test-drb July 2005

test-drb@ccmp.vtda.org

257 participants
628 discussions

by jkunz＠unixag-kl.fh-kl.de

Hi. Is someone else attending http://www.whatthehack.org/ ? I am in the big BSD tent (field F), in front of the SGI O2 beside the NetBSD posters and devotionalia. http://wiki.whatthehack.org/index.php/BSD_Village -- tsch??, Jochen Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/

18 years, 10 months

MicroVax 3600 free for the taking, imminent disposal! HURRY!

by jzg22＠drexel.edu

A digital MicroVax 3600 and its requisite heap of media has recently been trashed by the physics department at Drexel University. It is sitting in the hallway of the 7th floor of Disque Hall (building 12) at 3141 Chestnut Street in Philadelphia. The machine is intact, and according to someone I asked, it powered up and worked fine when tested 3 months ago. The machine includes an enormous pile of backup tapes, both spool and cartridge type. (the MicroVax 3600 has the RA-82 and TK-70 drives needed to read both types of media installed) The machine is the size of a narrow but tall washing-machine, and probably weighs around 300 pounds. Bring a Van or Minivan with the seats taken out! Also, the closest parking spaces are on the other side of chestnut street, (the nice little lot in front of disque has a gate blocking entry), so a small equipment cart would be helpful too. (I may be able to borrow one from one of the labs, so contact me!) Also included is a large pile of Tape backups and spool backups from 1987 through 1991 at least, which *MIGHT* contain some previously-thought-lost VAX-related programs (maybe the lost source code to the final version of ROGUE, or the missing parts of early UNIX sourcecode, perhaps... though I'm really just dreaming there.) I'm hoping whoever takes the machine takes the tapes as well (and shares anything interesting on them) but just rescuing the machine from imminent doom would be a major boon. I would take the machine myself, but I don't have the means to transport it and I don't have the space to store it. According to someone I asked, the machine is scheduled for disposal sometime either later this week or next week, so get it QUICK! If you need assistance moving the machine or dealing with Drexel security, email me at jzg22 @t drexel d0t edu (@t = @, d0t = .) Jonathan Gevaryahu lord_nightmare @t users d0t sf d0t net jzg22 @t drexel d0t edu P.S. Al Kossow: I'm sorry I never got back to you in february about the votrax manual, my life's been pretty hectic over the last 6 months. I'll email you over the weekend.

18 years, 10 months

TG43 signal and the Nec 765

by dave04a＠dunfield.com

>> No, it for my ImageDisk utility, which is a replacement for >> TeleDisk with a documented image file format - I want to provide >> support for 8" drives that need TG43. > >What platforms does it work on? (I could certainly use something for >Linux which was able to do as much as possible with the crappy PC >FDC... :-) > >Presumably DOS-only? (Was there ever even a teledisk for Windows?) Yes, it runs under DOS. I need access to the "bare metal" without interference ... I don't think there was ever a TeleDisk for winblows, and I'm nut sure it would be feasable. Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Vintage computing equipment collector. http://www.parse.com/~ddunfield/museum/index.html

18 years, 10 months

TG43 signal and the Nec 765

by dave04a＠dunfield.com

>>Can you elaborate.? > >One of the things done when writing to a Floppy [it's done with all >FDC chips if it's done at all!] is to deliberately twook the bit >timing based on the bit pattern. >... >Hope this helps. I guess I should have been more clear - I understand Precomp, but I had the impression from your original message that some drives may expect special charactistics of the TG43 signals - I gather that "normal operation" (asserting it from Cylinder 44 on during writes) is all that is necessary? - let the drive worry about what to do, just provide the signal. >>No, it for my ImageDisk utility, which is a replacement for >>TeleDisk with a documented image file format - I want to provide >>support for 8" drives that need TG43. > >Ok, then I take it that this is in a PC FDC that is based on the >765 core? > >I ask as a way to point out that features and functions that the >base 765 chip have as implemented on an something like a Disk1A >are very differnt in a PC. Largely the PC design truncates the >interface from the 765 to something simpler abd often far less >flexible. Some of the really late chips (post 37C65) do not >even fully implement the full complment of interface signals >and may only have limited access to things like precomp timing >or worse those functions are "wired" by the chips designer to fit >their view of what floppies are (IE: antique = 8" floppy, >unsupported). Believe me, I am aware of the limitations of the PC design, and the rudeness of some of the later designs... fortunately a lot of the guys here have older machines :-) I'm creating a replacement for Teledisk because: - I need to reliably backup and restore diskette images, and to post them for download (along with the tools to recreate them). - Sydex no longer supports TeleDisk, and is actively trying to get it removed from availability. - TeleDisk does not document the image file format, which makes it very difficult to explore other means of recreating the image if TeleDisk doesn't succeed. I am also creating systems to backup and restore images of disks which are not compatible with the PC controller, including several systems which work by serial transfer with the original host. This is just another piece in the puzzle. Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Vintage computing equipment collector. http://www.parse.com/~ddunfield/museum/index.html

