test-drb March 2010

test-drb@ccmp.vtda.org

182 participants
231 discussions

by pete＠dunnington.plus.com

On 22/03/2010 19:18, Alex Taylor wrote: > The idea was that reformatting a 1.44MB HD disk in a DD drive will > leave traces of the original formatting behind (as they're always > preformatted for DOS/Windows), causing the unreliability. Using a bulk > eraser is meant to eliminate this problem, as it will turn them into > completely blank disks that can be formatted in a DD drive more > reliably. That won't really matter. When you format a disk you write bit patterns all over it: in the headers, in the data sectors, and even in much of the gaps between them (sync bytes and clock patterns used as markers). Thus there's something there even when you write the first real data, and of course it never lines up exactly, bit for bit. Therefore you still have the problem of interference from the previous "data" even if it's just the dummy data used to fill a "blank" sector, and the sync bytes and markers in the preamble to it. -- Pete Peter Turnbull Network Manager University of York

14 years, 4 months

cctalk Digest, Vol 79, Issue 44

by alhartman＠yahoo.com

I don't know what the market is like in Europe, but I can still buy new media in 5.25" and 3.5" format easily here in the U.S. Google brings up many places here. If there are no such outlets in the UK, maybe you can get a bulk order together with some local folks to save on the shipping costs? Al From: Liam Proven <lproven at gmail.com> Subject: Reusing old floppy *drives* Noting the discussion on old media, a slightly different question. Please excuse my profound ignorance on matters electronic! I have read, somewhere, that it is possible to connect HD floppy drives to elderly kit that is only expecting DD drives, and use them for just DD operation. More specifically, I'd like to resurrect my ancient Sinclair Spectrum with its MGT DISCiPLE disk interface. Way back in the 1980s, I used 5?" media, as they were still cheaper. However, now, I daresay I won't find any new 5?" media and even 3?" DD media are getting tricky. So what I was considering doing was connecting a pair of old PC floppy drives - 3?" HD (1.4MB) floppies - and quite possibly using 1.4MB media, but only formatting them to 720K and using them as 720K. IIRC, the drives permit this. The track widths are the same - both are 80t drives - it's just that DD used 9 sectors per track and HD 18. Is this likely to work? I realise I'll need to find drives with a unit selection jumper on them, so I can set one as 0 and the other as 1; no twists in the cables this far back, & I'm guessing that a twisted cable wouldn't work with a controller that wasn't expecting it...? -- Liam Proven ? Profile: http://www.linkedin.com/in/liamproven Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419 AOL/AIM/iChat/Yahoo/Skype: liamproven ? LiveJournal/Twitter: lproven MSN: lproven at hotmail.com ? ICQ: 73187508

14 years, 4 months

Tektronix manuals available

by auringer＠tds.net

Hello, I have the following Tek Instruction Manuals sitting here. I would like to free up the space they are consuming. If someone wants to make it worth my while to spend the time shipping them out, I will entertain offers. Otherwise, I will dump them in the recycling. Preference will go to the fewest number of boxes I have to deal with and, of course, compensation offered. I will accept offers until Sunday (28th) evening. I will ship or recycle Monday. Shipping from 53714. Jon -- 7904 Oscilloscope operators 7904 Oscilloscope Service 7A13 Differential Comparator 7A19 Amplifier 7A26 Dual Trace Amplifier 7B92A Dual Time Base 7B80 Time Base 7B85 Delaying Time Base 7M11 50-Ohm Delay Line S-6 Sampling Head S-52 Pulse Generator Head S-53 Trigger Recognizer Head C-5C Camera 2215 Oscilloscope Service P6056/P6057 Probe P6131 Passive Probe P6460 Data Acquisition Probe K212 Portable Instrument Cart 1240 Workbook I also have "data sheets" for the following items: P6063B Passive Probe 200C Scope-Mobile Cart

14 years, 4 months

mewel

by mcl198＠frontiernet.net

Hello, Does anybody have the source code and libarays for the old MEWEL windows interface? I have been looking for this so the source code for a Juki Pick and Place machine can be updated. If there is a fee for this, just let me know. Thanks, Patrick McLeod McLeod Instruments, Ltd. 928-535-6369

