steve@thumper.UUCP (02/20/87)
A friend claims to have heard of software that will enable the AT 1.2 Mb drive to write on floppy formatted for 360k. I would like to know if anything like this exists. Even a hardware patch would be welcome. -- -Steve Miller ihnp4!bellcore!thumper!steve "The Fantasy Factory" is a trademark of Image Space, a New Jersey corporation.
john@viper.UUCP (02/22/87)
In article <409@thumper.UUCP> steve@thumper.UUCP writes: >A friend claims to have heard of software that will enable the AT 1.2 Mb >drive to write on floppy formatted for 360k. I would like to know if >anything like this exists. Even a hardware patch would be welcome. >-- > -Steve Miller ihnp4!bellcore!thumper!steve > Yes, such software exists. You've probably even heard of it. It's called MS-DOS. I worked on an AT running MS-DOS 3.1 for a couple of years. You can easily read from and write to a 360k floppy in an AT 1.2meg drive. There is one limitation to this. Don't try formatting the 360k floppy in an AT drive. While ok in theory, the resulting tracks are a bit thin and it may be difficult for another PC to read the track/sector markings. Format the floppy on a normal PC and then use at will. No special software is required.... --- John Stanley (john@viper.UUCP) Software Consultant - DynaSoft Systems UUCP: ...{amdahl,ihnp4,rutgers}!{meccts,dayton}!viper!john
pitaro@savax.UUCP (02/23/87)
> A friend claims to have heard of software that will enable the AT 1.2 Mb > drive to write on floppy formatted for 360k. I would like to know if > anything like this exists. Even a hardware patch would be welcome. I'm not an expert in this matter by any means however I can relate my experience on a true IBM AT. I frequently want to download software from our UNIX machine to my PC but I don't like doing this at 1200 baud. Fortunately we have an ethernet connection to an IBM AT which is running FTP software. To get the files onto my IBM XT at home I format the 360K floppies on my IBM XT and then insert the formatted floppy into the 1.2M drive in the IBM AT. I then download the software onto the 360K disk. When I get home I have no trouble reading and writting that disk but just because I'm paranoid I copy that disk to another disk on my XT. (So that my drive is doing the writing). I then reformat the "transfer" disk for use next time. At least from these experiences I wouldn't worry about special software unless this method doesn't work for you. Michael Pitaro USMail: Sanders Associates UUCP: decvax!savax!pitaro MER24-1583C PHONE: +1 (603) 885-9036 CS 2034 HOME: 46-D Hampshire Drive Nashua, NH 03063-2034 Nashua, NH 03063
zhahai@gaia.UUCP (02/24/87)
In article <409@thumper.UUCP> steve@thumper.UUCP writes: >A friend claims to have heard of software that will enable the AT 1.2 Mb >drive to write on floppy formatted for 360k. I would like to know if >anything like this exists. Even a hardware patch would be welcome. > -Steve Miller ihnp4!bellcore!thumper!steve First off, standard PC-DOS for the AT will both read and write 360K floppy diskettes on the 1.2M drives; this is automatic and needs no special setup. However.... the 1.2M drives have thinner head gaps (96 tracks per inch) than the 360K drives (48 tpi). This means that when a track is written on the 96 tpi drive and then read on the 48tpi drive, the latter will also pick up some "noise" on either side of the recorded data, thus reducing the noise margin. The result is that this is not always reliable; some people have written hundreds of disks on a 96 tpi drive (like the AT's 1.2M) and read them on 360 drives with no problems, other people have had many problems. The former can turn into the latter if either of the drives drifts out of alignment a little bit (or some other factor changes and reduces the noise margin just that little bit more to push it over into unreliablity). I have never heard of problems with writing on a 360K drive and reading on a 1.2 M drive. Theoretically, the thinner head would pick up no extra noise, but somewhat less signal, but this seems to always stay within the margins. (By the way, all of this applies to 720/800K 96 tpi drives as well as 1.2M 96 tpi drives). Many people believe that you reduce the problem by formatting the 360K disks on a 360K drive before writing via a 1.2M drive. This way at least the address marks (which are written only once, at