test-drb July 2000

test-drb@ccmp.vtda.org

155 participants
521 discussions

by cem14＠cornell.edu

This is OT in that the piece of hardware that I'm looking at (matrox millenium pci card) is newer than 10 years. On the other hand, any comments on this might be useful for older equipment as well. Here's the scoop: the video card in my home computer suddenly started acting flaky. The image flickers and has diminished brightness; at first I thought that it was the monitor, until I noticed that the area inside the dialog window that pops up when operating the setup menus in the monitor does not flicker and has normal brightness. Aha, cable or connector, I thought. So I tested another monitor. Exact same symptoms on the second monitor. Ok, then a cold solder joint in the card. I extracted the card and had a good look at it. Nothing looks wrong. I put the thing back in and it still had the flickering. Then, all of a sudden, brightness jumps back to normal and everything works fine for the rest of the session. Next day, I power up, and several hours later the symptoms reappear suddenly. I am thinking that the output of the RAMDAC is being severely affected by something that diminishes its swing. As far as I can tell, all colors are affected uniformly. The flicker is random, does not appear to be tied to a given frequency, and seems to affect the whole screen (refresh is currently 85 Hz; changing it does not alleviate the problem). So I wonder if there is some oscillation in the output of the RAMDAC or an internal short that limits the swing or what. Has anyone seen this sort of failure before? carlos.

23 years, 10 months

Friden help

by aw288＠osfn.org

Does anyone on the list have any experience with Friden Automatic Calculators? I have been fooling around with one, and it mostly works, but every few minutes locks up. I am not sure what is causing a problem, as the machine is quite complex. It only locks up when calculating. I am sure it needs a lube job, but at this point all I have done is bathe the whole thing in WD40. When things are going well, I will give it a real lube job. William Donzelli aw288(a)osfn.org

23 years, 10 months

Tim's own version of the Catweasel/Compaticard/whatever

by CLASSICCMP＠trailing-edge.com

Hi folks - The topic of reading or writing older "odd" disk formats (hard-sectored, GCR, whatever) comes up here pretty often. And often the discussion leads towards the Catweasel floppy interface (currently available commercially, as I understand) or the Compaticard interfaces (not currently being manufactured, as I understand). I've recently "modernized" my foreign format disk reading hardware. The idea of both the "old" version and the "new" versions are very similar to each other, and to what other tools like the Catweasel and the Compaticard do: Data from a floppy disk drive comes as a series of pulses on the read data line. All these circuits (using different means) buffer up to an entire track of data in RAM, and then allow a user program to look at the buffer and analyze the data on its own terms. They also allow control over rudimentary floppy functions such as step in/out, load head/start motor, etc. *I* buffer the pulses on the read data line by simply recording a "1" bit if there was a pulse in a window, and a "0" if there wasn't. I sample at 4MHz, meaning that a complete revolution of a floppy requires most a megabit of RAM. I also buffer information such as index pulse data (essential for decoding many hard-sectored floppy formats.) The bit rate from most standard floppy formats is roughly 500 kHz, meaning my 4 MHz sample rate oversamples by a factor of 8 or so. Yes, it's overkill for many applications, but I want to be sure that all information on the floppy is faithfully represented in the buffer. Besides, many GCR and some MFM variants use half- or even third-fundamental-frequency components (sliding the pulse in the window to encode more data without increasing the clock rate) and oversampling is necessary for these formats. Other buffers (I believe the Catweasel falls in this category) record the times between successive pulses in RAM, instead of the "raw bits". My "previous generation" buffer had a megabit of SRAM and interfaced via a 16-bit-in and 16-bit-out parallel interface (usually to a DR11-style interface on a PDP-11). The megabit of SRAM was made up of a whole bunch of 2k*8 SRAMS, meaning that just the buffer memory required a couple of sizable PC boards. (If you're familiar with the technology, you'll get the idea that "previous generation" buffer was based on chips readily available around 15 years ago.) My "new generation" buffer has the same megabit of SRAM - but now in a single SRAM chip - and interfaces via a PC-clone bidirectional parallel port. Other than the big SRAM chip, the rest of the buffer is just eleven SSI and MSI HCTTL IC's. The eleven chips form the PC-side interface, the floppy-side interface, the timing clocks, the buffer sequencer, and the buffer address (17 bits) counters. So how is my buffer different than, for example, the Catweasel? 1. The Catweasel uses some custom LSI parts, as far as I can figure out. My circuit is much more "hackable", anyone with a TTL databook can figure out what it does and improve on it. Or you can build one yourself from scratch. (Other than the 128K*8 SRAM, all the other parts were literally purchased from the local electronics shop. Heck, most of the chips can be bought at Radio Shack!) Total cost for the chips in my buffer is about $30.00, about half of that in the SRAM chip. 2. The Catweasel uses a proprietary, largely undocumented programming interface. My circuitry is entirely open, and I think it's pretty easy to program. (My first hack at acquiring data with the new buffer was dashed off in about half an hour under QBASIC.) 3. The Catweasel requires a bus slot inside a PC-clone. My new buffer uses a much more general purpose parallel interface. So you can hook it up to a laptop, or even to something that isn't a PC-clone at all. Those are what I see as advantages over the Catweasel. There are also some disadvantages: 4. You can't just go out and buy my buffer, but you can buy Catweasels off the shelf. 5. My buffer is strictly "read-only" as I use it. I think the Catweasel (and Compaticard) both allow writing. Would it be worth writing up my new floppy disk data buffer so that others could improve on it? Would anyone be interested in unstuffed and/or stuffed PCB's? Should I give it a name? (The "Timweasel", anyone? I gotta think of a better name!) -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