14 years, 4 months

Async logic

by julianskidmore＠yahoo.com

Alexey Toptygin wrote: > What's wrong with pulse or async logic designs? I personally find them > fascinating, but I've never gotten to play with an implementation of > one... Are there problems with designing like this that made people switch > to sync designs? Anyone know of any good books on non-synchronous logic > design? Probably the best resources are the Amulet resources from Manchester University. http://intranet.cs.man.ac.uk/apt/async/ In the late 90s they experimented with Asynchronous ARM processors. The difficulty with asynchronous design is that it's far more prone to race hazards than synchronous design. Also, they found that even the simple handshaking protocol they used limits performance. Nevertheless, they do have some advantages, for example their EMF emmissions tend to be evenly spread across a broad spectrum. Incidently, modern synchronous design is far less synchronous than it used to be; high clock rates mean that CPUs are subdivided into differently clocked domains to avoid clock skew. -cheers from julz @p

14 years, 4 months

eBay Oz : Collection of DEC Unibus modules including custom wire-wrap

by unibus＠gmail.com

> > Message: 6 > Date: Tue, 16 Mar 2010 20:12:10 +1100 > From: Nigel Williams <nigel.d.williams at gmail.com> > Subject: eBay Oz : Collection of DEC Unibus modules including custom > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk at classiccmp.org> > All sorts of interesting items: TU-60, CM-11, M792 etc > > http://shop.ebay.com.au/pdp11.caps11/m.html?_nkw=&_armrs=1 > > not connected with seller, however I did purchase fanfold paper-tape from > this eBayer. > I'm the seller so blame me.... blatant plug follows :-) I have to clear out my shed so I'll be dumping on eBay.com.au various bits and pieces. Predominantly it will be DEC UNIBUS modules, papertape, CAPS-11 operating system, plus technical documentation. Stuff is coming out in random order. E.g. some of the -K series laboratory modules have been listed but I've only just found the panels and some of the cables. Really only of interest to Australians are the heavy/bulky/delicate items like the PDP-11 system with the LPS-11 / TU60, or FABRI-TEK Model 11 Add-On Memory System, etc., that are being listed as local pickup. There will some Heathkit (H10 papertape readers/punches and a 3400A microcomputer trainer) plus should be some HP GPIB gear. The Tektronix gear has already gone. I do not have any CM-11 card readers, just some of the UNIBUS interface modules. Regards, Garry

14 years, 4 months

Wanted: Graphics card and drive sled for RS/6000 7046-B50

by andreww591＠gmail.com

I recently bought an RS/6000 7046-B50. It didn't have a graphics card installed (I can use it over a serial console, but I would prefer to be able to use a graphical console). It is also missing the drive sleds. Does anybody have a graphics card or drive sled that would work with it?

14 years, 4 months

chemistry simulator on Apple ][?

by mcguire＠neurotica.com

A local friend is looking for an old chemistry simulator program for the Apple ][. Here's his description: > I'm trying to find a "chemistry simulator" program that I used to play > with on an Apple II way back in the day. I don't remember the name of > it, but I remember being able to build a decent "lab" out of parts and > pieces. I remember that the first lesson was an experiment to figure > out why the fertilizer ship in Texas City exploded after an onboard > fire. Does anyone know what this might've been called, or better yet, does anyone have a copy? -Dave -- Dave McGuire Port Charlotte, FL

14 years, 4 months

Taking offers on PDP-8 (straight-8)

by sellam＠vintagetech.com

A straight-8 has come up for sale. I am representing the seller. I have photos and details. If you're interested please e-mail me and I'll send over some information. Preliminary photos are here: http://siconic.com/computers/PDP-8/ We'll take opening offers and if there's one good enough then we'll cut to a straigt (8) sale. Otherwise, it'll move on to a VCF web auction at a future date. Thanks!! -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

14 years, 4 months

HP 2671 Graphics ROM

by hp-fix＠xs4all.nl

I aquired a HP 2671A thermal printer and know that there should be an upgrade ROM to 'upgrade' it to a HP 2671G. Thanks to Tony excelent work on HPCC CDROM i have the schematics and was able to fix the head positioning circuit. One of the driver transistors (TIP 122) was bad after replacing it and cleaning the printer it works fine. But now I want to use it for printing graphics (diagrams) and would be very happy whith an image of the graphics ROM. -Rik PS. don't shoot me if it appears a second time, I used the first time the wrong email address.......:-(

14 years, 4 months

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test-drb March 2010