as2d+@andrew.cmu.edu (Alan Henry Stein) (07/10/89)
I am currently putting together a new computer and have a question. I have read all the warning (in the DOS manual etc.) about writing to a 360k disk in a 1.2 meg drive (disk formatted at 360k) and then not being able to read it in true 360k drives. I have also read about similar compatibility problems between 1.44meg and 720k drives. Anyone have a problem with this type of compatibility or come up with a solution to it (other than putting in both HD and DD drives)?? thanks, alan
brown@astroatc.UUCP (Vidiot) (07/11/89)
In article <IYiAOwy00UhBI1IEMx@andrew.cmu.edu> as2d+@andrew.cmu.edu (Alan Henry Stein) writes:
<
<I am currently putting together a new computer and have a question. I have
<read all the warning (in the DOS manual etc.) about writing to a 360k disk
<in a 1.2 meg drive (disk formatted at 360k) and then not being able to read
<it in true 360k drives. I have also read about similar compatibility problems
<between 1.44meg and 720k drives. Anyone have a problem with this type of
<compatibility or come up with a solution to it (other than putting in both
<HD and DD drives)??
First off the problem of writing 360K diskettes on a 1.2M drive is a real
problem. The only way is to have both a 1.2M and a 360K drive. I haven't
decided if I want my second drive to be a 360K or a 1.44M. I can't have
both (internal).
But, there isn't a problem with 1.44M and 720K 3.5" drives. At least no
different than the fact that you can't read a 1.2M floppy in a 360K drive.
The 1.44/720 deal is that if a floppy is formatted for 1.44M, it will not
be readable on a 720K drive, though a 1.44M drive can make 720K diskettes that
are 100% compatable with 720K drives only. The deal there is that the
track density doesn't change when going from 720K to 1.44M (and vice-versa);
the flux density changes.
So, if you make 3.5" diskettes, you need to find out what size drive the
person has that you are making them for.
--
harvard\ att!nicmad\
Vidiot ucbvax!uwvax..........!astroatc!brown
rutgers/ decvax!nicmad/
ARPA/INTERNET: brown%astroatc.UUCP@spool.cs.wisc.edudave@westmark.UUCP (Dave Levenson) (07/11/89)
In article <IYiAOwy00UhBI1IEMx@andrew.cmu.edu>, as2d+@andrew.cmu.edu (Alan Henry Stein) writes: > > I am currently putting together a new computer and have a question. I have > read all the warning (in the DOS manual etc.) about writing to a 360k disk > in a 1.2 meg drive (disk formatted at 360k) and then not being able to read > it in true 360k drives. I have also read about similar compatibility problems > between 1.44meg and 720k drives. Anyone have a problem with this type of > compatibility or come up with a solution to it (other than putting in both > HD and DD drives)?? Alan: We sell software and support customer sites who use a mix of XT- and AT-class machines. Originally, we used only a 1.2 Mbyte diskette drive, and formatted HD and DD diskettes diskettes in it for distribution. What we found was that if we bulk-erased the media before formatting it, we could reliably read the DD diskettes that we formatted on the HD drive. If we attempted to format the DD diskettes which had previously been formatted on a true DD drive, without bulk-erasing them first, we had occasional GENERAL FAILURE READING DRIVE A: troubles in the field. The real problem, however, was when we took one of these "cross-formatted" diskettes into the field and tried to add one file to it by writing on it using a true DD drive. That would almost always foul it up and make it unreadable on both DD and HD drives. We have now installed both DD and HD diskette drives in our development machines, so that we can reliably send diskettes to the field and collect information and bring them back! -- Dave Levenson Voice: (201) 647 0900 Westmark, Inc. Internet: dave@westmark.uu.net Warren, NJ, USA UUCP: {uunet | rutgers | att}!westmark!dave [The Man in the Mooney] AT&T Mail: !westmark!dave
nghiem@walt.cc.utexas.edu (Alex Nghiem) (07/11/89)