23 years, 10 months

need homes (fwd)

by vcf＠siconic.com

Stuff up for grabs. Please contact the original sender. Reply-to: crx_runner(a)hotmail.com ---------- Forwarded message ---------- Date: Tue, 04 Jul 2000 12:41:24 PDT From: Dave Broadbent <crx_runner(a)hotmail.com> Subject: need homes I have the following to give away: I had started a collection, then decided to stop. I am located in Souderton, PA (near Phila) Apple 111+, with monitor, with three additional drives. I never tested this to see if it works. Compaq Portable, the first model, have two, one works, one does not. Franklin Ace 1000, with BMC monitor(Aug, 1982), with two Rana System 5 1/4 drives, with Gemini 10 printer. This I am sure works. Dave work no. 215 540-0800 ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... VCF 4.0 is September 30-October 1 San Jose Convention Center, San Jose, California See http://www.vintage.org for details!

23 years, 10 months

Tim's own version of the Catweasel/Compaticard/whatever

by CLASSICCMP＠trailing-edge.com

>For quite some time I've tried to persuade Eric Smith, who's quite >knowledgable about programming the SCENIX SX processor, to write some >firmware that would create, functionally, a FDC chip out of one of these >ultra-fast single-chippers. "Better" is the enemy of "good enough". If I can throw something together in an afternoon out of TTL chips from Radio Shack, why go to the effort of creating what amounts to a custom chip? Maybe my priorities are too much on the "just do it" side, and not enough on the "do it Dick's way" side :-). >Interpreting it in light of the modulation, data format, data rate, etc, is >quite involved, but certainly achievable, though someone has to undertake to >write the code with which to accomplish this. The code obviously varies depending on the encoding method, but my method - a completely public circuit design with easy interface to a wide variety of computers - allows the user to write the decryption code in whatever he/she might be familiar with on whatever platform he/she wants. > Having the entire diskette >sampled as has been suggested, a track at a time means that one's computer >can, at its own pace, reduce, interpret, reformat, etc, the data prior to >writing it to a duplicate. The reformatting of the data into its original >format offers the advantage of phase coherency between sectors so the PLL on >the controller doesn't have to shift phase between sectors. That will make >the job easy in a case where the PLL has, over time, drifted off its nominal >data rate. ??? There is no need for a hardware PLL if you oversample by a factor of a few. >There are, IIRC, 10416 byte-times, nominally in an 8" FD track at MFM. at >16x ovrsampling, that's a fair amount of data. That's absolutely true. But RAM chips are fairly cheap these days, and I took advantage of that in my design. > While there are a number of >256Kx8 SRAMS out there, they're not likely to be lying in the corner unused. I used an ISSI 62C1024-7, a 128K*8 70ns 32-pin DIP, and it's good enough for me. Cost was $12.00. Looking in my Digi-Key catalog, it seems you can get 512K*8 parts for about $15.00 today, but they're in TSSOP's which aren't so quickly breadboarded for me. (Though they are the obvious solution if you transfer my design to a PCB layout.) I'm sure a fair number of people on this list have access to unused 486 motherboards with socketed cache RAM parts in the 32K*8 to 128K*8 range. These oughta do fine too. >I recommend, therefore that such a circuit be devised with DRAMS. Again, "better" is the enemy of "good enough". I made my circuit with parts that were easily available to me, and I decided that it wasn't worth the effort to build a DRAM controller when SRAM is so cheap. (And SRAM kept the parts count down, too...) You obviously have different priorities. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

