test-drb January 1999

test-drb@ccmp.vtda.org

189 participants
897 discussions

Reiability of wrong media (was: is out of 5-1/4" diskettes

by pete＠dunnington.u-net.com

On Jan 21, 15:15, Don Maslin wrote: > Subject: Re: Reiability of wrong media (was: is out of 5-1/4" diskettes > On Thu, 21 Jan 1999, Tony Duell wrote: > > Don't forget that '720K' 5.25" disks also exist, although they're not > > common on IBM PCs. By that I mean 80 track, double density, double sided, > > 300 oersted coercivity. Most of those do not have the reinforcing ring IIRC. And they're pretty common on non-MSDOS systems. I far more 80-track DS drives than 40-track of any flavour. > > > 720K 5.25" v 360K 5.25": again, an issue of testing/certification, > > > similar to SS v DS. At least for a while, they were manufactured the same, > > > but were tested/certified for 48tpi or 96 tpi. > > > > I have had very little success in formatting 48tpi disks in 96tpi drives. > > As I mentioned earlier, this includes name-brands like 3M.. > > Interesting! I have never had a problem using even generic 48tpi disks > at 96tpi. > - don Nor have I, usually. I tend to treat all double-density 5.25" disks the same. Some of the old ones I have were converted to be "flippy" 40-track, and some time ago I found one such without a label. Not knowing whether it really had been formatted flipped, I tried it out, using the by-now-standard 80-track DS drive and a two-step circuit, and found it had. "OK, so that's a flippy", I said to myself. A little later, I re-read the catalogue -- and got a different listing! I had inadvertantly catalogued side two, with the disk right-side-up -- and realised that the tracks must not line up, so side two had two sets of data, going in opposite rotations, with the tracks interleaved! So I have a three-sided 40 track disk :-) > > > 3", 3.25": Many newbies will get sloppy in reference to 3.5" diskettes, > > > without realizing that there actually were 3" and 3.25" diskettes. 3" > > > were used by Amstradt, some non-US Canon?, and Amdek add-on drives for Coco There are also 2.5" disks, though the only ones I've seen were made by TDK for an early digital camera. Anyone remember the make? Canon? -- Pete Peter Turnbull Dept. of Computer Science University of York

27 years

Reiability of wrong media (was: is out of 5-1/4" diskettes

by roblwill＠usaor.net

Every computer that I've ever owned, When it does a memory test of "1 megabyte", the listing is always 1024KB......OK. -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1> -----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Friday, January 22, 1999 2:58 PM Subject: Re: Reiability of wrong media (was: is out of 5-1/4" diskettes >> Find me an authoritative reference that defines a megabyte as 1024 * 1024 >> bytes and I'll eat a pancake. > >I don't know how 'authoritative' you need, but will an IBM TechRef do? > >The PC/AT one that I've just picked up says : > > >M (1) Prefix mega; 1,000,000. (2) When refering to computer storage >capacity, 1,048,576 (1,048,576= 2 to the 20th power) > >Also >Mb 1,048,576 bytes. > >Incidentaly, it also defines > >Gb 1,073,741,824 bytes (=2^30 ARD) > >Can you find a reference (other than an advert :-)) that defines it any >other way? > >Anyway, I might accept that 1Mbyte = 10^6 bytes, particularly if you >happen to have a decimal or BCD machine :-) (this is classiccmp). But I >don't see any justification for making it 1024000 bytes. And that's the >only way you can have '1.44Mbytes' on a HD 3.5" disk > >-tony > >

27 years

C-10 Certified leaderless cassettes

by dogas＠leading.net

I cleaned out the local Radio Shack Liquidation Center of all their computer cassettes. At a nice price of 12cents each I bagged well over a hundred... So, if anyone is really ruffing it and could use some ust let me know. - Mike: dogas(a)leading.net

27 years

Bubble Memeory was Re: eBay Finds (was: Ebay Posts was...)

by allisonp＠world.std.com

<I can't get to the bubble memory chip because it has a metal shield <spot-welded around it. Wrapped around 4 of the 6 sides, so to speak. I'= <ve tried removing this sort of thing before - nigh impossible without a <chisel, and I'm not about to do that. <Chip has 12 pins/side, for a total of 24, if that helps. Peeling the shield would destroy the part. It holds in place the magnets used for fixed bias to maintaining the bubbles during power off. There is nothing much to see under it. Allison

27 years

manuals, mac software

by lemay＠cs.umn.edu

Well, all this talk of supplies of old floppies got me to worrying a bit, so I obtained permission to grab a bunch of old manuals and floppy disks from work. Actually I'm rather annoyed, because a former employee came back and asked for the N-Cube computer, and was given permission to take it! Thats a multi-processor machine with hypercube data exchange links between processors.. Sigh.. and it looked kool too (we had christmas lights blinking inside its smokey front panel, and students would see it and be very impressed at all the computing that was being done!) Anyways, I grabbed a bunch of old disk drive manuals and disk drive controller manuals, from abnout the sun2/sun3 era. Rimfire controller manuals for SMD-E style drives, eagle (maybe double eagle) drive manuals, CDC Sabre drive manuals, Fujitsu drive manuals (i think these are probably 5.25" drives, but they were rackmounted in teh old days and were in very long cases). If there is any interest i can catalog all the names of this stuff. I also have a set of NeXT manuals. Might be version 1.0, might be 2.1 And I'll be grabbing approximately 800 3.5" DSDD floppy disks that currently have very old MacIntosh software on them. Mainly stuff like Word, Excel, etc.. If anyones interested in this, I can work on making a detailed list of the manuals or software. Perhaps I could trade the manuals for something interesting. -Lawrence LeMay

