angerhof@esunix.UUCP (Norman Angerhofer) (03/11/88)
I would like to put a 3.5" floppy drive into an AT-clone (which will hopefully
have the BIOS to support this kind of drive.) The 1.44 Mb drives are only
slightly more expensive than the 720K drives. But the floppies for them
are more than twice as expensive!
So, I am thinking, I'll get a 1.44 Mb drive and use the 720K floppies until
floppy prices go down enough to be able to afford the 1.44Mb floppies.
My question: do the 1.44MB 3.5" drives also RELIABLY read and write the
720k format?
Thanks,
--Norman
Norman Angerhofer uucp: ...{decvax,ucbvax,ihnp4}!decwrl!esunix!angerhof
540 Arapeen Dr. or ...ihnp4!utah-cs!esunix!angerhof
SLC, UT 84108 ARPA: angerhof%esunix.uucp@cs.utah.edurps@homxc.UUCP (R.SHARPLES) (03/14/88)
In article <746@esunix.UUCP>, angerhof@esunix.UUCP (Norman Angerhofer) writes: > I would like to put a 3.5" floppy drive into an AT-clone (which will hopefully > have the BIOS to support this kind of drive.) ... > > My question: do the 1.44MB 3.5" drives also RELIABLY read and write the > 720k format? > > Thanks, > > --Norman I have just done this in my PC's Limited 386/16. I have yet to get it to work properly. The PCL supports 720 and 1.44meg in its system setup. I bought a Mitsubishi 1.44meg drive from Eltek (not recommended, the drive arrived without paperwork or hardware, they sent hardware but they claim there is no paperwork - makes it fun trying to set the jumpers). I also bought DOS 3.3 to support the 1.44meg formatting. I had to set the system setup as a 1.44meg on drive B, if set as 720K the system cries foul on boot and asks me to correct the error. If I boot DOS 3.3 in the A drive (my hd is 3.2) it can read/write/format the B drive as 1.44meg (even on 720K floppies). However, if you follow the MS DOS directions for formatting a 1.44meg as 720K: format b: /t:80 /n:9 you get the error "invalid parameter". According to someone at the MS help #, this is an acknowledged bug - e.g. you can not format a 1.44meg as 720K under DOS 3.3 at this time. (I am not sure he knew what he was talking about.) HOWEVER, I am not at all sure that the drive is installed correctly. If you place a formatted 720K disk in it, it will read it fine. If you try to write to it, it will clobber the disk. Perhaps some jumper must be set, I don't know. The MS support person readily admitted that there was a problem in DOS 3.3 but seemed to have little understanding of what that problem might be. I think the problem is that either DOS can not tell the drive to, or the drive cannot switch to the lower density format (on 1.2 meg drives this involves a different speed as well as track spacing). This may be controlled by one of the mysterious jumpers on the drive. So, anyone else have a clue? Russ Sharples homxc!rps NOTE: The above in NO WAY reflects the opinions of AT&T. These opinions are my own and the results of un-scientific and highly irregular analysis methods.
wew@naucse.UUCP (Bill Wilson) (03/14/88)
The new 1.44 Meg 3 1/2" drives are not like the 1.2 meg drives that came out with the AT's. Instead of doubling the number of tracks they paclk more information on each track. This being the case you can reliably use 720K disks without any problems. We have model 50's and 30's on campus and have not had any problems going between them yet. Bill Wilson
burgin@ecsvax.UUCP (Robert Burgin) (03/17/88)
In article <1528@homxc.UUCP>, rps@homxc.UUCP (R.SHARPLES) writes: > In article <746@esunix.UUCP>, angerhof@esunix.UUCP (Norman Angerhofer) writes: > > > > My question: do the 1.44MB 3.5" drives also RELIABLY read and write the > > 720k format? > > I have just done this in my PC's Limited 386/16. I have yet to get it > to work properly... > ... However, if you follow > the MS DOS directions for formatting a 1.44meg as 720K: > format b: /t:80 /n:9 > you get the error "invalid parameter". According to someone at the > MS help #, this is an acknowledged bug - e.g. you can not format a > 1.44meg as 720K under DOS 3.3 at this time... I have followed this discussion about 1.44 meg drives and 720K disks for some time and can't understand what the fuss is all about. I have a Tandy 4000 with a 1.44 meg drive, and it handles 720K disks with no trouble. I did have some problems until I got a copy of DOS 3.3 and discovered 'FORMAT B: /T:80 /N:9' And it works. Maybe I'm lucky? --rb P.S. I always reverse the parameters -> 'FORMAT B: /N:9 /T:80' Maybe that's the ticket?
soley@ontenv.UUCP (Norman S. Soley) (03/17/88)
In article <746@esunix.UUCP>, angerhof@esunix.UUCP (Norman Angerhofer) writes: > I would like to put a 3.5" floppy drive into an AT-clone (which will hopefully > have the BIOS to support this kind of drive.) The 1.44 Mb drives are only > slightly more expensive than the 720K drives. But the floppies for them > are more than twice as expensive! > > So, I am thinking, I'll get a 1.44 Mb drive and use the 720K floppies until > floppy prices go down enough to be able to afford the 1.44Mb floppies. > > My question: do the 1.44MB 3.5" drives also RELIABLY read and write the > 720k format? I can't claim direct experience but in theory it should be no problem. The 1.2 MEG 5.25" disks had an increased number of tracks and therefore a thinner read/write head. These heads wrote 360K disks by laying a thin track down the middle of the wider track. 360K drives could not reliably read the thinner track. The new 1.44 format uses the same track width as 720K disks and therefore this is not a problem. They just pack more sectors on per track. -- Norman Soley - Data Communications Analyst - Ontario Ministry of the Environment UUCP: utzoo!lsuc!ncrcan!---\ VOICE: +1 416 323 2623 {utzoo,utgpu}!sickkids!ontenv!norm ENVOY: N.SOLEY {mnetor,utgpu}!ontmoh/