test-drb

test-drb@ccmp.vtda.org

101090 discussions

by boris＠summitclinic.com

TAhanks for that link which fits with my measurements (nowhere as detailed) of ones actual ability to do things with "modern" hardware. In the 1980's I was used to being able to measure events with 0.2 microsecond precision using a PDP-11 and my expectation was that the accuracy was only going to improve as processors got faster. I ported a program I wrote on the PDP-11 to a Commodore 64 in 1988 and was using it to measure finger tapping with a switch array to 1 msec accuracy. This was done through the simple expedient of speeding up the sample rate for the keyboard to 1 KHz and the adding in my 4 external switches as "keys". Used a 512 K Mac to get the serial data and display results. To do the same now would require custom hardware to do the timing and a USB link to a "modern" CPU or implimentation on a microprocessor When I attempted to get this same type of timing accuracy from a PC, found out that it was no longer easy to get access to interrupts as easily as before and keyboard latency was longer as now keystrokes were detected by an on board microprocessor and sent out as a series of packets for each keystroke. In DOS and W95 where one could still easily get at interrupts, then a serial port could be used to do msec timing. Once XP and beyond arrived, then the best temporal precision one can expect from a 3 GHz machine is 15 msec. I suspect the same holds for Macs and haven't tried running real time Linux as I either pull out my trusty C64 from time to time and use it for precision timing (unfortunately have only one copy of the code on casette tape so when that goes can't do this anymore) or I use various microprocessors to do the job. Have a nice microsecond precision timer that I wrote for a Propeller chip and feel much more comfortable programming for it than the latest windoze bloatware system. The Propeller has the same amount of RAM as the PDP-11's I started on, runs 20x faster/core and is fun to program. The microsecond timer is attached to a geiger counter to generate random bytes for OTP encryption. Boris Gimbarzevsky >On 29 March 2018 at 19:53, Paul Koning via >cctalk <cctalk at classiccmp.org> wrote: > > > > It would be fun to do a "generalized Moore's > Law" chart, showing not just transistor count > growth (Moore's subject) but also the many > other scaling changes of computing: disk > capacity, recording density, disk IOPS, disk > bandwidth, ditto those for tape, CPU MIPS, > memory size, memory bandwidth, network bandwidth... > >This is the most telling I've seen in a long time... > >https://danluu.com/input-lag/ > >-- >Liam Proven ? Profile: https://about.me/liamproven >Email: lproven at cix.co.uk ? Google Mail/Hangouts/Plus: lproven at gmaill.com >Twitter/Facebook/Flickr: lproven ? Skype/LinkedIn: liamproven >UK: +44 7939-087884 ? ??R (+ WhatsApp/Telegram/Signal): +420 7002 829 053

8 years, 4 months

Last call for free old manuals

by sales＠elecplus.com

I have many cases of SAMS facts schematics and other repair manuals for everything from stereos, tube TVs, ham radios, turntables, etc. Most apply to equip from the 60s and 70s or maybe a little earlier. Free to a good home or they go in the recycle bucket tomorrow. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com AOL IM elcpls --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

8 years, 4 months

8085 Dissasembly?

by jnc＠mercury.lcs.mit.edu

> From: Charles Anthony > discovered that changing the executable would change the behavior -- a > heisenbug. Ooh, love that neologism. Noel

8 years, 4 months

TRS-80 bits

by wrm＠dW.co.za

Hi all I have a TRS-80 Model 2000 B/W Graphics board and a TRS-80 Card Cage kit (upgrade model 12 to model 16B) Are either of these worth shipping from the antipodes to anyone? W

8 years, 4 months

FYI: IBM System/34 available in Boston, MA

by cclist＠sydex.com

Just noticed this post on the Vintage Computer forum. I don't know a thing about it: http://www.vcfed.org/forum/showthread.php?63253-IBM-System-34-5340 --Chuck

8 years, 4 months

Absolute OpenBSD book

by mark＠wickensonline.co.uk

This is available for the cost of postage. https://photos.app.goo.gl/OpVKxtbXqKp2VPl52 Mark.

8 years, 4 months

Help on a 1998 Award BIOS chip

by curiousmarc3＠gmail.com

After battling for days with a Dolch 65 that developed the two-tone beep-of-death on boot, I finally found that it's just my BIOS ROM that has gone bad. The BIOS happens to be an Award BIOS, says "Award 1998 PCI/PNP 686" on the chip. It's a square chip with pins on the side. Photo here: https://drive.google.com/open?id=1OtZ1AU0Hac8RlzTgbgCY4z_qcMlGWXu1 So I thought I might just ask. Anyone has a dead Dolch 65 motherboard from which I could steal a BIOS chip. The board is actually an Advantech CI6BM-B1 industrial single board computer. Or alternately, can someone identify what kind of ROM or EEPROM that likely is, and provide advice on how to read the data from a good chip (I have another good chip in another Dolch, that's how I found out what my problem was), and program a similar chip. Marc

8 years, 4 months

8085 Dissasembly?

by w2hx＠w2hx.com

Hi friends. I have a 1990's vintage commercial radio system that uses an 80C85A CPU. I am looking to hopefully modify the firmware to make some small changes in its behavior. The firmware is contained in two EPROMS. Can anyone recommend a decent disassembler to use with this? Preferably something that ran in windows 10 or windows 7? A dos box would be fine too. Also, I looked through the dumped contents of the EPROM. In the past I have seen EPROM ascii dumps where most is unintelligible to the naked eye but typically text messages give to the users during interaction with the program are human readable. In this case, the ASCII dump shows only other HEX data. I believe I read that there is a HEX format and that I might need to convert from HEX to BIN before disassembling. Of course, an ideal tool would do both if anyone knows such a thing. I am not familiar with 8085 stuff but any insight would be appreciated. Lastly, I wonder if there might be some kind of checksum check to prevent tampering. Is there a common way this is handled in 8085 world? Or is it entirely programmer dependent? Thanks for your time Eugene W2HX?

8 years, 4 months

Kaypro II keyboard fault / keyswitches wanted

by jules.richardson99＠gmail.com

Hey all, I snagged a Kaypro II a short while ago which I finally got around to looking at. After some minor TLC to the drives, it's booting. However, the keyboard appears unresponsive. Pressing keys (with the exception of caps-lock, the two shifts, and ctrl) results in a buzz/click >from within the keyboard - if I'm interpreting the schematics right, the click is actually driven by the system in response to a keypress, which suggests that my keyswitches are OK (I believe these use a foam disc approach, which are prone to deterioration) and that keyboard data is being received OK (at least on some low level). Any suggestions for possible things to investigate? It doesn't feel like a memory fault, given that it's using 64kx1 ICs and booting as far as a prompt, but I suppose it's possible. On the back of this, I'm in need of three keyswitches, if anyone happens to have a parts machine and would be willing to sell any. A student of the machine's previous owner dropped the keyboard years ago and broke three of the keys off. I have the keycaps, but the switch stems are broken and it would probably be easier to replace the entire stem portions rather than attempting to glue things back together. cheers Jules

8 years, 4 months

Big old Telex terminal

by sales＠elecplus.com

https://www.recycledgoods.com/telex-277d-terminal-with-95146r011-keyboard-ib m-model-2-compatible/ Not affiliated with seller, etc. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com AOL IM elcpls --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

8 years, 4 months

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