test-drb April 2008

test-drb@ccmp.vtda.org

196 participants
307 discussions

by lynchaj＠yahoo.com

-----Original Message----- From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf Of der Mouse Sent: Tuesday, April 15, 2008 8:45 PM To: cctalk at classiccmp.org Subject: Gerber help sought Prompted by my latest project (a cable pinout sensor - just plug a cable into it and you get the pinout), I want to look into the possibility of having one-off PC boards made. Everyone seems to want Gerbers, but without documenting exactly what they are. I found a PDF describing "RS-274X", which appears to be most of it, but there are lots of conventions it doesn't describe. I've found indications that there exists some open-source software, but extracting documentation from code is a mess. I'm going to be asking various people whose addresses I've found in various places. But you people are documentation packrats, so I'm asking here as well: anyone have any such doc? /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B -----REPLY----- Hi, I recently had to do something very similar. Maybe I can help you with Gerber file generation. I have recently designed a PCB version of my Z80 home brew computer using a free/open source EDA program called KiCad. The latest version is excellent and now includes an autorouter & optimizer for PCBs. Get the latest versions from the sourceforge site as the "stable" version is pretty stale, I think. Linux and Windows versions are available. http://www.lis.inpg.fr/realise_au_lis/kicad/ It uses the awesome free PCB routing tool at: http://freerouting.net I have an example circuit board up on my project site. http://groups.google.com/group/n8vem The gerber files are bundled in the ZIP file. KiCad includes a gerber file viewer utility. KiCad and freerouting.net are a great combination and are easy to use and learn. I was able to learn the program from a total cold start to nearly complete project (schematic, PCB layout, part selection, routing traces, gerber file creation, drill file, etc) in just a few days. My plan is to have the PCBs made at (they seem pretty inexpensive, if there are cheaper / better options available, I would like to hear them) https://www.barebonespcb.com/!BB1.asp Thanks and good luck! Andrew Lynch PS, if there are any experienced CCTALK veterans who'd like to review & critique my home brew Z80 SBC design, I would much appreciate your comments. I have completed PCB routing & optimization but haven't placed the order yet. A little peer review from knowledgeable person(s) would definitely be a big help. I'd rather find the faults *before* the boards a cut!

16 years, 8 months

Looking for a LM4250H 8 Pin DIP or A real good substitute

by lynchaj＠yahoo.com

Wed Apr 16 08:11:52 CDT 2008 * Previous message: Atari history * Next message: Looking for a LM4250H 8 Pin DIP or A real good substitute * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] ________________________________ I am Looking for a LM4250H 8 Pin DIP or A real good substitute. I found a Data Sheet but having trouble locating any Parts. I am hoping someone has one in their Parts Box TIA Bob in Wisconsin USE trebor07 at execpc.com <http://www.classiccmp.org/mailman/listinfo/cctalk> ________________________________ -----REPLY----- Bob, I bought some a while back from UnicornElectronics.com. They are really cheap parts and it fixed my home brew S-100 bus terminator with no problems. Apparently those op-amps get worn out over time and just die occasionally, I guess. At least replacing the one on mine worked. Thanks and good luck! Andrew Lynch

16 years, 8 months

Gerber help sought

by mouse＠Rodents.Montreal.QC.CA

Prompted by my latest project (a cable pinout sensor - just plug a cable into it and you get the pinout), I want to look into the possibility of having one-off PC boards made. Everyone seems to want Gerbers, but without documenting exactly what they are. I found a PDF describing "RS-274X", which appears to be most of it, but there are lots of conventions it doesn't describe. I've found indications that there exists some open-source software, but extracting documentation from code is a mess. I'm going to be asking various people whose addresses I've found in various places. But you people are documentation packrats, so I'm asking here as well: anyone have any such doc? /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

16 years, 8 months

Looking for a LM4250H 8 Pin DIP or A real good substitute

by trebor72＠execpc.com

I am Looking for a LM4250H 8 Pin DIP or A real good substitute. I found a Data Sheet but having trouble locating any Parts. I am hoping someone has one in their Parts Box TIA Bob in Wisconsin USE trebor07 at execpc.com

16 years, 8 months

Looking for a LM4250H 8 Pin DIP or A real good substitute

by cclist＠sydex.com

Date: Wed, 16 Apr 2008 11:17:07 -0500 From: "Robert J. Stevens" > I am Looking for a LM4250H 8 Pin DIP or A real good substitute. I found > a Data Sheet but having trouble locating any Parts. I am hoping someone > has one in their Parts Box TIA Bob in Wisconsin USE trebor07 at execpc.com My cross-reference charts say that the TI OPA704PA (in current production and available from Digi-Key) is a drop-in substitute. The Philips ECG944M may also work. Cheers, Chuck

16 years, 8 months

The history of the double sided floppy given under oath

by sellam＠vintagetech.com

I sent this to my friend Shrikant who worked at Shugart back during this time and this is how he replied: "Yes, I demonstrated and explained the reason why but the decision to use Tandon's technology was a business decision. We swapped the licenses for Tandon's "Bi-compliant" head actuator patent and Xerox/Shugart's "Band Actuator" patent of Warren Dalziel "I will explain more to you when I return.. "One lesson to learn from this episode was that as Goethe said in Faust and I only paraphrase him: One has to work to make one's own what we inherit from our forefathers. "In context of Shugart, the "Tri-compliant" design a la IBM was implemented without knowing its subtleties and slider/spring behaviour. I think Shugart did learn the lesson as far as egos would permit." I'll post the remainder of his reply when I receive it. -- 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 ]

