test-drb July 2007

test-drb@ccmp.vtda.org

189 participants
323 discussions

by hamren＠sdu.se

The first computer built by Computer Automation, circa 1967, was the PDC 808. It was an 8-bit TTL-only machine with a very basic instruction set. In "Computer Technician's Handbook" Brice Ward describes tat machine in great detail. Should be enough to build a replica from. A scanned version of the relevant parts of that book is available from http://www.sdu.se/computer-automation-museum/books_in_the_collection.html PDC stands for Programmable Digital Controller. The word "computer" was avoided because people were afraid of them! The "8" means 8 uS cycle time, and "08" means 8 bits. The 208 was three times as fast (2.66 uS cycle time, hence the "2"). /Lars ------------------------------------------------------------------- Lars Hamr?n Tel...: +46( 46)189090 Svensk Datorutveckling Mobile: +46(705)189090 Vadm?llan 211 e-mail: hamren at sdu.se S-225 94 Lund WWW...: www.sdu.se Sweden

18 years

Northstar hard sector floppy disks with Catweasel

by ajp166＠bellatlantic.net

> >Subject: Northstar hard sector floppy disks with Catweasel > From: "Andrew Lynch" <lynchaj at yahoo.com> > Date: Sun, 08 Jul 2007 12:10:35 -0400 > To: <cctech at classiccmp.org> > >Hi, > >Has anyone had success reading Northstar hard sector floppy disks with the >Catweasel? I keep hearing about this Catweasel board and I've never read of anyone successfully using one. My be if it works there may be nothing to tell. NS* floppies are a simple affair. The logic needed to read them is trivial and the data rate is 15625(SD) or 31250(DD) bytes/second. The NS* board logic is clock recovery, shift register and a 8wide NAND to detect if the pattern in register is a sync byte. The basic read is, wait for sector hole (hard sector has both an index hole and a data sector hole and a oneshot is used to tell which is which. Once the desired sector hole is found wait for sync (FBh). When sync is found read bytes as they are data(256 sd or 512 dd) the next byte is a check char if the check matches data in ram check byte you have a sector. There are no bytes for sector address or other info as hard sectoring us used to track that. In 8080 code ignoring the head step and all the other housekeeping the read sector code is less than 50 bytes. You can find that code on the net (NS* BOOT ROM). Because of it's simplicity I'm surprized no one has implemented a PC parallel port interface that is a subset of the NS* MDS sans boot roms and bus interface as the data rates are not out of the realm of what a 386 class or faster PC can transfer from a printer port. Manual and prints for the S100 card are available on line and the manual has low level programming information as well. There are no mysteries either hardware or software and the design is dirt simple. Actual parts count for the MDS=A (SD version ) is 47 peices TTL and if you take out boot proms (2 256x4 74287) and board select prom (1 256x4 74287) and the parts needed to talk to the S100 bus your under 40pieces of TTL the most complex of which is 74161 (4 bit counter). I'd add the SD version does not have any analog (opamps) or RC oneshots though the DD version does. the basic timing of the board is a long string of counters synced to the index hole to provide sector position (R/W) and byte timing for (W) and motor time out. No state machines or anything fancy. Allison > > > >Thanks! > >Andrew Lynch

18 years

TTL homebrew CPUs

by ajp166＠bellatlantic.net

> >Subject: Re: TTL homebrew CPUs > From: woodelf <bfranchuk at jetnet.ab.ca> > Date: Sat, 07 Jul 2007 19:58:10 -0600 > To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> > >Dave McGuire wrote: >> >> Ahh, back in the days in which BYTE was a technical magazine. Do you >> have any recollection of when that article was printed? I'd love to >> find it. > >So would I. I suspect 90% of BYTE magizines from local ( ie small) >libraries have been tossed out. It has been tossed out here. >I am not sure if the 32 bit machine >even made it microfilm copies of byte. But I do know it was some time >after BYTE became a PC mag. It was in two parts - part 1 software? >part 2 hardware. > September and October 1985, it was 16bit. EGO 1 wa s it's name. I ahve both copies and a few others regarding TOY a 16bit minimal computer for teaching. I believe issues of byte made it to microfilm and possibly even to compendiums on CDrom. Allison

