test-drb May 2006

test-drb@ccmp.vtda.org

195 participants
346 discussions

by julesrichardsonuk＠yahoo.co.uk

Question on a local newsgroup about PC power supplies and whether the -5V rail is used any more, and it's prompted me to wonder what it was *ever* used for? Did the original IBM PC make use of -5V for any reason? Or is its inclusion maybe a hang-up from earlier machines that used three-rail memory devices? Far as I know, things that needed -ve rails (like soundcards, serial ports etc.) all used -12V... curious. cheers Jules

18 years, 7 months

Olivetti M20

by pete＠dunnington.plus.com

On May 18 2006, 7:13, dwight elvey wrote: > It definitely doesn't like stepping at around 2 to 2.5 ms someplace. > I send the value 8 to the controller that is suppose to be 4.0 ms and > that works fine. > I don't know how a buffered seek would work on a MFM drive? > Are you saying that it should take in what ever step pulses I send it > and step at 8ms, regardless of what I send. Not quite, what Chuck means is that most MFM drives after the ST506 have a slightly different interface, and should buffer the step pulses, and internally it will ramp up the step rate and ramp down again -- it can step faster once it gets going, than it can if it comes to a stop between pulses. This style of interface is often called an ST412 interface instead of ST506, because the ST412 was the first drive that supported it. Below is part of the Seagate data sheet for the ST251. You'll see the first line identifies it as an ST412-type interface rather than ST506. You can also see it can accept step pulses at quite short intervalsi, and should buffer them. If you give it a single pulse it will take 8ms to move one track, but if you feed it a series of pulses it should ramp its step rate up (and down when it's close to the destination cylinder) so that it can step the whole width of the disk in only 70ms. ST-251 ST412 MFM [ connector diagram goes here ] UNFORMATTED CAPACITY (MB) ________________51.2 FORMATTED CAPACITY (17 SECTORS) (MB) _____42.8 ACTUATOR TYPE ____________________________STEPPER TRACKS ___________________________________4,920 CYLINDERS ________________________________820 HEADS ____________________________________6 DISCS ____________________________________3 MEDIA TYPE _______________________________THIN FILM RECORDING METHOD _________________________MFM TRANSFER RATE (mbits/sec) ________________5.0 SPINDLE SPEED (RPM) ______________________3,600 AVERAGE LATENCY (mSEC) ___________________8.3 INTERFACE ________________________________ST412 SECTORS PER DRIVE ________________________83,640 TPI (TRACKS PER INCH) ____________________777 BPI (BITS PER INCH) ______________________9,935 AVERAGE ACCESS (ms) ______________________40/28* SINGLE TRACK SEEK (ms) ___________________8 MAX FULL SEEK (ms) _______________________ /70 MTBF (power-on hours) ____________________100,000 POWER REQUIREMENTS: +12V START-UP (amps) _2.0/2.5* +12V TYPICAL (amps) __0.5 +5V TYPICAL (amps) ___1.0/1.2* TYPICAL (watts) ______11/12* MAXIMUM (watts) ______29/36* BUFFERED STEP PULSE RATE (micro sec) _____3-200 WRITE PRECOMP (cyl) ______________________N/A (821) REDUCED WRITE CURRENT (cyl) ______________N/A (821) LANDING ZONE (cyl)________________________AUTO PARK IBM AT DRIVE TYPE ________________________44, 40, or 3** -- Pete Peter Turnbull Network Manager University of York

18 years, 7 months

hp 264x terms on ebay

by kossow＠computerhistory.org

> The guy emailed me and is ready to talk about a volume purchase deal now. Has anyone actually RECEIVED one of that they bought from him? I probably was one of the first to buy one, and it ain't here yet.

18 years, 7 months

Need help with large mini-computer near Jacksonville, FL

by sellam＠vintagetech.com

I've acquired a largish mini-computer near Jacksonville, Florida, and need help moving it. I plan to ship it to California via freight, and am hoping to make the trip out to Florida so I can pack it myself, but in the meantime I may have to get it moved from its current location to somewhere nearby. Is anyone near Jacksonville that can help me with this? A pickup truck and a couple sets of strong hands is all that's required to move them. They take up roughly 30 sqft of floor space (each unit is no more than 3x3 feet from what I can tell). I may even just go ahead and rent a small storage locker until I can get out there to prep the machines for shipping. Any help will be appreciated and rewarded with some goodies. Please reply to me directly <sellam at vintagetech.com>. Thanks! -- 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, 7 months

hp 264x terms on ebay

by jwest＠classiccmp.org

The guy emailed me and is ready to talk about a volume purchase deal now. Apparently sales tapered off ;) I will be emailing everyone who emailed me off-list to confirm... Jay

18 years, 7 months

IBM system 34 to be melted down in Kentucky, if you let it...

by tosteve＠yahoo.com

I received this email. Respond to Robin if interested. " I have two old IBM System 34 computers that I am interested in selling or recovering the gold from them. Anyone interested in purchasing please contact or if you have information on recovering the gold please contact. Thank you. Robin Archer, Louisville Kentucky Robin_archer at bellsouth.net " __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

18 years, 7 months

EOL for Intel 186, 386, 486 and i960

by r_a_feldman＠hotmail.com

The Register reports that Intel is discontinuing the 186, 386, 486, and i960 processor lines, with EOL next year. More information at http://developer.intel.com/design/pcn/Chipsets/PCN106013.pdf. Bob

18 years, 7 months

Push button under the power cord cover on a VAX4000

by jplist＠kiwigeek.com

Hey folks; My recently acquired VAX has started acting up, seems it doesn't always like to power on. When I hit the main switch, the PSU light comes on (orange, by the switch) but the DC OK light does not come on, nor does the chassis power up. I've found that to get the PSU fully powered up I have to turn it off, and push that momentary switch button under the power socket on the PSU. On the VAX there's a sliding cover thing, which when down allows you to plug in the power cord. When you slide it up, it covers the power socket, but allows you access to the thumbscrew which holds the PSU in. When you lift this cover up to gain access to this screw, the cover pushes on some little button under there. What on earth does this button do, and why is it my VAX won't power on until I hit it? :P My thanks all; JP

18 years, 7 months

OT: Software for Transtronics/Intronics EPROM programmer

by robert.yount＠totalfiregroup.com

Did you get the Intronics Pocket programmer software? I have it. Robert Yount Senior Engineer Morning Pride Mfg. IR Camera Lab

18 years, 7 months

Phillips GPIB cable

by aw288＠osfn.org

I have a 2 meter (or so) GPIB cable with a PM 9483/51 adapter, for use with that old Phillips logic analyzer. Anyone need this, ultra cheap? If not, in the scrap it goes. William Donzelli aw288 at osfn.org

18 years, 7 months

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test-drb May 2006