test-drb September 2008

test-drb@ccmp.vtda.org

220 participants
323 discussions

by aek＠bitsavers.org

The Texas Instruments integrated circuit is 50 today. I have no idea what a "MicroChip" is. "Microchip" is the company currently making PIC microprocessors.

15 years, 10 months

ISO: NEC UPD72070 IC

by cclist＠sydex.com

Anyone have a spare one of these chips? This was used as the floppy controller on the AV Macs. Contact me off list if you've got one that you are willing to part with. Thanks! Chuck

15 years, 10 months

Osborne 1

by tponsford＠rnsmte.com

So I was complaining to my significant other on the recent dearth of classic computers at out local university auction! Well the computer gods must have heard me as I got a working Osborne 1 in great condition, with even the cp/m disk in the floppy drive for $15.00 on Tuesday!! I am now only missing a KayPro for my "luggable" collection to be mostly complete!! Cheers Tom

15 years, 10 months

Suggestions for cleaning hundreds of socketed chips?

by derschjo＠msu.edu

Hey all -- I've gotten the power supply in one of my ND-812s running (thanks for the help w/the 1103 data which helped verify the voltages) and it appears to be within spec under load (correct voltages, no ripple in the output, etc...) so I powered the machine on and despite having my fingers crossed, the machine does not run. (No real surprise there). Random lights on the front panel, and basically no response to any toggle switches. I started pulling out and reseating the chips on the main CPU board and powered it up after every few rows, and every time the behavior was slightly different, so I'm fairly sure that the sockets and chips aren't all making good connections anymore. Seems like solving this problem would be a good place to start. The problem is that there are 25 rows of 13 chips each (all socketed), in very close proximity to one another. The chips are in sockets with wire-wrap pins underneath -- the underside of the main CPU board is a maze of wire wrapping. Most of the chips have date stamps between 1971 and 1973, but luckily most of them aren't corroded to the point where they're falling apart. How would you suggest cleaning the sockets and the chips to ensure good connections? Thanks, Josh

15 years, 10 months

Another disk imaging project

by lynchaj＠yahoo.com

Hi, I came across the following message from Dave Dunfield from a couple of years ago during a search related to the Z80 i8272 home brew project I am working on. I recently got the i8272 FDC to reliably read sectors from a MS-DOS formatted 5.25" floppy disk drive. This project is underway but I am a long ways from completion. During the debugging of my system, I have noticed that there some possibly useful raw disk signals being generated by the data separator chip. These could be rather easily exported to support a disk imaging project were anyone interesting in such a thing. The signals are going *into* the i8272 (NEC 765) for processing and are raw data signals. The i8272 would not be used to process the data. This *potentially* opens up access to any FM/MFM encoded disk even hard sector. I don't know about other formats such as GCR, M2FM, RX02, etc. Here is what I propose; my SBC and Disk IO board generates intermediate product signals such as "separated clock", "separated data", "clock out", "index", etc and buffer them through a 74LS367 or similar. I am willing to make *MINOR* modifications to the Disk IO board to export these signals via a connector and even add one or two small chips to the design to improve signal quality. I am *NOT* willing to make major modifications to the design at this point as I have a mostly working system and do not want to start over. The intermediate disk signals could, *I believe* be imported into a PC parallel port with "clock out" (typically 500 KHz for MFM DSDD, 250KHz for FM, etc) being used for latch signal. I think they are also slow enough to be practically captured by the PC parallel port. The PC could then sample the parallel port at high rate (interrupt driven? DMA?) to read the signals and create a disk image from the data. Again, the i8272 would not process the signals so they would contain all the data the i8272 processes but will not pass along such as header info, IDAM, CRC, true gap length, etc. I could even include true "raw read" signal which would be the bit transitions straight from the drive however due to the high sampling rate required to accurately capture it I really don't think it would be much use. Would it be possible and/or practical to make a PC based disk imaging tool using the SBC as an intermediate stage? Please note, I am only offering to make minor modifications to my SBC and Disk IO board to support such a project, not to conduct a PC based disk imaging software development project myself. I wrote some hard sector Catweasel programs earlier for Heath, Vector Graphic, and NorthStar so I have some familiarity working with raw disk data, however, the home brew Z80 project is using up all my hobby time. If you are interested please reply here or contact me. Thanks! Andrew Lynch PS Here is the Z80 i8272 home brew project I am working on for background information http://groups.google.com/group/n8vem?hl=en Another disk imaging project Dave Dunfield dave04a at dunfield.com <mailto:cctech%40classiccmp.org?Subject=Another%20disk%20imaging%20project&I n-Reply-To=> Wed Aug 3 04:58:06 CDT 2005 * Previous message: ImageDisk and some 8' images posted * Next message: Another disk imaging project * Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] ________________________________ Hi Guys, I'm really getting fed-up with the limitations of the PC floppy disk controller. Here's another idea I've had on the back-burner for quite some time, I've mentioned to a couple of you during private correspondance, but here it is for open discussion. The idea is to make a small single-board computer with a microcontroller, a WD2793 or similar floppy disk controller, enough memory to buffer a few tracks, and a high-speed serial port for communication with the PC. The board would have connectors for 5.25"/3" drives and 8" drives, and would properly interface to all drive types. Firmware would be developed to provide read/format/write/analysis capabilities around the more powerful WD chip. Images would be transferred via the serial connection to and from the PC. This should allow us to archive soft-sector formats that are not compatible with the PC, and also to perform these functions under virtually any PC environment. I just haven't had time to design and build the board ... anyone else interested in working together on such a project? Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html

15 years, 10 months

ECC on MFM drive

by ra9yer＠yahoo.com

>> Yes. Indeed. I checked it again and it is the regular >> CRC circuit with unusual initial value and polynomial. > What are these values? They are not documented in the data sheet. The polynomial is 0x140a0445 (x32+x28+x26+x19+x17+x10+x6+x2+1), the initial value is 0x9dcd57c0. It is need to do following steps to check crc: 1 Init sift register by initial value 2 Process 0xf8 (MSB first) 3 Process 512 bytes of data 4 Process 4 bytes CRC. If everything is ok then value in the shift register will be zero. Alexander.