16 years, 8 months

Gerber help sought

by les＠frii.com

There are two gerber standards, 274D and 274X. 274X has the aperture information embedded in the gerber file, 274D has a seperate aperture file. I have a program I wrote to merge 274D files and aperture files into a 274X file, as many board houses no longer accept 274D files. The PCB package I use only generates 274D files. http://www.lh1.org/autotrax/autotrax.html I use Protel Autotrax. This is a formerly commercial program, which is now public domain. It is a DOS application. It supports up to eight layer PCBs, with no limit on the number of components or board size (up to 32 inches by 32 inches). It has an autorouter, which I never use. I have created PCBs up to 12 inches by 12 inches with over 1200 components using this package. Although the 274 spec allows multiple layers to be placed in one file, I don't know of any board houses which support that format. I use a standard file naming convention, but board houses usualy like to get a text file listing which file is which layer. Advanced circuits has you assign layers to files when you upload your data. Here is a typical readme file: GERBER TOP LAYER FILE NAME ;FLUXGATE.GTL GERBER BOTTOM LAYER FILE NAME ;FLUXGATE.GBL GERBER TOP SOLDER MASK FILE NAME ;FLUXGATE.GTS GERBER BOTTOM SOLDER MASK FILE NAME ;FLUXGATE.GBS GERBER TOP COMPONENT MASK FILE NAME ;FLUXGATE.GOV GERBER BOTTOM COMP MASK FILE NAME ;FLUXGATE.GBO ASCII NC DRILL FILE NAME ;FLUXGATE.TXT NC DRILL TOOL SIZE FILE NAME ;FLUXGATE.TOL A friend of mine maintains a open source pcb layout program, available at: http://opencircuitdesign.com/pcb/

16 years, 8 months

Atari history

by jack.rubin＠ameritech.net

This was pointed to on another list - some great stories and a slightly different perspective on (late) DRI - http://www.dadhacker.com/blog/?s=atari+st Jack No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.0/1379 - Release Date: 4/15/2008 6:10 PM

16 years, 8 months

SGI INDY top lid in good condition?

by jlobocki＠gmail.com

hello, I am looking for the lid to an SGI indy, but cant seem to find one anywhere. does anyone have any they could sell me, or know where i could find one? thanks

16 years, 8 months

Chess

by cclist＠sydex.com

Date: Tue, 15 Apr 2008 12:08:06 -0700 > From: "Rick Bensene" > I played this a lot on weekends when I was the Cyber 73 weekend operator > at Tektronix. This was under KRONOS rather than SCOPE. I believe that the > console command was X.CHESS It used both CRT's, the left for a nice vector > display of the game board, and the right for a listing of the moves made > thus far, elapsed time, and for entering moves. I believe that the main > program ran all of the chess processing, and that a PPU program > communicated with the main program. When I got the Chess bootleg release tape from a friendly site analyst (they always got the good stuff first), I had to rework the display driver to work with our own OS, which used much of the PP code from Scope 3.1.6. It wasn't difficult, but the presence of a dedicated display driver required that one EDITLIB the driver into the system library--something you weren't likely to be able to do on someone else's system. I can't say for sure, but I believe that I was the one to modify the code to use the "T" display, so that Chess could be run without any special system modifications. I had to give up one or two fancy display features, but generally, it worked pretty well. > The Cyber 73 had two main CPUs, and 20 PPUs (10 for each CPU). The > CPUs were essentially 6600-design, with some enhancements for certain > types of vector operations, as well as dealing with shared main memory. Small nit, Rick. Depending on the model, the 73 was either a 6400 or 6500 (2 CPU) machine. It was the Cyber 74 that was the 6600 10- functional-unit system. You can check Bitsavers for the docs, but I'm certain of it. The "vector extension" wasn't really one--it was called the "Compare/Move Unit" or CMU. It really didn't do much other than give one the ability to perform non-word aligned moves and compares. It had no arithmetic capabilities (other than the compare). Really, no practical performance benefit on the 6600/74, but it made a difference on the serial-issue 6400/73. The fly in the ointment was that while it was standard on the 73, it was not available on the 74. In the COBOL run-time library, we had some fancy code worked out by Rick James that would check for the CMU (which was triggered by a no-op (46 opcode) with some nonzero bits in the normally-zero operand field. Detecting the thing was interesting. You couldn't say that "if it's not a Cyber 74/6600, then there's a CMU", since you still had the issue that the 6400 and 6500 didn't have it either. The technique was to code a word so that the first parcel was a CMU instruction (didn't matter what flavor), the second parcel was a no-op (46000) and the third and fourth parcels contained an uncondition jump. If a CMU was present, the next instruction would be taken from the next word; if not present, >from the succeeding parcels, which would cause the jump to be taken. Worked just fine until some idiot at Arden Hills decided to work up an FCO to the Cyber 74 to trap "CMU not present". Sigh--after that, it was determined as part of deadstart. Cheers, Chuck

16 years, 8 months

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test-drb April 2008