WSCART01@ULKYVX.BITNET (06/27/89)
I suppose most of you are aware of 1.44 Meg drives out for the IBM. They use 160 tracks instead of the 80 tracks normal drives. The question i'm pondering is: Why has no one hooked one up to an ST? I suppose there is either a harware or software diffuculty to overcome. Does anyone know which, and exactly what the problem is? Stuart Carter | Radio astronomers can University Of Louisville | do it 24 Hours a day.
neil@cs.hw.ac.uk (Neil Forsyth) (06/27/89)
In article <8906261817.AA17231@jade.berkeley.edu>WSCART01@ULKYVX.BITNET writes: > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They >use 160 tracks instead of the 80 tracks normal drives. I thought 4HD drives meant quad density. ie. 18 sectors/track instead of 9 but still 80 tracks. Anyone want confirm/deny this? _____________________________________________________________________________ / DISCLAIMER: Unless otherwise stated, the above comments are entirely my own \ ! "I think all right thinking people in this country are sick and tired of ! ! being told that ordinary decent people are fed up in this country with ! ! being sick and tired. I'm certainly not and I'm sick and tired of being ! ! told that I am!" - Monty Python ! ! ! ! Neil Forsyth JANET: neil@uk.ac.hw.cs ! ! Dept. of Computer Science ARPA: neil@cs.hw.ac.uk ! ! Heriot-Watt University UUCP: ..!ukc!cs.hw.ac.uk!neil ! ! Edinburgh, Scotland !
hase@netmbx.UUCP (Hartmut Semken) (06/27/89)
In article <8906261817.AA17231@jade.berkeley.edu> WSCART01@ULKYVX.BITNET writes: > > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They >use 160 tracks instead of the 80 tracks normal drives. They do not use 2*160 Tracks. They use a faster bit stream (higher density) and special media. The ST floppy controller cannot handle 2/1.44 Meg floppies. hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP If there is something more important than my Ego, I want it caught and shot. Now! (Zaphod Beeblebrox)
dclemans@mentor.com (Dave Clemans @ APD x1292) (06/27/89)
From article <8906261817.AA17231@jade.berkeley.edu>, by WSCART01@ULKYVX.BITNET: > > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They > use 160 tracks instead of the 80 tracks normal drives. The question i'm > pondering is: Why has no one hooked one up to an ST? I suppose there is > either a harware or software diffuculty to overcome. Does anyone know > which, and exactly what the problem is? > 1.44 Meg drives are NOT 160 track drives; they are 80 track drives. The difference is the bit rate to/from the drive; 1.44 Meg drives are twice as fast, and thus can store twice as much data. The Western Digital disk controller chip used by the ST is not able to handle anything other than the current clock rates. If you want to use a 1.44 Meg drive on an ST, the only known alternatives are: buy a "Discovery Cartridge" find a 1.44 Meg floppy with a SCSI interface, and treat it as a small hard disk do some MAJOR hacking on the mother board and in the OS to switch to a more general disk controller dgc
kirkenda@psueea.uucp (Steve Kirkendall) (06/28/89)
In article <8906261817.AA17231@jade.berkeley.edu> WSCART01@ULKYVX.BITNET writes: > > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They >use 160 tracks instead of the 80 tracks normal drives. The question i'm >pondering is: Why has no one hooked one up to an ST? I suppose there is >either a harware or software diffuculty to overcome. Does anyone know >which, and exactly what the problem is? Actually, the 1.44M drives are 80-track double-sided drives, just like 720K drives. The difference is that they store 18 sectors per track instead of 9. To do this, they have to read/write data at a higher data rate. The disk controller built into STs can't operate at the higher data rate, so the first thing you would have to do is find a version of the controller chip that can handle the higher data rate. The next thing you would have to do is write a new device driver that exploits the higher data rate of the new controller. Finally, to do it right you would have to add a new line to the cable that goes out to the floppy, to allow the ST to detect the "high density" mark on the diskette. (3.5" 1.44M diskettes have an extra hole, simililar to the write-protect hole, to indicate that they can be formatted at 1.44M). You want detailed descriptions with part numbers, pin numbers, and source code? Sorry. I don't have that information. BTW, about 80% of the PCs out there can't use 1.44M drives, even if they have the right hardware, because the PC's BIOS only supports about half a dozen different formats and, for older PCs, nobody thought to add that precise configuration. This is changing, sure, but don't expect 1.44M to be the next industry standard. -- Steve Kirkendall ...uunet!tektronix!psu-cs!kirkenda
hyc@math.lsa.umich.edu (Howard Chu) (06/28/89)
In article <8906261817.AA17231@jade.berkeley.edu> WSCART01@ULKYVX.BITNET writes: > > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They >use 160 tracks instead of the 80 tracks normal drives. The question i'm >pondering is: Why has no one hooked one up to an ST? I suppose there is >either a harware or software diffuculty to overcome. Does anyone know >which, and exactly what the problem is? Sure, the WD1772 floppy controller chip in the ST can't handle the data density. It's only able to handle single and double density, which amounts to 125 and 250kbits/sec. The density select line is also permanently wired for double-den... If Western Digital has a somewhat-compatible newer controller chip that you can use, it shouldn't be too hard to upgrade, but for now, it wouldn't be easy. -- -=- PrayerMail: Send 100Mbits to holyghost@father.son[127.0.0.1] and You Too can have a Personal Electronic Relationship with God!
