test-drb

test-drb@ccmp.vtda.org

101090 discussions

by kylevowen＠gmail.com

Just thought I'd share with you all one of my pet projects for the past few years. I have written an HP-35 and HP-45 simulator for the PDP-8, which uses the original microcode from these calculators. Thus, it is just as accurate as the original calculators, I would believe. Not really sure why I decided to do this, but I suppose I enjoy both HP calculators and PDP-8 programming. I guess it's nice to have a scientific calculator at one's disposal too while sitting in front of a PDP-8, too. It also shows that something like this could've existed back in the early 1970s if one were so inclined to do it. Perhaps it's also a bit of homage to the Expensive Desk Calculator for the TX-0 and PDP-1. Anyways, you can grab the code from here: https://github.com/drovak/hpcalcpdp8 The HP-45 support is new as of the past couple of days; I went ahead and through in a help function to explain the keys. Toggle between 4XXX and 0XXX on the switch register to toggle between HP-45 and HP-35 modes, respectively. Feel free to give feedback; I've tested it fairly extensively in SimH with no major issues other than no error indication on the HP-35. I have a debug mode which prints each register every instruction cycle, but I haven't used it too much in recent times; I went ahead and IFDEF'ed it as it also reads from the switch register. OS/8 support will come soon, as that shouldn't be challenging. You need 8k to run this, though I also uploaded my original hp35pdp8.pal code which runs in 4k. It lacks the help function (and obviously the HP-45 simulator), but otherwise, works pretty much the same. Big thanks to Eric Smith for his 'nonpareil' work which inspired much of the simulator. Kyle

9 years, 5 months

changing Subject header in thread [was Re: Ill-considered complaints [was: RE: early networking (was Re: G4 cube (was Re: 68K Macs with MacOS 7.5 still in production use...))]]

by spacewar＠gmail.com

Rich Alderson wrote: > Actually, Mr. Cook, the standard for the last 35 years or so has been to > change the subject line, with the old subject in SQUARE BRACKETS with the > characters "was: " prepended. Any decent newsreader or threading mail > reader knows how to deal with that, and threading is unbroken. What was > broken in the messages about which you complain is the substitution of > parentheses () for brackets []. I had no idea that there was a standard. Is it in an RFC or something? I've commonly seen either parenthesis or square brackets used, and I've normally used parenthesis myself, but if there's a documented standard, I'll consider switching.

9 years, 5 months

Internet of Things (was Re: Linux at 25)

by spacewar＠gmail.com

Chuck Guzis wrote: > I was a bit surprised to > find that my home thermostat was running BusyBox. Cameron Kaiser wrote: > s/surprised/alarmed/ > Remember, it's going to be the Internet of Pwned Things before too long. Unfortunately most people elide the first two letters of the initialism, leaving only "IoT". It is actually the "Insecure Dangerous Internet of Things".

9 years, 5 months

PDP-8 Code Optimization (was Re: HP-35/45 Simulator for PDP-8)

by kylevowen＠gmail.com

On Tue, Sep 13, 2016 at 3:38 PM, Doug Ingraham <dpi at dustyoldcomputers.com> wrote: > > Thanks for an interesting bit of optimization! Need some more optimization fun? :) Vince and I were working on some code to add two signed 12 bit numbers and detect overflow, returning MAX_INT or MIN_INT in AC in the case of overflow, or the sum in AC otherwise. Here's what Vince came up with so far: CHKOVF, 0 TAD OVFA /GET A TAD OVFB /ADD B DCA OVFSUM /SAVE IT TAD OVFA /A XOR B AND OVFB CMA IAC TAD OVFA TAD OVFB SPA CLA /IF SIGNS DIFFER... JMP NOPROB /WE'RE DONE TAD OVFA /MIGHT BE OVERFLOW, A XOR SUM AND OVFSUM CMA IAC TAD OVFA TAD OVFSUM SMA /DID WE OVERFLOW (DIFFERENT SIGNS)? JMP NOPROB /NO, NO PROBLEM CLA CLL CMA RAR /YES, AC=3777 (MAX INT) DCA OVFSUM /SAVE IT TAD OVFA /GET THE SIGN OF CORRECT RESULT SPA CLA /SHOULD IT BE NEGATIVE? ISZ OVFSUM /YES, 3777 -> 4000 (MIN INT) NOPROB, CLA /GET CORRECTED SUM TAD OVFSUM JMP I CHKOVF /OUTTA HERE OVFA, 0 OVFB, 0 OVFSUM, 0 This tests the signs of both numbers; if they differ, there's no chance of overflow. If they're the same, it checks the signs of the augend with the sum; if they differ, an overflow occurred, and MAX_INT or MIN_INT will be returned depending on the sign of the augend. We tried clever tricks previously, using SNL/SZL and SMA/SPA after shifting the sign of the augend into the link and keeping the addend in the AC, but found these to be longer. Kyle

9 years, 5 months

G4 cube (was Re: 68K Macs with MacOS 7.5 still in production use...)

