************** PROCT6: mov #100030,R1 ;Digit loop ends when '1' lands in C ;..'30' makes it ASCII sec ;All done when this is in C again ;Extract a digit and convert it to ASCII. Check for done. 1$: rol R2 ;Shift digit out of R2 & into R1 beq 3$ ;Return when done rol r1 ;Build next octal digit bcc 1$ ;Done when c = shift pattern bit ;Write digit to the serial port 2$: tstb @#CTXSTA ;Wait for transmitter (clears C) bpl 2$ movb R1,@#CTXDAT ;Transmit now ;Next digit mov #020006,R1 ;Digit ends when "2" lands in C. ;Printing ends when "sec" bit ;..leaves R2. '6' makes ASCII br 1$ 3$: rts PC Martin E.

7 months, 2 weeks

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Ohio scientific boot discs

by George Rachor

Looking for both 8 inch and 5.25 inch boot media. Sent from my iPhone george(a)rachors.com

7 months, 2 weeks

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Huntsville Microsystem HMI-200 emulators

by Tony Jones

Crazy long shot. I just picked up a HMI-200-64180 for $75 shipped. Curious if anyone has the manual and software for it? There is some very limited info on bit savers but nothing for the 64180. I'd also possibly be interested in picking up the 6809 version if anyone has one they no longer need and the price is fair. https://web.archive.org/web/19980206071507/http://www.hmi.com/200.html Thanks

7 months, 2 weeks

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Large language model (LLM) Web Scrapers

by Bill Degnan

For those of you who run vintage computing-related info sites, have you noticed all of the LLM scraper activity? AI services are using the LLM scrapers to populate their knowledge bases. At any given moment 5-10 of them are active on vintagecomputer.net. It’s funny, when I ask an AI about something vintage computing-related, something obscure, I can trick into giving me an answer from my own site. I have actually had to modify the site code to manage the traffic, to improve efficiency. But they’re not going after just my site, these scrapers are absorbing copies of the entire WWW. I wonder how long the WWW will remain open, it would be a bummer if I found copies of my site elsewhere. Bill

7 months, 2 weeks

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Need a Connectix quick cam?

by Van Snyder

I have a Connectix quick cam. The on ly label says FCC ID LKD1. The connector is a mini-DIN that looks like a PS-2 mouse or keyboard plug. Do you need it?

7 months, 2 weeks

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Re: [List] Re: Fun with PDP11 Assembly Language

by donald donaldwhittemore.com

You want blinky lights? Try this. 😊 https://www.chilton-computing.org.uk/ca/jpgs/195_engineers_console.jpg

7 months, 2 weeks

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Re: CTOS Ethernet EDL software

by Alexei Iliasov

The driver package (B25-PDL_CTOS_Ethernet_Packet_Driver_3.7.0) also has drivers for ACCTON 1660 and 3COM 3C509 - you need to uncomment them in JCL file. I have the Accton card installed and detected in dos (and confirmed IRQ and base address) on SG3000 platform but activating the driver always crashes CTOS to core dump. The only suspect bit “Shared memory” which appears to be boot room address and this is not installed on my card (socket missing). Wonder if anyone had success with the driver?

7 months, 2 weeks

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Magellan Roadmate X11-16302

by Van Snyder

Free to good home: I re-found a Magellan Roadmate X11-16302 GPS map in my junk heap. It appears to have a dead battery, at least it appeared not to charge on USB. I don't have the AC power cube or the car's cigar-lighter power adapter. Send a PDF for a shipping label from Van Snyder 2229 Shields Street La Crescenta, CA 91214 Local pick up OK too.

7 months, 3 weeks

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Repairing an Olivetti M24 PSU

by Robert Jarratt

My Olivetti M24 was humming away nicely until I switched it off. It then failed to power on again. The PSU is not outputting any voltages on any of its outputs. The technical manual is here https://bitsavers.org/pdf/olivetti/m21_m24/Olivetti_M21_M24_Theory_of_Opera…. The PSU is described from p188 with an outline schematic on p194. The full schematic is on p274. A schematic useful to anyone with the actual board in front of them has been created in the following forum post https://forum.vcfed.org/index.php?t...ower-supply-replacement.1237316/#post…, the schematic is this one: https://forum.vcfed.org/index.php?attachments/m24_psu_schematic-jpg.1252584/. I have done some verification with the scope but I have reached a point where I am not sure what signals I should expect. I have attached a dummy load on the +12V, +5V and +15V outputs to meet the specs for minimum current. I see a 20KHz square wave on the inputs to the output transformer T438 (pins 1 and 2). The manual says that the diodes on the output rectify a half wave. I assume these are the ones labelled D134 and D136. The following image shows the signal on the two diodes marked D134 on the schematic for the 12V output, measured from their anodes to 0V output. https://rjarratt.wordpress.com/wp-content/uploads/2025/08/diodes-on-12v-out… For the other two diodes, labelled D136 for the 5V output I get this: https://rjarratt.wordpress.com/wp-content/uploads/2025/08/diodes-on-5v-outp… Do these look correct? The peaks seem to be too low to even begin to produce the required output voltage. Thanks Rob

7 months, 3 weeks

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VCFMW

by Paul Anderson

I' plan on arriving there between 1 and 2 Friday afternoon. If there is anything else you want me to bring please email me off list today. If you have any US/ foreign coins/currency I'm interested in trading or buying them. Thanks, Paul

7 months, 3 weeks

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cctalk September 2025