format time) will be reliable. This is what I do, though I have no empirical evidence that it works better (I happen to have good results between my 360/1.2 M drives most of the time, but I don't count on it continuing). After all, it is guaranting that there will be wide track remnants around the edges of the new narrow track laid down by the 1.2 M drive. The answer: if you do not have handy 360K drives for your AT, go ahead and write 360K disks on the 1.2 M drives - but don't delete anything until you successfully read the disks on your 360K only drives; copy the files to a hard disk or to 360K disks if you want to be sure it will still be readable next week (ie: never user 360K disks written on a 1.2 M drive for archives). Oh, yes, 360K disks written on a 1.2 M drive seem to read well on another 1.2M drive (both have thin head gaps). Or for that matter, I have a 96 tpi drive on my PC (gets 720/800 K on a standard diskette, got this before the 1.2 M "HD" drives came out in this country with the AT) - this drive reads 360K disks written on the AT fine, as you would expect. With the proper software (which I have heard rumors of but have not found, sigh), I could read and write my 720/800K diskettes on the AT's 1.2M drives. (The 800K figure comes from Jformat's ability to cram 10 rather than 9 sectors per track by reducing the inter-sector gaps. Jformat and Qdrive are a format program and installable device driver pair from Tall Tree which I use on my PC to handle the 96tpi drive there. The 96 tpi drive on my PC (TEAC 55F) writes data in the same linear density as the normal 48 tpi 360K drives, and uses the same controller; the 1.2M drive in the AT packs bits more tightly to get the higher capacity, using a different controller as well as different diskette coatings to get 1.2M - but includes the ability to read/write the old linear density for compatiblity). ~z~ -- Zhahai Stewart {hao | nbires}!gaia!zhahai
coulter@hpclisp.UUCP (02/25/87)
If you decide to format a 360K floppy in a 1.2Mb drive, you need to use the \4 option on format. I have read that some 360K drives will have trouble reading the resulting floppy, but I haven't encountered any problems. -- Michael Coulter ...ucbvax!hpca!hpclld!coulter
casper@osiris.UUCP (02/25/87)
I too have used the 1.2M drive to write to low density disks
for quite some time and found it very convenient and reliable.
I definately agree with the suggestion to not try formatting in 360K
mode, but also I would like to point out that IBM does not recommend writing
to 360K disks in the 1.2M drive because of the much more narrow and dense
track that it writes.
When making disks to be distributed to people with various types
of machines I make sure that the disks have never been written to in any way
by a 1.2M drive. This is because I have had complaints from people that the
disks would work fine in an IBM they had, but then cause read errors on another
look-alike. I have also heard stories of IBM/PC's that refuse to read such
disks.
Dave Gerdes uiucuxc!osiris!casperrick@uwmacc.UUCP (02/27/87)
In article <7700005@osiris> casper@osiris.cso.uiuc.edu writes: > > When making disks to be distributed to people with various types >of machines I make sure that the disks have never been written to in any way >by a 1.2M drive. This is because I have had complaints from people that the >disks would work fine in an IBM they had, but then cause read errors on another >look-alike. I have also heard stories of IBM/PC's that refuse to read such >disks. Absolutely true. This happened to a programmer I know. He got the final version of his program all set for his presentation, copied the disks, ran it once on an AT to make sure that the copies worked, and went off to the demo. "General Error Reading Disk: Abort, Retry, Ignore?" and its all because he didn't eat his vegetables...I mean, because he didn't know about the eccentricities of the 1.2 Mb drives in writing. PS: He went back home, tried them in the same AT, and they still workedd He was really confused till he told someone who had experience in a mixed machine environment who knew what must have happened. -- "I'll do it -- I've got the GUTS. I'm the PRESIDENT." "Maybe we should take that box away from him." "Why bother?" Rick Keir -- one floor up from the Oyster Tank -- UWisc - Madison {allegra, ihnp4, seismo}!uwvax!uwmacc!rick