In article <2250@astroatc.UUCP> brown@astroatc.UUCP (Vidiot) writes: >First off the problem of writing 360K diskettes on a 1.2M drive is a real >problem. The only way is to have both a 1.2M and a 360K drive. Not true. I've worked on a Compaq Portable III with a dual speed 1.2 that could format a 360K that can be read on a standard PC. The problem I have is identifying who makes the drive. I know that Teac, Toshiba, and Fujitsu make dual speed 1.2 megs. I trying to find out which one works best. (Please send E-mail. I'll summarize and post to the net.) nghiem@walt.cc.utexas.edu !cs.utexas.edu!ut-emx!walt!nghiem
ritchie@hpldola.HP.COM (Dave Ritchie) (07/12/89)
>In article <2250@astroatc.UUCP> brown@astroatc.UUCP (Vidiot) writes: > >>First off the problem of writing 360K diskettes on a 1.2M drive is a real >>problem. The only way is to have both a 1.2M and a 360K drive. > >Not true. I've worked on a Compaq Portable III with a dual speed >1.2 that could format a 360K that can be read on a standard PC. >The problem I have is identifying who makes the drive. I know >that Teac, Toshiba, and Fujitsu make dual speed 1.2 megs. I >trying to find out which one works best. > >(Please send E-mail. I'll summarize and post to the net.) > >nghiem@walt.cc.utexas.edu >!cs.utexas.edu!ut-emx!walt!nghiem >---------- This is true iff you bulk-erase the diskettes and reformat in 360K format on the 1.2M drive. If you write to these disks with a 360K drive, the wider track of the 360K drive can cause problems later when writing with a 1.2M drive. This works on all of the 1.2M drives I used *which are well aligned*. (3 1/2" disks use the same track width with a different clock speed for each density - thus no incompatibility problems). Dave
ray@philmtl.philips.ca (Raymond Dunn) (07/12/89)
In article <15072@ut-emx.UUCP> nghiem@walt.cc.utexas.edu (Alex Nghiem) writes: >In article <2250@astroatc.UUCP> brown@astroatc.UUCP (Vidiot) writes: > >>First off the problem of writing 360K diskettes on a 1.2M drive is a real >>problem. The only way is to have both a 1.2M and a 360K drive. > >Not true. I've worked on a Compaq Portable III with a dual speed >1.2 that could format a 360K that can be read on a standard PC. >The problem I have is identifying who makes the drive. I know >that Teac, Toshiba, and Fujitsu make dual speed 1.2 megs. I >trying to find out which one works best. > >(Please send E-mail. I'll summarize and post to the net.) Please don't! As Mr. Brown says 1.2M/360K is a real problem. *ALL* 1.2Meg drives are "dual speed" to enable them to read and write both 1.2M and 360K diskettes. A 1.2M drive must have a head with a gap which is about half the width of a 360K drive. A diskette written at 360K density on a 1.2M drive has a track which is half the width of that written on a 360K drive. That is the cause of the problem. It could only be overcome by having a drive with two heads, one used when dealing with 360K diskettes, the other when dealing with 1.2M. There are no such drives to my knowledge. x times out of y you "get away" with writing at 360K on a 1.2M drive and reading it on a 360K drive. X and y vary enormously from drive to drive, diskette to diskette, and the *history* of the diskette (on which density drive it was formatted, what and where it was previously written etc). When 3.5" drives *first* came out there were several compatability problems drive to drive (even within 720K). These have now all but evaporated. -- Ray Dunn. | UUCP: ..!uunet!philmtl!ray Philips Electronics Ltd. | TEL : (514) 744-8200 Ext: 2347 600 Dr Frederik Philips Blvd | FAX : (514) 744-6455 St Laurent. Quebec. H4M 2S9 | TLX : 05-824090
leonard@bucket.UUCP (Leonard Erickson) (07/12/89)
as2d+@andrew.cmu.edu (Alan Henry Stein) writes:
<I am currently putting together a new computer and have a question. I have
<read all the warning (in the DOS manual etc.) about writing to a 360k disk
<in a 1.2 meg drive (disk formatted at 360k) and then not being able to read
<it in true 360k drives. I have also read about similar compatibility problems
<between 1.44meg and 720k drives. Anyone have a problem with this type of
<compatibility or come up with a solution to it (other than putting in both
<HD and DD drives)??