15 years, 10 months

DEQNA/DELQA cab kit with DEUNA/DELUA?

by oldcpu2＠rogerwilco.org

> The DEQNA and DEUNA print sets have been on-line for some time. > > Don't forget the archives and links at: vt100.net/manx > Here is the DEUNA link: > > http://vt100.net/manx/details/1,3463 As for locating the DEUNA information, thanks to an earlier respondent, I have dragged a copy of that out of bitsavers.org. For some reason, I just couldn't find it. I must have looked in various PDP subdirs, the ethernet subdir, but missed it in the unibus subdir. Doh! [BTW, a huge thank you to Al and Paul for building and maintaining such valuable resources. Where's the tipping jar, eh, gentlement?] Thanks to all who replied to my original post. It is clear that the cab-kits for QBUS modules are more or less usable with UNIBUS modules. That's the news I was hoping to find. It'll still be a while before I'm ready to test it all out on the 11/750, due to ongoing power supply hickups and troubleshooting, but it shouldn't be long now. Jared

15 years, 10 months

Okay, THIS is the final VCF East reminder

by evan＠snarc.net

Very last pre-show email ..... if you live within a few hundred miles of the Jersey shore, and you dig vintage computers, then don't be a putz! Come to the VCF East 5.0 this weekend. Tickets are 10 bucks for one day or 15 for both days. Free for 17 and younger. Parking's free too. Saturday is usually the busier day, but on Sunday (at 11:30) is a speech by Bill Mauchly, who's the son of John Mauchly, of ENIAC and UNIVAC fame. We're also opening the computer museum here in "beta" mode. More info is at the usual spot: http://www.vintage.org/2008/east/ I'm WAY too busy with final details to check back on cctalk, so if anyone has questions, please just call my cell phone, 646.546.9999. - Evan K.

15 years, 10 months

Another disk imaging project

by lynchaj＠yahoo.com

Andrew Lynch wrote: > The intermediate disk signals could, *I believe* be imported into a PC > parallel port with "clock out" (typically 500 KHz for MFM DSDD, 250KHz for > FM, etc) being used for latch signal. I think they are also slow enough to > be practically captured by the PC parallel port. The PC could then sample > the parallel port at high rate (interrupt driven? DMA?) to read the signals > and create a disk image from the data. Again, the i8272 would not process > the signals so they would contain all the data the i8272 processes but will > not pass along such as header info, IDAM, CRC, true gap length, etc. The Disk2FDI project has already done this; give it a look to see if it applies to your situation. -- Jim Leonard (trixter at oldskool.org <http://www.classiccmp.org/mailman/listinfo/cctalk> ) http://www.oldskool.org/ Help our electronic games project: http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/ A child borne of the home computer wars: http://trixter.wordpress.com/ -----REPLY----- Jim, Thanks for the reply. I already have a Catweasel and programs to read hard sector disks so I really don't need another disk imaging utility. My intent was to offer to contribute if anyone were interested in the CCTALK community to try again on a disk imaging project. The modifications required to my Disk IO board *appear* to quite minor to get access to the raw disk signals so it seemed like a good opportunity. What I had in mind was a low cost, open project, open source, available hardware and software information made of common parts for everyone. Sort of in the spirit of the N8VEM project but with a different theme. However, I realize how these projects have ended on CCTALK in the past and I can see there is no interest now so I'll just let it pass. My hobby time is limited and I have choose carefully what I work on like everyone else. Thank goodness for the Catweasel! Andrew Lynch

15 years, 10 months

Does anyone have an electronic copy of the "OS/8 Software Support Manual"?

by ethan.dicks＠usap.gov

Hi, all, I have my sbc6120 here and wanted to do a little OS/8 programming, but I think I'm stumped for a particular bit of doco - according to the "OS/8 System Reference Manual" (DEC-8-OSRMA-A-D), the User Service Routine is documented in the "OS/8 Software Support Manual" (DEC-8-OSSMA-A-D). I've found many OS/8 docs on Highgate and Bitsavers (DEC-S8-OSSMB-A-D, the 1974 "OS/8 Handbook", memos, etc.), but not that exact one. The reason why it matters is that if you want to do file I/O, directory lookups, etc., you use the USR. For stuff that doesn't depend on OS/8 filesystem operations, there's plenty of info out there for FORTRAN, BASIC, FOCAL, assembler, etc. Imagine trying to program in UNIX without knowing how to setup and call stdio routines. That's kinda where I'm at. I've found one or two narrow examples where some code fragments call the USR for a particular function, but I really just need the Software Support Manual. Thanks for any leads, -ethan -- Ethan Dicks, A-333-S Current South Pole Weather at 9-Sep-2008 at 00:00 Z South Pole Station PSC 468 Box 400 Temp -80.5 F (-62.5 C) Windchill -112.5 F (-80.3 C) APO AP 96598 Wind 7.1 kts Grid 104 Barometer 672.9 mb (10897 ft) Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html

15 years, 10 months

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test-drb September 2008