chasm@killer.DALLAS.TX.US (Charles Marslett) (06/28/89)
In article <8906261817.AA17231@jade.berkeley.edu>, WSCART01@ULKYVX.BITNET writes: > > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They > use 160 tracks instead of the 80 tracks normal drives. The question i'm > pondering is: Why has no one hooked one up to an ST? I suppose there is > either a harware or software diffuculty to overcome. Does anyone know > which, and exactly what the problem is? The 1.44 MB drives, like the 1.2 MB 5 1/4" drives, still have 80 tracks of data, but they just write more data on each track. In particular, they typically use an 8" drive data rate (like the 1.2 MB drives), so they get twice as many bits per track. (BTW, the reason the 5 1/4" drives don't get 1.44 MB per disk, like the 3 1/2" drives, is that in their case, the drive actually spins faster when the higher data rate is in use, so they don't write quite twice as many bits per track. The problem with using such a drive on the Atari ST is that the controller chip used cannot run that fast (does anyone know if a pin compatible controller has ever been released by Western Digital or one of their com- petitors? That would make this possible.). > Stuart Carter | Radio astronomers can > University Of Louisville | do it 24 Hours a day. =========================================================================== Charles Marslett STB Systems, Inc. <== Apply all standard disclaimers Wordmark Systems <== No disclaimers required -- that's just me chasm@killer.dallas.tx.us <== soon to be attctc.dallas.tx.us I think
dlm@druwy.ATT.COM (Dan Moore) (06/28/89)
in article <8906261817.AA17231@jade.berkeley.edu>, WSCART01@ULKYVX.BITNET says: > I suppose most of you are aware of 1.44 Meg drives out for the IBM. They > use 160 tracks instead of the 80 tracks normal drives. The 1.44 Meg high density drives are not 160 track drives, they are 80 track drives just like the STs. The difference is in the number of sectors per track (actually the bit rate on the disk is higher). Normally the ST uses 9 sectors per track, 10 sectors works reliably, 11 will work on drives that are spinning much slower than the spec says (about 290 RPM instead of 300 RPM). All these sectors are written with a 2 micro-second bit interval. The 1.44 Meg drives put twice as much data, 18 sectors, on a track. This is done by using a 1 micro-second bit interval, a different magnetic coating on the disks which can handle the higher bit rate, and a different head design on the disk drive which can handle the stronger currents used to write on the disks. > The question i'm > pondering is: Why has no one hooked one up to an ST? I suppose there is > either a harware or software diffuculty to overcome. Does anyone know > which, and exactly what the problem is? The ST floppy controller doesn't support the 1 micro-second bit interval, it only supports 2 micro-seconds. So you'd have to replace the floppy controller with one that can handle both (you do want to read your current disks don't you?), replace the current floppy with a drive that can handle the high density disks and then re-write the BIOS floppy disk code to support whatever floppy disk controller you inserted. Of course all the third party programs that go directly to the floppy controller will break (Spectre 128, Twister, DCFormat, etc.). Dan Moore AT&T Bell Labs Denver dlm@druwy.ATT.COM