23 years, 10 months

newbie intro - free TRS stuff

by aclark＠envirolink.org

Hello to all fellow classic computer enthusiasts! I just heard about this mailing list last week. I'm glad to have found such an active discussion group. My primary interest is the Apple ][ & /// series. (I am a member of the venerable Washington Apple Pi.) I would be happy to swap private email with like-minded folks on this mailing list. I am always in search of Apple hardware for my collection, please send email if you have such to unload. Suggestions of individuals and companies who deal in old Apple hardware are also always welcome. I enjoy the old machines, but have been driven nearly mad trying to find hardware that people are actually willing to sell. ATTENTION TRS COLLECTORS: last year I inherited an enormous quantity of software and hardware from an old TRS business network. The console, terminals, cards, and printer are gone. All that remains is available for the cost of shipping, to good homes. I have five large boxes of 8 inch disks, with multiple copies of Xenix, with manuals. Many other boxes of system manuals and other sundries are also available. I also have an external hard drive, "Tandy Thirtyfive Meg Disk System." While I do not collect Tandy, I just can't bear the thought of all this stuff going to a landfill. I know how I feel when I am occasionally subjected to someone's story of how a friend of theirs had a "bunch of old Apple stuff, but finally just threw it all away last year." Anyone within driving distance of south-central Pennsylvania is welcome to come and look at everything. It's all free. If you want it, just arrange to come and pick it up. Regards & Happy 4th, Arthur Clark

23 years, 10 months

Vintage Computer Festival 4.0

by vcf＠siconic.com

Vintage Computer Festival 4.0 September 30 through October 1, 2000 San Jose Convention Center San Jose, California Mark you calendar! The fourth annual Vintage Computer Festival is scheduled for Saturday, September 30th though Sunday, October 1st at the San Jose Convention Center in San Jose, California. The Vintage Computer Festival is a celebration of computers and their history. The event features speakers, a vintage computer exhibition, a vintage computer marketplace, and contests like The Nerd Trivia Challenge. We showcase all different types of computers for all differents kinds of platforms in all different shapes and sizes. REGISTER EARLY AND SAVE! Since you're already a VCF fan, we'd like to extend an early-bird registration offer to you. Register by July 15th and pay only $15 per person (after July 15th the fee will jump to $20 per person). Your registration includes complete event access, including speakers, the exhibition and the marketplace. And just like last year, the first 32 registrants will receive a VCF t-shirt! Act fast to secure your early registration and a free VCF t-shirt. We've made it easier than ever for you register online as we are now accepting credit card payments. Visit the VCF website for complete details. EXHIBIT YOUR VINTAGE COMPUTER Vintage Computer Collectors: we want you! Exhibit your favorite computer in the Vintage Computer Exhibition. Prizes will be awarded in 12 different categories, as well as a Best of Show prize which includes $50 cash! For complete details on the VCF Exhibition, visit: http://www.vintage.org/2000/exhibit.html To see the exhibits from VCF 3.0 go to: http://www.vintage.org/exhibit99.html BUY/SELL/TRADE AT THE VINTAGE COMPUTER MARKETPLACE Do you have some vintage computer items you'd like to sell? Whether you rent a booth or sell on consignment, the Vintage Computer Marketplace is the premier venue for selling old computers and related items. If you would like to rent a booth or inquire about consignment rates, please send e-mail to vendor(a)vintage.org for more information or visit: http://www.vintage.org/2000/vendor.html CHECK OUT THE NEW SITE! If you haven't visited the VCF website in a while, come on over and have a look at the completely new design. You'll find it easier to navigate and easier to find the information you're looking for. We've got plenty of good stuff to read and hundreds of new links to explore vintage computing on the web. We're constantly adding new content. Stop on by for a visit! TELL A FRIEND! TELL A FRIEND! TELL A FRIEND! We really hope to see you at VCF 4.0! And remember, tell your friends!! Vintage Computer Festival 4.0 September 30th through October 1st, 2000 San Jose Convention Center San Jose, California http://www.vintage.org