27 years

OT: Alien Media (was Disasters and Recovery)

by pete＠dunnington.u-net.com

On Jan 22, 12:57, Max Eskin wrote: > Subject: Re: OT: Alien Media (was Disasters and Recovery) > Philip.Belben(a)pgen.com wrote: > > Metre, Kilogram, Second, Ampere, Kelvin, Mole and Candela (normally > > Kilogram? Why not gram? The whole system is based on units that are matched to each other in such a way that the constants involved in relating units to other units work out to unity. So the kilogram just happens to be a handier quantity than a gram, and saves a lot of dividing or multiplying by 1000. Except, of course, in real life, where units are rarely handy sizes at all :-) On Jan 22, 13:28, Cameron Kaiser wrote: > Subject: Re: OT: Alien Media (was Disasters and Recovery) > :: Uh, I thought a gram was defined as 1 cc of water at 4C. A kilogram is > ::1,000 cc of water at 4C, which is one litre of water (a litre being 1,000 cc > ::volume). > > The original kilo is a big lump of metal in a bell jar, when the kilogram > was introduced as a standard. It was originally intended to be a cubic decimetre of water at it's maximum density. Unfortunatley, that turned out to be 28 ppm to large -- the constants I mentioned above don't quite work out to unity. So it was changed to an arbitrary amount to suit -- and the litre was defined as the volume of water that had that mass at it's maximum density. Hence a litre was actually 1000.028 cm^3. Since that just moves the "obviously silly" constant to a different place in the scheme, it was redefined later to be exactly 1000 cm^3, but with the recommendation that it not be used for work of high accuracy. Hmmm.... and we thought IBM were having trouble with the megamaths. -- Pete Peter Turnbull Dept. of Computer Science University of York

27 years

PC's Limited

by bill＠chipware.com

On Thu, 21 Jan 1999, Uncle Roger wrote: > I will break with my above comments long enough to say that if I had lots > of storage space, it would be really cool to get a PC's Limited pc... My roommate in college had their 12MHz 286 with 640K of *STATIC* RAM. Oh man... I would have given my right arm for that machine. The front panel was really useful, not just that clone fake display set with jumpers. It showed POST codes, disk access info CPU speed... That was a cool machine. Bill Sudbrink

27 years

The "megabyte" discussion

by SUPRDAVE＠aol.com

In a message dated 1/22/99 3:03:37 PM EST, dastar(a)ncal.verio.com writes in repsonse to chuck mcmannis: > > I bought an IBM Deskstar hard disk that was rated at 810 Megabytes and it > > had a note inserted into the packaging that had, IIRC, this to say about > it: > > > > Dear Customer, > > The disk you have purchased holds 810,549,248 bytes when it > > is formatted. Some programs will use the value of 1,048,576 bytes > > as the size of a megabyte and will show this disk as having only > > 773 "megabytes" of storage, other programs will use 1,024,000 bytes > > as the size of a megabyte and show the disk as having 791 or 792 > > megabytes. We don't understand it either, sorry for the confusion. > > IBM Support > > I can hardly believe IBM would put that last sentence in any of their > literature. Some jocular IBMers must've slipped that thru when the > corporate exec wasn't looking. > well, you better believe that induhviduals can and do escalate up to corporate about things like this that they cannot or will not understand. hey, a little humour always helps the rank novice to get a clue. david

27 years

OT: Alien Media (was Disasters and Recovery)

by Philip.Belben＠pgen.com

>> extremes, things like the definition of a volt may be needed... > > :-)... Possibly.. I think that might be going a bit far. I would hope > some other electrical books had survived. > > If not, how would you define a 'volt'? In terms of the steps on a > microwave-excited Josephson Junction? It's reproducable, and > frequency/time is also easy to define. I was thinking of defining it in terms of a bandgap, such as used in precision reference "diodes". I'd like to define it in terms of SI units, but the Kilogram is not too easy (yet). Philip.

27 years

FYI: MEI/Microcenter is out of 5-1/4" diskettes

by rcini＠msn.com

Hello, all: I tried ordering the bulk 5-1/4" disks yesterday. Gone for good...none left...sorry...bye bye...look elsewhere. Better start stockpiling 360k diskettes... [ Rich Cini/WUGNET [ ClubWin!/CW7 [ MCP Windows 95/Windows Networking [ Collector of "classic" computers [ http://highgate.comm.sfu.ca/~rcini/classiccmp/ [ http://highgate.comm.sfu.ca/~rcini/pdp11/ <================ reply separator =================>

27 years

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test-drb January 1999