test-drb March 2010

test-drb@ccmp.vtda.org

182 participants
231 discussions

by classiccmp＠philpem.me.uk

Hi guys, Quick update regarding the disc analyser... Latest news is: * The USB interface is now running properly at full speed. Write-to-buffer has gone from 84Kbytes/sec to over 180 with two small firmware tweaks. Read speed is a little under 250Kbytes/sec, which means the entire 512K buffer can be read out in a shade over two seconds. It's not going to win me any awards, but I think it's plenty fast enough. * It Has A Name! One of my friends suggested "DiscFerret" partly as a slight dig at the Catweasel. The name has stuck to the point where I've... um... registered a .com domain name for it... (hey, it only cost ?12). I'll be setting up the site as soon as I find a nice Wiki package that isn't bloated to the size of a small main-sequence star (*koff* Mediawiki). * Schematics are basically done. I need to test the power supply section, which is on the to-do list for a bit later on. Soldering down the QFN-packaged power regulator IC will be interesting. * There's an external power output for disc drives. It provides +12V at 1.5A and +5V at 1.5A. Perfect for running small 3.5in drives, and saves a mains socket. Haven't decided on a connector, but the +12 is fed directly from the input power supply, so if you connect a 15V PSU you'll see 15V on the EPS output. * Power supply can accept between 9 and 15V, though it is specified to operate with peak efficiency at approx. 12V. Input is reverse-polarity protected with a grounded-gate low-Rds(on) MOSFET. I'll probably be building up a prototype power supply board tonight or tomorrow, and giving that a good beating with a homebrew DC load. I think I've got some MJE3055s and trimpots somewhere, though whether they'll work with Vce=1.2V remains to be seen (I suspect a MOSFET might work better). But first I need to get my paws on some 0.5mm carbide drill bits. There are a couple of vias on that board that are in a really tight spot... I make no secret of the fact that it was designed to be commercially manufactured, not haphazardly assembled by some semi-skilled engineering student in a garden shed (i.e. me!) The plan for those is to drill out the holes, push in a resistor leg flush with one side, solder on one side, cut and file flush on the other side, then solder that side too. I figure that should be a tight enough fit that the wire won't be going anywhere... and if that doesn't work there's always 26SWG tinned copper wire. Cheers, -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

14 years, 5 months

cctalk Digest, Vol 79, Issue 56

by marvin＠west.net

From: Josh Dersch <derschjo at mail.msu.edu> > (As a related aside, is there *anywhere* one can get hard-sectored 5.25" > floppies these days?) People have been known to make their own 5 1/4" hard-sectored disks. I don't remember the details, but the basic idea was to take a 5 1/4" disk drive to hold the disk, make an index wheel for the holes, add a hole punch, and then just add time.

14 years, 5 months

Does a Northstar S-100 Bus Horizon Classify as a Classic

by acheel＠internode.on.net

Hi Dave, Interested to read about your Northstar S100 bus computer I have two of these withdual 51/4 disk drives sitting in my shed here in Adelaide South Australia I think I also have some manuals and software somewhere in the shed as well Are these of any value ? I also have some DEC desktop comuters and screens, disk units and tape units along with some operating software Kind regards Andy Cheel

14 years, 5 months

Probably offering TC11 controller

by hachti＠hachti.de

Hi folks, I'll most probably offer a TC11 controller for sale in the next days. The controller connects to a pdp11's Unibus and can handle up to eight TU55/TU56 tape transports (i.e. four TU56). It is configured for TU56 control levels ("integrated circuit"). Ebay would probably be the easiest way to handle a transaction with overseas buyers. Are there interested persons willing to pay nearly USD 150 for shipping? Regards, Philipp