23 years, 10 months

Tim's own version of the Catweasel/Compaticard/whatever

by allisonp＠world.std.com

> *I* buffer the pulses on the read data line by simply recording >a "1" bit if there was a pulse in a window, and a "0" if there wasn't. >I sample at 4MHz, meaning that a complete revolution of a floppy >requires most a megabit of RAM. I also buffer information such as >index pulse data (essential for decoding many hard-sectored floppy formats.) Sounds like a variation of the "Wells" controller ca. 1976, used 1x4k memory to buffer up all the the disks bits. Lots of SSI ttl to serialize/deserial the bits in and out of the ram but otherwise simple and functional. Check early BYTE or KB for the article on it. His design was limited to mfm (then the only thing used) but it would take little to deal with that. >Would it be worth writing up my new floppy disk data buffer so that >others could improve on it? Would anyone be interested in unstuffed and/or >stuffed PCB's? Should I give it a name? (The "Timweasel", anyone? I >gotta think of a better name!) If you would, please. I'd find it interesting. Allison

23 years, 10 months

languages

by edick＠idcomm.com

English is my second language, though I've been using it as my primary language since I was 6. Because I learned it as my second language, I've developed into one who's somewhat stilted in his usage of the language, and also one who's very much aware of the application of grammar, syntax, and orthography. I am, therefore, thoroughly convinced that American English, if it follows the current trend, will degenerate into a sequence of monosyllabic grunts and whines by the time another couple or three generations have passed. Just look at the more recent additions to the Webster International Lexicon of the English language: words like "duuhh" ... Dick -----Original Message----- From: Gary Hildebrand <ghldbrd(a)ccp.com> To: classiccmp <classiccmp(a)classiccmp.org> Date: Wednesday, March 08, 2000 9:37 PM Subject: languages >Interesting dialog on languages . . . . > >I myself have barely mastered English, american style. Somewhere along the >way I took three years of French in High School, the result being that my >English grades shot through the roof. Seems learning a foreign language >helps one master English grammar. Maybe the problem is that one can't >speak correct English in the first place. > >As for the Morse code, I've talked to many people who's answer was "I don't >think I can learn the code." It isn't a matter of skill -- five year old >kids have learned Morse code. I call it a case of 'wanna'. If you wanna >you can learn anything. But since the FCC deregulated the Amateur licencing >structure, getting 5 wpm is fairly easy, if you wanna. > >Gary Hildebrand WA7KKP >

23 years, 10 months

Archives of OS/360-ish public domain software?

by CLASSICCMP＠trailing-edge.com

Are there any on-line archives of OS/360 software in the public domain? I'm thinking not only of operating system software distributions (which are rumored to be in the public domain), but also of user-group collections of software for these beasts. I'm also interested in software for previous generations of old iron, like IBM 1401's, etc. I've asked around at a couple of prominent computer museums, but they all just shrug their shoulders when I ask them how they archive and index the original software, like they've never considered it to be important. I really feel like I'm talking to all the wrong curators, because they seem to have no interest in the subject at all. I've heard of the Hercules emulator project, but I don't know what software they have archived so far, or what efforts they are currently making. If someone could point me towards an index of their software archives I'd appreciate it. I consider myself to be an expert at archiving DEC-related software, and often am involved in all sorts of projects in that sphere that benefit everyone from hobbyists to those with legal cases, but I know little to nothing about what archives of old IBM stuff are available. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

23 years, 10 months

← Newer
1
...
45
46
47
48
49
50
51
52
53
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 July 2000