test-drb September 2007

test-drb@ccmp.vtda.org

220 participants
406 discussions

by dm561＠torfree.net

Anybody in Las Vegas who'd be willing to help a nice lady doctor who's trying to read some old 5 1/4 WP5.1 disks on her 386 with a flaky FDD? Please? Contact me off-list for her info if you think you can help. Mike in Toronto (a little too far away ;-(

16 years, 10 months

Goodwill Computerworks Museum Pictures

by daultman＠tx.rr.com

I just found a post about visiting the Goodwill Computerworks from Aug 2000 while seearching for information on an IBEX 7202 CP/M I have. I have looked at vintage-computer.com and vintage.org, EBay, and general searches many times. Yours is the first I've found referencing this computer I have. Can you tell me more about it? Who might be interested in it and the many programs I have with it?

16 years, 10 months

Seven segment display history

by pdp11＠saccade.com

One thing I've always been really curious about is who invented the seven segment display. Not a particular implementation of it, but the graphic design concept that seven bars are all you need to display the digits 0 - 9. I'd always assumed it was something that originated from the creation of electronic calculators. The first Friden EC-130 for example, uses seven segment patterns on a CRT (machines prior to that used Nixie tubes). Well, leave it to Don Knuth to dig up a much older reference. While browsing his web pages, I noticed a reference to patent 974,943 by F.W. Wood, issued in 1910(!). It describes an electro-mechanical "Illuminated Announcement and Display Signal" with a segmented display. Wood actually uses eight segments (so his "4" has a slanted top), but other than that, it's exactly the same design as the digits today's cheap watches and calculators. Patent (you may need to register first): http://www.freepatentsonline.com/0974943.pdf Cheers, jp

16 years, 10 months

IBM 4865 (External 3.5" floppy) power pigtail connector

by mbbrutman-cctalk＠brutman.com

I've acquired an IBM 4865 drive for my 5160 XT - it is a 3.5" external drive. I've got the 1.44MB version which is wrong for the XT, but with the correct media (1MB diskettes) it might work. Besides the normal 37 pin D shell connector that goes to the back of the floppy controller this drive has a little 4 connector pigtail to provide operating voltage for the drive. I've picked the drive apart and I think I know what the pins on the power pigtail are supposed to be. I'd like to find a nice matching socket for the pigtail instead of just hacking it, but after an hour into the world of Molex and Amphenol I've decided to ask for help ... The picture can be found here: http://brutman.com/dscf6030.jpg Thanks in advance, Mike

16 years, 10 months

Cromemco & Persci drives (was PS/2 interface &c)

by dm561＠torfree.net

Date: Tue, 18 Sep 2007 22:56:31 -0400 From: "Roy J. Tellason" <rtellason at verizon.net> Subject: Re: Cromemco & Persci drives (was PS/2 interface &c) <snip> >> it's sometimes convenient to hook up a known good 5 1/4 drive to check out >> the rest of the system and get it up & running before you dig into the 8". >> Also makes it easier to make disks from PC images if you need them. >It's been a really long time since I played with it, but I remember the rest >of the system working okay, more or less. There's a CPU board and a 64K RAM >board in there, besides the FDC (which if I'm remembering right also has the >printer port on it). Does 16FDC sound right? 16FDC sounds right but this takes us back to the original topic: that DB-25 is the RS-232 console port, not a printer. >> If there's no HD you might have trouble finding 12V though & need a >> separate supply or regulator; an external powered 5 1/4 disk in a nice >> enclosure is a useful peripheral for a System3. >I suppose I could rig one up, but I don't know about hacking together a BIOS >for that machine. I never did get into that stuff all that much. Well, you wouldn't have to hack the BIOS but (assuming you're running CDOS) you'd need a 5 1/4 CDOS image; I think Dave D has some on his site. Good luck. mike

16 years, 10 months

Apple IIc+ boot disk for DOS3.3

by HGoff＠2-10.com

Do you stock this diskette?

16 years, 10 months

did anyone else go to MIT?

by chrism3667＠yahoo.com

that show is not what it used to be. Certainly not worth the ~300 mile drive. It used to be in a different location and was at probably 2x as big. Did talk w/some interesting people. I met a guy who has 3,000 computers, including some VERY big iron. Can you say you know anyone w/this many puters? Can you? I think not. MUAHAHAHAHAHAHA ____________________________________________________________________________________ Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545433

16 years, 10 months

EPROM Erasers?

by trag＠io.com

>Date: Sun, 16 Sep 2007 06:57:40 -0700 >From: dwight elvey <dkelvey at hotmail.com> > A carbon arc would work as well but I've not seen these >since they've stopped using these in search lights. >Dwight Back in elementary school one of the library books had interesting projects in it. One project was to remove the carbon rods from four 'D' cells. They're about 1/4" - 3/8" in diameter and run the length of the cell. It's a bit of a trick to extract them without breaking them. Once you have four carbon rods, suspend two in a jar of salt water. Grip the other two, each with its own wooden clothes pin (the spring type, not the slot type). Now steal a heavy duty electrical cord from something like Mommy's clothes iron. Attach one lead of the cord to one of the carbon rods in the jar of salt water. Connect the other lead to one of the carbon rods held by a clothes pin. Now use a spare length of heavy wire to connect the remaining two carbon rods together. Plug the cord into the wall. Now carefully touch the tips of the two clothes pin carbon rods together and then slowly draw them apart. TADA! Carbon arc. Vary the salt content in the jar to adjust the power. I don't recall the instructions saying anything about not looking directly at the arc. Perhaps this method doesn't generate enough UV to be useful/harmful? I spent a fair bit of time staring at the thing. Thirty-five years later I haven't noticed any vision impairment, but maybe I was young enough for my retina to recover. It was quite the attention getter at the ES science fair. I suspect books in grade schools don't contain cool/dangerous projects like this any more. I only electrocuted myself once or twice by touching the live bits of the contraption... Jeff Walther

16 years, 10 months

Repro Cromemco joysticks...

by wh.sudbrink＠verizon.net

Hi All, I want to build a couple of reproduction (work alike) Cromemco joystick consoles for two reasons: 1) I don't have any real ones. 2) I'll be able to let the "unwashed masses" (my children included) play various games with worrying about them getting destroyed. To this end, I've looked at the pdf of the manual and (to my delight) discovered that I have all of the required parts. Well, almost. Two things: 1) The manual calls for a 45 Ohm QUAM speaker. All I have are plain old run-of-the-mill 8 Ohm internal PC speakers. My ignorance of basic electronics shines through... 30 minutes of googling and I'm not sure what QUAM means. Anyway, can I substitute the speaker? With some modification to the schematic? 2) The manual does not specify the pot values on the joystick. The joysticks I have have 100K Ohm pots (thanks Tim Shoppa!). Is that value correct? Is the value important? Can I adjust for it on the D+7A or in the circuit on the joystick side? Also, an esthetic question: are the joysticks on the original self-centering? Thanks for any help! BTW: Both manuals (joystick console and D+7A card) are in the Harte repository. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.487 / Virus Database: 269.13.22/1013 - Release Date: 9/17/2007 1:29 PM

16 years, 10 months

Calcomp 1043GT plotter in Salem, OR

by cclist＠sydex.com

Just saw this one on Craigslist: http://eugene.craigslist.org/sys/425978406.html Cheers, Chuck

16 years, 10 months

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test-drb September 2007