I've run into the problem with 360/1.2 compatability. It can be (sort of)
avoided by only using new or bulk-erased floppies and formatting them
in the 1.2 drive. The problem is because the tracks written by the
1.2 drive are less than 1/2 as wide as the tracks written by a 360k
drive. So the 360 drive could read both old and new data at the same
time if the disk has been *written* in a 360k drive before being written
to in the 1.2 drive.
I've never heard anything but rumor about 720k/1.44 problems. I have
heard very strong statements to the effect that there are *not*
any problems. This makes sense as both are 80 track formats.
--
Leonard Erickson ...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I'm all in favor of keeping dangerous weapons out of the hands of fools.
Let's start with typewriters." -- Solomon Shortasl@otter.hpl.hp.com (Lawrence Ang) (07/12/89)
Try writing to the 360K disk in a 1.2M drive, treating it as drive B:. This solution works for some systems, and allows true 360K drives to read the disk thereafter. Lawrence Ang
keithe@tekgvs.LABS.TEK.COM (Keith Ericson) (07/13/89)
In article <1567@westmark.UUCP> dave@westmark.UUCP (Dave Levenson) writes: > > We sell software and support customer sites who use a mix of >XT- and AT-class machines. Originally, we used only a 1.2 Mbyte >diskette drive, and formatted HD and DD diskettes diskettes in it >for distribution. > > What we found was that if we bulk-erased the media before >formatting it, we could reliably read the DD diskettes that we >formatted on the HD drive. If we attempted to format the DD >diskettes which had previously been formatted on a true DD drive, >without bulk-erasing them first, we had occasional GENERAL FAILURE >READING DRIVE A: troubles in the field. > > The real problem, however, was when we took one of these >"cross-formatted" diskettes into the field and tried to add one file >to it by writing on it using a true DD drive. That would almost >always foul it up and make it unreadable on both DD and HD drives. > > We have now installed both DD and HD diskette drives in our >development machines, so that we can reliably send diskettes to the >field and collect information and bring them back! > --------------------------------------------------------------------------- Data track of a bulk erased diskette: !@#$!@#$!@#$!@#%#@$%^$()%^&%^(^&*()&*)*(&)(%^&%&%$#@ (1) (&*()%^&%^^@#$#@!%#%^&(&*()*()_%$%#!@%$*^&)(*(&@#!%$ !@#$@#%^$%^*^&(*&*)(&*(%$#%@#$%^#$^&%*^&*(&*)*(&_)(* --------------------------------------------------------------------------- Data Track of a 360K-drive formatted diskette: #################################################### (2) #################################################### #################################################### --------------------------------------------------------------------------- Data Track of a 360K-drive-formatted diskette WRITTEN with a 360K drive: 1234567890123456789012345678901234567890123456789012 \ (3) 1234567890123456789012345678901234567890123456789012 >---data 1234567890123456789012345678901234567890123456789012 / --------------------------------------------------------------------------- The above Data Track WRITTEN with a 1.2M diskette: 1234567890123456789012345678901234567890123456789012 (4) ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ <--data 1234567890123456789012345678901234567890123456789012 --------------------------------------------------------------------------- Now - guess what kind of problems the 360k-drive is going to have when it tries to read track (4). A(nother) 1.2M drive (assuming it's properly aligned) WILL be able to read track (4). kEITHe
ralf@b.gp.cs.cmu.edu (Ralf Brown) (07/13/89)
