fzsitvay@techbook.com (Frank Zsitvay) (12/12/90)
well, after a little experimentation, it seems that uniform DOES know how to massage an AT disk controller (HD) to produce 8 inch disk formats. however, i do not know if the formats it produces are readable on 8 inch machines. all i did was install my dsqd 5.25 inch drive as an 8 inch dsdd drive, and try the 8 inch formats. it does format the 5.25 inch drive as either 77 or 154 tracks (depending on single or double sided formats) and it can read its own formats. now, to find out for sure if you can use an AT floppy port, I (or someone who has a spare floppy) will have to wire up an 8 inch drive to the 5.25 inch controller and see if it really does work. i had a file around here that showed how to wire a HD drive to an 8 inch port, and imagine that i'll have to use the same cable for the 8 inch drive to 5.25 inch controller. problem is, it's buried in a couple boxes of 8 inch cp/m disks and i don't relish the thought of spelunking into that box to find it. besides, since there are probably other people on the net that want this information, could someone be so kind as to post that file for us?? also, if anyone has any comments or suggestions concerning making a cable for this, feel free to add to the discussion. i'm going to have to visit the library sometime later in the week and see what signals on the interface will have to go where, and work from that, but if someone knows it off of the top of their head, it would save me a trip into downtown portland, something i also do not relish. and lastly, if someone does try this and get it working, please let everyone else know of your success, and perhaps even post some tips on getting it all to work. but it looks like the hard part is over. uniform does know how to work a HD controller. -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!
jm59@prism.gatech.EDU (MILLS,JOHN M.) (12/13/90)
I have an SD-Systems setup, using their Versafloppy III (?) from back
before the flood. This controller has a connector for 5 in. drives,
but I've been unsuccessful getting it to run an AT-style (dshd) drive.
Any suggestions welcome: is the connector the same for the hd drive as
for the dsdd model? Termination of cable req'd? Jumpers somewhere?
Symptoms are that my FORMAT selects the drive and steps across it
(trying various formats originally intended for 5 in. drives), then
doesn't find the format when I look for the directory, use STAT, or
run DTYPE (a drive checking utility which looks at formats). Any
suggestions welcome. BTW, the card set originally came from JADE.
It has worked impeccably, except I had apparently a defective mapping
PROM, for which JADE sold me a replacement. Thanks. :=).
--
MILLS,JOHN M.
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!jm59
Internet: jm59@prism.gatech.edugrege@gold.gvg.tek.com (Greg Ebert) (12/14/90)
The 1.2M floppy format uses the same data-transfer rate as an 8" drive (500Kbits/sec). This is also true for 1.44M drives. 360K floppies use the standard 250Kbits/sec. All IBM formats use MFM (Double-density). CP/M uses FM (single density), and MFM.
berger@iboga (Mike Berger) (12/14/90)
I have hooked up 8" drives to standard XT floppy disk controllers with some slight additional circuitry. I was able to use the Maynard FDC drivers in Uniform. I am not sure whether the additional hardware is necessary for an AT disk controller. -- Mike Berger Department of Statistics, University of Illinois AT&TNET 217-244-6067 Internet berger@atropa.stat.uiuc.edu
donm@pnet07.cts.com (Don Maslin) (12/14/90)
fzsitvay@techbook.com (Frank Zsitvay) writes: > >i had a file around here that showed how to wire a HD drive to an >8 inch port, and imagine that i'll have to use the same cable >for the 8 inch drive to 5.25 inch controller. problem is, it's >buried in a couple boxes of 8 inch cp/m disks and i don't relish >the thought of spelunking into that box to find it. besides, since >there are probably other people on the net that want this information, >could someone be so kind as to post that file for us?? > >also, if anyone has any comments or suggestions concerning making a >cable for this, feel free to add to the discussion. i'm going to >have to visit the library sometime later in the week and see what >signals on the interface will have to go where, and work from that, >but if someone knows it off of the top of their head, it would >save me a trip into downtown portland, something i also do not >relish. > The following table is extracted from the CompatiCard manual: Card 34 50 8 Inch Drive Signal Name Pin Direction Pin Signal Name ======================================================================== Programmable 2 ---> 2 Low Current Index 8 <--- 20 Index Drive Select 1/3 12 ---> 28 Head Load Motor Enable 1/3 16 ---> 18 Drive Select 2 Step Direction 18 ---> 34 Direction Select Step Pulse 20 ---> 36 Step Write Data 22 ---> 38 Write Data Write Enable 24 ---> 40 Write Gate Track 0 26 <--- 42 Track 0 Write Protect 28 <--- 44 Write Protect Read Data 30 <--- 46 Read Data Select Head 1 32 ---> 14 Side Select Connect odd number pins of 34 pin connector to odds of 50 pin connector Hope this helps................................... - don Keeper of the CP/M System Disk | UUCP: {nosc ucsd crash ncr-sd}!pnet07!donm Archives for the Dino(saur)SIG | ARPA: simasd!pnet07!donm@nosc.mil - San Diego Computer Society - | INET: donm@pnet07.cts.com
sprague.wbst311@XEROX.COM (12/15/90)
> The 1.2M floppy format uses the same data-transfer rate as an 8" drive > (500Kbits/sec). This is also true for 1.44M drives. > 360K floppies use the standard 250Kbits/sec. Hmmm, I knew both of those, but what is the transfer rate for a quad density drive? I assume 250K bits/sec? ~ Mike
fzsitvay@techbook.com (Frank Zsitvay) (12/16/90)
In article <1990Dec13.220504.25302@simasd.uucp> donm@pnet07.cts.com (Don Maslin) writes: [8 inch to 5.25 inch signal table deleted in the interest of space] >Hope this helps................................... - don it sure does... thanks a bunch... -- fzsitvay@techbook.COM - but don't quote me on that.... American Oil Company motto - Bend over, We'll pump!!!