14 years, 5 months

IBM Monochrome "Black and White" Parallel card double iimage

by billdeg＠degnanco.com

> This is certainly not a capacitor problem... > > I think this board uses 2144s as the video memory > So my first guess is to replace the RAMs. > > -tony > > ---- > > I'd be looking for a stuck address bit, or possibly a failed RAM chip > My money's on a 74xx chip (possibly a counter, buffer or multiplexer) > that's had an output fail open. > > Phil > > ----- > Along with Phil's suggestion of memory addressing issues resulting in a > double-scan of the memory, the staggering of the images suggests interlacing > might be occurring when it shouldn't be. Sometimes it is possible to tweak the > V/H-hold controls enough on monitors to end up with interlacing occurring when > it shouldn't. Can you discern whether each of the scan images contains a full > set of lines vs half the number of lines? > > I hate to ask, but what sort of monitor is this being displayed on? > IIRC the scan rate for MDA was higher than NTSC and I'm not not sure whether an > NTSC monitor would sync up or sync down to half the scan rate. > > Brent ----------------- Thanks for the feedback. I am using a standard IBM monochrome monitor. I tested the monitor with another known-working card, and I also tried another monitor. The problem is with the display card. This is one of the original black connector versions of the IBM 1904057 XM 407 display cards. It has 9114 RAMs in it, not socketed of course, so I think if I can probe each RAM chip first to ID the bad chip it'd be more efficient. I would similarly have to check the 74L chips. oy! Bill Degnan

14 years, 5 months

Data I/O29A

by mdelepeleire＠hotmail.com

Hello, I cannot find doc informing how to send ie an .HEX file from Hyper terminal to my programmer, when the programmer sends a file to the cpu the format is a sort of a start character, the address of the first byte and then a series of : HH HH HH HH HH etc where H stands for a hex symbol. Do I need to translate the Intel Hex file or how can I send an OMF-51 file? Do I have to use another communication program?? Thanks if you can help me. Marc De Lepeleire _________________________________________________________________ Hotmail: Trusted email with Microsoft?s powerful SPAM protection. https://signup.live.com/signup.aspx?id=60969

14 years, 5 months

slashdotted - home built turing machine

by rdawson16＠hotmail.com

Did you guys catch this: http://aturingmachine.com/ Cool! Randy _________________________________________________________________ The New Busy is not the old busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID27925::T:WLMTAGL:ON:…

14 years, 5 months

IBM Monochrome "Black and White" Parallel card double

by billdeg＠degnanco.com

> > If it's the original IBM5151 monitor, remember there's no horizontal > oscillator in the monitor. The Hsync (or more correctly HDrv, which is > what IBM called it) output from the MDA card goes to the base of the > horiztoal driver transistor, the collector is then transformer-coupled to > the base of the horizotnal output transistor. > > This means a 5151 will try to run at whatever freqeucny you give it, the > horizotnal output stage is likley to protest if it's way off, though. I > don;t think that if you give it an HDrv of the wrong frequency it will > ever give you a double image. > > -tony > It is a 5151. I was able to reproduce the problem on a newer monochrome monitor. bd

14 years, 5 months

HP 64000 relocatable file format / assembler

by classiccmp＠philpem.me.uk

All this talk about the HP 64000 has got me thinking... The HP 165xB Inverse Assembler Toolkit includes a DOS-based table assembler that appears to be derived from something used on the HP 64000, and it spits out what the manual calls a "HP 64000 format relocatable object file". This is what the analyser loads to run an IA. Did HP ever publish a spec for the .R (relocatable object) file, or has it ever been successfully reverse engineered? This is one of those "curiosity killed the cat" type projects; I've been wanting to use the HP LA inverse assemblers on a PC since I got my 1651B (mainly because a PC can theoretically handle a much larger symbol table). Writing an assembler / compiler for my own custom format and VM is always an option, I suppose, but I'd rather like to be able to run the HP IAs that I don't have the source code for (ISTR I've got a 68000 one somewhere). Thanks, -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

14 years, 5 months

Whatever happened to the DG software archive...

by mjkerpan＠kerpan.com

... that was announced by Bruce Ray back in December. The original posting promised details in a few weeks but AFAIK such details never can forward. Did something happen to cancel the deal at the last second or are things just taking longer than originally thought. Mike

14 years, 5 months

← Newer
1
...
4
5
6
7
8
9
10
...
24
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb March 2010