In article <5560@tekgvs.LABS.TEK.COM> keithe@tekgvs.LABS.TEK.COM (Keith Ericson) writes: [things are actually a little more complicated, so I've expanded the diagrams for a closer look] } } Data track of a bulk erased diskette: } } )(*)(&(*^(*&%*&^$(*&^$%#%#$#!@!#$@^&%%#*&^%*&^%%$$$% } ^%&$(*&%%^#*(&%*%(*&%*%#$)(*&)(*$%$%@%^$(*&)(^&^%#() } )(*)(&(*^(*&%*&^$(*&^$%#%#$#!@!#$@^&%%#*&^%*&^%%$$$% } )(*&^*&^$^&*^()^)(&*)(^(*$%*&^$*&^%(&^)(*&(*%*&^$*&^ } !@#$!@#$!@#$!@#%#@$%^$()%^&%^(^&*()&*)*(&)(%^&%&%$#@ }(1) (&*()%^&%^^@#$#@!%#%^&(&*()*()_%$%#!@%$*^&)(*(&@#!%$ } !@#$@#%^$%^*^&(*&*)(&*(%$#%@#$%^#$^&%*^&*(&*)*(&_)(* } ^#@&^%)(&*(*^&%^%#(*&%^#*(^&%)(*&^*%&$@&*^%(%&^%#&^^ } %$##!^&$##@&^%#^#@&^%#&*^%$(*&%)(*^*%$(*%)(*(^%^%#&^ } +*)(&^%*%#_)((^&$$$@)(**&_)&(&%&$#$)(**^&$^#_)(&*%&$ } %$##!^&$##@&^%#^#@&^%#&*^%$(*&%)(*^*%$(*%)(*(^%^%#&^ } }--------------------------------------------------------------------------- } Data Track of a 360K-drive formatted diskette: } } )(*)(&(*^(*&%*&^$(*&^$%#%#$#!@!#$@^&%%#*&^%*&^%%$$$% } .................................................... } #################################################### } #################################################### } #################################################### }(2) #################################################### } #################################################### } #################################################### } #################################################### } .................................................... } %$##!^&$##@&^%#^#@&^%#&*^%$(*&%)(*^*%$(*%)(*(^%^%#&^ Where the ..... is the erasing done by the tunnel-eraser after the head does the actual writing. If you look closely at the head, it looks like this: ############ ############# ############# ############ ^^^ ^^^ read/write tunnel eraser head } }--------------------------------------------------------------------------- } } Data Track of a 360K-drive-formatted diskette WRITTEN with a 360K drive: } } )(*)(&(*^(*&%*&^$(*&^$%#%#$#!@!#$@^&%%#*&^%*&^%%$$$% } .................................................... } 1234567890123456789012345678901234567890123456789012 \ } 1234567890123456789012345678901234567890123456789012 \ } 1234567890123456789012345678901234567890123456789012 \ }(3) 1234567890123456789012345678901234567890123456789012 >---data } 1234567890123456789012345678901234567890123456789012 / } 1234567890123456789012345678901234567890123456789012 / } 1234567890123456789012345678901234567890123456789012 / } .................................................... } %$##!^&$##@&^%#^#@&^%#&*^%$(*&%)(*^*%$(*%)(*(^%^%#&^ } }--------------------------------------------------------------------------- } } The above Data Track WRITTEN with a 1.2M diskette: } } )(*)(&(*^(*&%*&^$(*&^$%#%#$#!@!#$@^&%%#*&^%*&^%%$$$% } .................................................... } 1234567890123456789012345678901234567890123456789012 <-- unerased data } .................................................... } ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ \ }(4) ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ >--data } ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZ / } .................................................... } 1234567890123456789012345678901234567890123456789012 <-- unerased data } .................................................... } %$##!^&$##@&^%#^#@&^%#&*^%$(*&%)(*^*%$(*%)(*(^%^%#&^ } }--------------------------------------------------------------------------- } }Now - guess what kind of problems the 360k-drive is going to have when it }tries to read track (4). } }A(nother) 1.2M drive (assuming it's properly aligned) WILL be able to read }track (4). -- {backbone}!cs.cmu.edu!ralf ARPA: RALF@CS.CMU.EDU FIDO: Ralf Brown 1:129/46 BITnet: RALF%CS.CMU.EDU@CMUCCVMA AT&Tnet: (412)268-3053 (school) FAX: ask DISCLAIMER? Did |"Let both sides invoke the wonders of science instead of I claim something?| the terrors." --John F. Kennedy
keithe@tekgvs.LABS.TEK.COM (Keith Ericson) (07/13/89)
In article <660011@otter.hpl.hp.com> asl@otter.hpl.hp.com (Lawrence Ang) writes: >Try writing to the 360K disk in a 1.2M drive, treating it as drive B:. >This solution works for some systems, and allows true 360K drives to read ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >the disk thereafter. ^^^^^^^^^^^^^^^^^^^ I SERIOUSLY doubt it. See my posting with the "schematic" of data tracks for an intuitive "explanation" of the problem and it's lack of solution. kEITHe
mvolo@ecsvax.UUCP (Michael R. Volow) (07/14/89)
[stuff about drives that can handle 1.2M 5 1/2" diskettes but which can write on 360K diskettes sot that other 360K drives can read them] Wouldn't such a 360K/1.2M drive to have heads that can write wider (360K) or narrow (1.2M) track widths as well? M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411