ianj@ijpc.UUCP (Ian Justman) (12/16/90)
sprague.wbst311@XEROX.COM writes: > > > The 1.2M floppy format uses the same data-transfer rate as an 8" drive > > (500Kbits/sec). This is also true for 1.44M drives. > > > 360K floppies use the standard 250Kbits/sec. > > Hmmm, I knew both of those, but what is the transfer rate for a quad density > drive? I assume 250K bits/sec? What do you mean by "quad"? I've heard it used several different ways. Quad meaning either the high density disks (1200k), or the DD 96tpi. If you're talking about the latter, it should be the same rate as DSDD, 48tpi.
bill@bilver.uucp (Bill Vermillion) (12/17/90)
In article <"14-Dec-90.22:31:53.EST".*.Michael_D._Sprague.wbst311@Xerox.com> sprague.wbst311@xerox.com writes: > >> The 1.2M floppy format uses the same data-transfer rate as an 8" drive >> (500Kbits/sec). This is also true for 1.44M drives. > >> 360K floppies use the standard 250Kbits/sec. > >Hmmm, I knew both of those, but what is the transfer rate for a quad density >drive? I assume 250K bits/sec? > "Quad density" is a mis-nomer. It started many many years ago when someone (I think it was Micropolis) was able to reduce the step positions reliably. The first drives were 100 tpi (that's right), later to become 96 tpi so that you could double step 96 tpi to read 48 tpi disks. "Quad density" is an advertising gimmick that stuck. It is nothing more than double density with twice the tracks, erg "quad capacity" should have been the name. Transfer rate is the same 250K/bits/sec. 8" single density is also this rate, only the DD use 500k, which was only about 15% slower than first PC hard drives -- Bill Vermillion - UUCP: uunet!tarpit!bilver!bill : bill@bilver.UUCP
sprague.wbst311@xerox.com (12/17/90)
> What do you mean by "quad"? I've heard it used several different > ways. Quad meaning either the high density disks (1200k), or the > DD 96tpi. If you're talking about the latter, it should be the > same rate as DSDD, 48tpi. Quad density and High density are *NOT* the same thing, even though they both have 96tpi. You did answer my question though. :-) Thanks. ~ Mike (Sprague.Wbst311@Xerox.Com)
donm@pnet07.cts.com (Don Maslin) (12/18/90)
sprague.wbst311@XEROX.COM writes: >Hmmm, I knew both of those, but what is the transfer rate for a quad density >drive? I assume 250K bits/sec? > Assuming you mean the 96 tpi 720K 5.25", yes. Keeper of the CP/M System Disk | UUCP: {nosc ucsd crash ncr-sd}!pnet07!donm Archives for the Dino(saur)SIG | ARPA: simasd!pnet07!donm@nosc.mil - San Diego Computer Society - | INET: donm@pnet07.cts.com
tom@astro.as.arizona.edu (Thomas J. Trebisky) (12/18/90)
Michael_D._Sprague sprague.wbst311@xerox.com writes: > >> The 1.2M floppy format uses the same data-transfer rate as an 8" drive >> (500Kbits/sec). This is also true for 1.44M drives. >> 360K floppies use the standard 250Kbits/sec. >Hmmm, I knew both of those, but what is the transfer rate for a quad density >drive? I assume 250K bits/sec? I believe what is refered to as quad-density is also known as a 720k drive, (the nomenclature is a bit sloppy, quad density means different things in different contexts) and indeed has a 250kb/s xfer rate - the density being acheived by higher track density (96tpi instead of the usual 48tpi). BTW, for you transfer rate trivia freaks, did you know that a floppy written on a 360kb drive and later read on a 1.2M drive (AT, HD 5.25in) has a xfer rate of 300kb/s since the 1.2M drive rotates at 360 rpm, but the 360kb drive rotated at 300rpm - this in part explains why you can read 360kb floppies on such drives, but may have trouble writing to them (the other part is probably the slimmer heads on the 1.2M drive).