18 years, 10 months

Early Apple ][ board sells for $1K+

by vcf＠siconic.com

This was sold by the same guy that had the Apple-1 for sale (which he pulled today with no bids). http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5790352907 Off the scale as far as price goes (maybe $500 on the high end, $1,081 is excessive), but the listing has good photos showing what an early Apple ][ motherboard looks like, including the breadboarding area at the front. Does anyone know what the run count was on these first revision motherboards? -- 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 ]

18 years, 10 months

TG43 signal and the Nec 765

by ajp166＠bellatlantic.net

> >Subject: Re: TG43 signal and the Nec 765 > From: Dave Dunfield <dave04a at dunfield.com> > Date: Thu, 28 Jul 2005 08:40:38 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >>TG43 is mostly a relic signal of older 8" drives. Not all >>of them used it. Also it's supposed to be meaningless on read. >> >>I may add that more than a few designers also used demuxed TG43 >>to switch write precompensation in DD modes on 8" drives for >>better data reliability. > >Can you elaborate.? One of the things done when writing to a Floppy [it's done with all FDC chips if it's done at all!] is to deliberately twook the bit timing based on the bit pattern. The FDC provides a set of control signals (in hardware) and drives a bit of logic to intentionally smear the bits in time to allow for the media effects of close flux transistions. In most cses this is all hardware but usually the amount of precompensation is adjustable by both bit rate and a non FDC control register (back in the 1791/765 days). Some designs further modified the precomp value for the inner tracks (TG43) as drives didn't use TG43 or based on the deigners evaluation of bit crowding on the inner tracks might also alter the precomp timing to optimize flux transistion spacing. This is important as bits written to magnetic media tend to spread themselves out or crowd based on pattern when written closely. Hope this helps. >>Is this for a Cpro Disk-1(A) or something from the ground up? > >No, it for my ImageDisk utility, which is a replacement for >TeleDisk with a documented image file format - I want to provide >support for 8" drives that need TG43. Ok, then I take it that this is in a PC FDC that is based on the 765 core? I ask as a way to point out that features and functions that the base 765 chip have as implemented on an something like a Disk1A are very differnt in a PC. Largely the PC design truncates the interface from the 765 to something simpler abd often far less flexible. Some of the really late chips (post 37C65) do not even fully implement the full complment of interface signals and may only have limited access to things like precomp timing or worse those functions are "wired" by the chips designer to fit their view of what floppies are (IE: antique = 8" floppy, unsupported). Allison

18 years, 10 months

A minor Adventure in Vintage Computing

by hilpert＠cs.ubc.ca

So a friend and I headed out for a run today and on the way to the trails decided to take the shortcut across the lands of our friendly neighbourhood giant big-oil corp. oil refinery. This refinery was nearly 100 years old until it was mostly decommissioned and dismantled in the 1990s, although a portion of it still operates as a storage/transfer station for certain products. So after a little bushwacking and fence-hopping we were running down gravel roads between cement pads filled with weeds, cut-off steel stairways to nowhere, pipeline sections poking out of the ground and assorted other heavy-industrial detritus, while keeping an eye and ear out for the possible security-person-containing-vehicle to come bouncing over the hill. Off to one side of our route was one very old two/three story red-brick building that has yet to be demolished. This building looks like it could have been built in the 20s or 30s. We decided to take a peek. The big two-storey service door was open to the skies, but the building was still filled with equipment: giant motor/pump sets, engines/generators, steel walkways, pipes everywhere, peeling paint, all dead and quiet, just pigeons in the rafters and the occasional whoooosh from some pressure vent outside to spook us. My friend and I went upstairs into a room with the floor and shelves littered with crates, small motors, bits of equipment, cabling, etc. On one wall was a green & black, full-height, double-wide equipment cabinet, one door half open and large circuit boards visible in a rack. My brain started to tweek. In the mid-70s, as a high-school student, I and a few other students had a visit to the refinery one day to be shown the computer system that ran the refining operation. About the only thing I remember from that day is that it was a Foxboro real-time process-control computer that had been installed some years earlier. I had figured it was now long gone from when the refinery was decommissioned and the newer buildings, where the computer was likely to be located, were demolished. But there's not a lot of reason other than a computer system for circuit boards that large to be hanging around an oil refinery. Sure enough, the cabinet had a little "FOXBORO" logo up in one corner. Looking around a little more turned up a very large floor-standing video console with "FOX-1" in addition to the "FOXBORO" logo on it, a GE termi-net printer/terminal, and a sub-room packed with racks of what appear to be the I/O interface/drive equipment (where all the wires from the sensor/control points around the refinery terminate and are interfaced to the processor). Pulling a couple of the circuit boards from the main cabinet suggests the processor is TTL-based, although there were date codes from the early 80s so it may have been upgraded from the 70s. The console was quite cool, I speculate >from it's size and complexity it may have been an early graphics console that displayed process equipment/flow diagrams; date codes on ICs in it were still early 70s. Didn't see any disc or mass-storage device or even paper-tape I/O. Considering it's real-time application perhaps it functioned without a disk, just booted the whole system (from what?) at startup and survived in RAM. I don't know a lot about Foxboro, I believe they were a spin-off or startup company in the 60s that were early entrants into the (then small and state-of-the-art) area of computer-based real-time process-control for large industrial plants. They are one of those names you don't run across much unless you run in those circles. Additional comments about Foxboro and their systems from those who may know more appreciated. My friend finally dragged me out and we continued on our run into the forest with a little dip in the lake on the way home.