18 years

TTL homebrew CPUs

by ajp166＠bellatlantic.net

> >Subject: Re: TTL homebrew CPUs > From: "Chuck Guzis" <cclist at sydex.com> > Date: Sat, 07 Jul 2007 13:16:48 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 7 Jul 2007 at 21:38, Lars Hamren wrote: > >> The first computer built by Computer Automation, circa 1967, was the >> PDC 808. It was an 8-bit TTL-only machine with a very basic >> instruction set. In "Computer Technician's Handbook" Brice Ward >> describes tat machine in great detail. Should be enough to build a >> replica from. > >Wasn't there an article in one of the magazines (Byte, >Microcomputing, Kilobaud???) where a fellow gave details about >constructing his own TTL 8080 CPU? Check Mick and Brick on Bit slice design and implmentation of an 8080 in bitslice. Actually 8080 is easier if you are not trying to create a peice of hardware that results in a 40pin plug to replace an 8080. By that I mean something that would run 8080 programs but not electrically compatable and may be slightly different timing. There was also a 16bit CPU in Byte, plus there were articles on TOY (minimalst machine) and further articles on microprogrammed vs hard wired logic. The 16 bitter was EGO in the September 1985 issue (part 1, Part2 is October '85). So there is another fairly simple machine of very buildable proportions with a better than most instruction set. Allison > >Cheers, >Chuck

18 years

Multiple Servers & spares in WA (Kent), FREE to non-profit org!

by kyrrin＠bluefeathertech.com

Classiccmp folk, Time to "flow through" more of my older gear! I have available three Compaq Proliant series servers of various models and speeds, none slower than 400MHz. These were all retired from my network, so I know they're functional. They've simply been replaced by upgraded systems. They all still have RAM (none less than 512MB), and I also have some spare power supplies. I may even be able to scare up enough four-gig disks to make an array. THE KICKERS... LOCAL PICKUP ONLY -- SHIPPING IS NOT AVAILABLE! I simply do not have the facilities or time to ship equipment of this nature. Pickup location is in Kent, Washington, southeast of Seattle. You may reach me at (253) 639-2996. I will donate all three servers, plus spares, FREE to any 501(c)(3) non-profit, or similar organization that can give me a tax-deduction receipt. Failing that, I think $50 per unit is a fair price. Again, I must emphasize -- LOCAL PICKUP ONLY! Shipping is NOT available for this equipment. No, I will not "part them out." These are usable systems, and I want to keep them that way. Thanks much. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"

18 years

DEC Boot ROMs claimed

by kyrrin＠bluefeathertech.com

The boot ROMs have been claimed. My thanks to James Markevitch, and to the list members. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"

18 years

Available for Postage: DEC Boot ROMs

by kyrrin＠bluefeathertech.com

CCTech folk, I have available, for the cost of postage, a pair of DEC boot ROMs used with the M9312. They are the 23-755A9 and 758A9 devices. Additional notations I got with them indicate that they were used with Spectra Logic controllers. The 755 is, apparently, for booting DPn or DBn disks, while the 758 is for booting MTn devices. First respondent gets 'em. Thanks much. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner & Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"

18 years

trace wrinkles

by marvin＠west.net

"Wrinkles" is a rather vague description :). When using soldermask and wave soldering the board, the soldermask itself will wrinkle and I would guess all of us who have worked on boards have seen that one. Since a large board can pick up a fair amount of solder during wave soldering (depending on geometry), this adds useless cost to the assembly of PCBs. That problem was eliminated by going to soldermask over bare copper. The second cause of "wrinkles" (and this is probably what you are referring to) is due to the cooling characteristics of the solder after reflow, and this is usually far more prominent on larger circuit areas. I would not classify these as wrinkles per se, but rather the visual boundries where the solder started to solidify on different parts of the circuit. > From: David Griffith <dgriffi at cs.csubak.edu> > > I haven't heard anyone discuss this yet: what causes traces on some old > PCBs to wrinkle and not others? My guess is a combination of suboptimal > glue and wide temperature swings.

18 years

7 RK07 packs in UK

by rescue＠hawkmountain.net

Saw these while searching eBay for other things and thought I'd pass this along in case anyone is looking for RK07 packs... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120133419517 I have no knowledge of the seller (or even RK07s :-) )... -- Curt

18 years

Server hosting on a budget - use legacy kit

by lproven＠gmail.com

http://www.channelregister.co.uk/2007/07/07/ebuyer_runs_site_on_commodore64/ I /like/ this. There's a site admin with a sense of humour there somewhere... -- Liam Proven ? Blog, homepage &c: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419 AOL/AIM/iChat: liamproven at aol.com ? MSN/Messenger: lproven at hotmail.com Yahoo: liamproven at yahoo.co.uk ? Skype: liamproven ? ICQ: 73187508

18 years

← Newer
1
...
21
22
23
24
25
26
27
...
33
Older →

Jump to page:

2025

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 2007