by rlloken＠telus.net

On Tue, 13 Sep 2016, Liam Proven wrote: > Whereas my Mac mini has 3rd party RAM and both an SSD and an HD > (upgrades from a Toshiba desktop-replacement notebook that the Mac > replaced) on a 3rd party bracket, and I'm using a Dell 5-button mouse > and an Apple Extended keyboard from '97 or so, on a 3rd-party ADB-USB > adaptor. And a pair of mismatched 2nd hand 23" LCDs. ... > And with the original '80s keyboard, it _feels_ (and sounds) like a > proper (i.e. '80s) Mac when I'm typing on it. :-) My Mac Mini has been treated to new modern keyboard purchased at rediculous expense upon the recommendation of my long time friend G.L.Nerenberg II. And it says underneath "WASD Model: V2 Type: Cherry MX Green". It is gloriously noisy! I have an aluminum Apple keyboard in the box this keyboard came out of, those Apple chicklet keyboard are just plain horrible. -- Richard Loken VE6BSV, Systems Programmer - VMS : "...underneath those Athabasca University : tuques we wear, our Athabasca, Alberta Canada : heads are naked!" ** rlloken at telus.net ** : - Arthur Black

9 years, 5 months

bitsavers FP11-B schem: M8115-0-01 sheets 1 and 2 missing?

by fritzm＠fritzm.org

Hi all, I?m working on debugging an FP11-B floating point option in a PDP-11/45. I?ve just discovered that in the engineering drawings for this on bitsavers, sheets 1 and 2 of the FRL board prints are missing :-( Does anybody have a complete set of FP11-B drawings? I can work around the missing sheets if I have to because sheet 1 is just the IC layout sheet and sheet 2 is probably quite similar to sheet 3, but it sure would be convenient to have the whole set? cheers, ?-FritzM.

9 years, 5 months

Telnet was Re: G4 cube (was Re: 68K Macs with MacOS 7.5 still in production use...)

by cliendo＠gmail.com

Agree. It's quite easy to telnet to a port to see if you get a response. Do it a lot. > Are ifconfig, netstat, traceroute, et al really insecure? (Maybe a case > could be made for traceroute) These types of changes to the core of > userland are epic dumb IMHO. Telnet is very useful for debugging, and > certainly dropping telnetd is a good thing - which everyone has done.

9 years, 5 months

G4 cube (was Re: 68K Macs with MacOS 7.5 still in production use...)

by glen.slick＠gmail.com

On Sep 13, 2016 9:16 AM, "Al Kossow" <aek at bitsavers.org> wrote: > > I've been working on archiving documentation and firmware from microprocessor > based CRT terminals for a couple of months, since I realized they are disappearing > the same way CRT monitors have. Did you ever get any Motorola EXORterm docs that were mentioned here? http://www.vcfed.org/forum/showthread.php?44638-Motorola-EXORciser/page4

9 years, 5 months

Logic Analyser Advice

by mark＠markesystems.com

> I finally managed to pick up a logic analyser for a price I could justify. > It is a HP1630G and it comes with a number of pods. However the pods do > not > seem to have the actual wires/probes. Is there a separate part number for > these that I should look for. There seem to be quite a few items like > this: > http://www.ebay.co.uk/itm/291753390848, are these likely to be suitable > alternatives? Sign seen on an HP logic analyzer at a local swap meet: HP 1630G Logic Analyzer: $10 Complete set of probes: $500 ~~ Mark Moulding

9 years, 5 months

Recovering 4mm tar tapes

by dj.taylor4＠comcast.net

I have a pair of 4mm DDS tapes from 1999 that I would like to recover. I was able to read one with tar on a Debian (jessie) Linux system, but the second gives an error. The tape that I could read is a Sony with DDS markings and 4 bars next to the DDS logo. It was written on an SGI computer. I was able to read this with a simple tar -xvf /dev/st0 command. The second tape is a 3M brand with DDS markings and 4 bars next to the DDS logo. It also has 'Media Recognition System' and DD-90 written on it. Here is the dialog and error: root at T5400deb:/home/taylor/4mm_tar_1998# lsscsi [0:0:4:0] disk codesrc SCSI2SD 4.2 /dev/sdc [0:0:5:0] disk codesrc SCSI2SD 4.2 /dev/sdd [0:0:6:0] tape ARCHIVE 4326XX 27871-XXX 0324 /dev/st0 [3:0:0:0] disk ATA WDC WD800JD-75MS 1E04 /dev/sda [3:0:1:0] cd/dvd PLDS DVD+-RW DH-16A6S YD11 /dev/sr0 [4:0:0:0] disk ATA ST500DM002-1BD14 KC45 /dev/sdb root at T5400deb:/home/taylor/4mm_tar_1998# mt -f /dev/st0 status drive type = 114 drive status = 318767616 sense key error = 0 residue count = 0 file number = 0 block number = 0 root at T5400deb:/home/taylor/4mm_tar_1998# tar -xvf /dev/st0 tar: /dev/st0: Cannot read: Input/output error tar: At beginning of tape, quitting now tar: Error is not recoverable: exiting now The tape drive is a Seagate CTD8000R-S with COMPAQ markings. There are 5 jumpers to configure the drive and one is for MRS which the jumper config page I have says it is enabled (Default), however the pins are missing for that option. What does that mean? (None of the config jumpers were installed for the tape that I could read) Is the 2nd tape just bad and can't be read? Or do I need a slightly different tape drive? Doug

9 years, 5 months

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test-drb