18 years, 10 months

TG43 signal and the Nec 765

by dave04a＠dunfield.com

>TG43 is mostly a relic signal of older 8" drives. Not all >of them used it. Also it's supposed to be meaningless on read. > >I may add that more than a few designers also used demuxed TG43 >to switch write precompensation in DD modes on 8" drives for >better data reliability. Can you elaborate.? >Is this for a Cpro Disk-1(A) or something from the ground up? No, it for my ImageDisk utility, which is a replacement for TeleDisk with a documented image file format - I want to provide support for 8" drives that need TG43. Regards, Dave PS: For those on my list - I'm making some last minute changes so I won't be sending the update until this evening. -- 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

18 years, 10 months

TG43 signal and the Nec 765

by ajp166＠bellatlantic.net

> >Subject: TG43 signal and the Nec 765 > From: Dave Dunfield <dave04a at dunfield.com> > Date: Thu, 28 Jul 2005 06:32:58 -0400 > To: cctalk at classiccmp.org > >Hi Guys, > >I'm using a relatively modern 1/2 height 8" drive for my PC >interface, which does not seem to care about TG43 - I left >it unconnected, and it appears to be writing images just fine. > >It would however seem to be a good idea to support it for >older drives and drives that need it... > >Question: > >According to the NEC 765 datasheets, pin 38 is LC/DIR, it >indicates "Low Current" (TG43) during writes to inner tracks, >and "direction" during STEP operations. > >It would seem that you might be able to simply stuff this >signal into both pins 34 (Direction) and 2 (TG43) of the 8" >interface, since the drive should not care about DIRECTION >when STEP is not active, and it should not care about TG43 >when WRITE is not active, and the two operations are mutually >exclusive. However none of the information and cable diagrams >I've seen indicate such a connection, suggesting that this >might not work. Some drives don't like that. > >Q: Can you simply drive both signals from the one source, or > do TG43 and STEP need to be externally demultiplexed? > The standard has to bee demultiplex it. The need and use of TG43 is for writing. >As an alternative, I think I will also provide an option to >generate TG43 via a parallel port output. > >Q: Should TG43 be asserted any time the drive is positioned > to a cylinder >43, or should it be asserted only during > WRITE operations when at a cylinder >43? TG43 is mostly a relic signal of older 8" drives. Not all of them used it. Also it's supposed to be meaningless on read. I may add that more than a few designers also used demuxed TG43 to switch write precompensation in DD modes on 8" drives for better data reliability. Is this for a Cpro Disk-1(A) or something from the ground up? Allison

18 years, 10 months

TG43 signal and the Nec 765

by dave04a＠dunfield.com

Hi Guys, I'm using a relatively modern 1/2 height 8" drive for my PC interface, which does not seem to care about TG43 - I left it unconnected, and it appears to be writing images just fine. It would however seem to be a good idea to support it for older drives and drives that need it... Question: According to the NEC 765 datasheets, pin 38 is LC/DIR, it indicates "Low Current" (TG43) during writes to inner tracks, and "direction" during STEP operations. It would seem that you might be able to simply stuff this signal into both pins 34 (Direction) and 2 (TG43) of the 8" interface, since the drive should not care about DIRECTION when STEP is not active, and it should not care about TG43 when WRITE is not active, and the two operations are mutually exclusive. However none of the information and cable diagrams I've seen indicate such a connection, suggesting that this might not work. Q: Can you simply drive both signals from the one source, or do TG43 and STEP need to be externally demultiplexed? As an alternative, I think I will also provide an option to generate TG43 via a parallel port output. Q: Should TG43 be asserted any time the drive is positioned to a cylinder >43, or should it be asserted only during WRITE operations when at a cylinder >43? 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

18 years, 10 months

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test-drb July 2005