jfm@cs.odu.edu (John F. Mclaurin) (07/14/89)
In article <IYiAOwy00UhBI1IEMx@andrew.cmu.edu> as2d+@andrew.cmu.edu (Alan Henry Stein) writes: > >I am currently putting together a new computer and have a question. I have >read all the warning (in the DOS manual etc.) about writing to a 360k disk >in a 1.2 meg drive (disk formatted at 360k) and then not being able to read >it in true 360k drives. [edited slightly] >compatibility or come up with a solution to it (other than putting in both >HD and DD drives)?? >thanks, alan I have used both HD and DD 5.25's in my computer and have had no problems with using these disks on my system, on a friends PC, and on several other PC's. You may find that others have had problems but I can only speak for myself. On the other hand you might consider how important that data is. BTW I didn't use good "brand" name disks, I used 0.25 ct generics. Someone with a better knowledge of hardware might give you a better explanation why there are some problems. -- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!! John F. Mclaurin jfm@cs.odu.edu Old Dominion Univ. Norfolk Va !!! !!! "Love Thy Neighbor As Thyself, Except Of Course If He is Turkish, !!! !!! Then Kill The Bastard." - Someone - In Blackadder. !!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
trr@rayssd.ray.com (Terry R. Raymond) (07/14/89)
In article <IYiAOwy00UhBI1IEMx@andrew.cmu.edu>, as2d+@andrew.cmu.edu (Alan Henry Stein) writes: > > I am currently putting together a new computer and have a question. I have > read all the warning (in the DOS manual etc.) about writing to a 360k disk > in a 1.2 meg drive (disk formatted at 360k) and then not being able to read > it in true 360k drives. Anyone have a problem with this type of > compatibility or come up with a solution to it (other than putting in both > HD and DD drives)?? > > thanks, > alan I frequently write 360k formatted disks in my 1.2m drive and read them successfully on a 360k drive. The procedure is to treat the disk as a write only by 1.2m drive disk. The disk must also be bulk erased, I use a bulk cassette eraser, before formatting. I have not had any problems with this procedure. Just make sure to NEVER write on the disk with the 360k drive unless bulk erased. Hope this helps. -- Terry Raymond Raytheon Submarine Signal Division; Portsmouth RI; (401)-847-8000 x5597 ------------------------------------------------------------------------------ Internet: trr@rayssd.ray.com (trr%rayssd.ray.com@a.cs.uiuc.edu) UUCP: {decuac,gatech,mimsy,mirror,necntc,sun,uiucdcs,ukma}!rayssd!trr
hjg@amms4.UUCP (Harry Gross) (07/15/89)
In article <IYiAOwy00UhBI1IEMx@andrew.cmu.edu> as2d+@andrew.cmu.edu (Alan Henry Stein) writes: >I am currently putting together a new computer and have a question. I have >read all the warning (in the DOS manual etc.) about writing to a 360k disk >in a 1.2 meg drive (disk formatted at 360k) and then not being able to read >it in true 360k drives. I have also read about similar compatibility problems >between 1.44meg and 720k drives. Anyone have a problem with this type of >compatibility or come up with a solution to it (other than putting in both >HD and DD drives)?? The problem between 360K and 1.2M drives is that the track on a 1.2M drive is half the width of the track on the 360K drive. Thus, even though the diskette may be formatted for 360K, if it was done on a 1.2M drive, the data is 'thinner' than if it had been done on a 360K drive. SOME 360K drives don't seem to mind, but many do. This leads to the warning stating that you MAY have problems reading the disk. In the case of the 720K vs. 1.44M drives, no such problem exists. The data tracks are the same size on both drives. The only difference is whether or not data is recorded on one side, or both sides. Thus, a good mix of floppy drives would be 1 each: 360K drive (probably as drive A) 1.2M drive (probably as drive B) 1.44M drive (what ever you wish - D? E?, etc., but probably NOT C) Hope this helps -- Harry Gross | reserved for | something really Internet: hjg@amms4.UUCP (we're working on registering)| clever - any UUCP: {jyacc, rna, bklyncis}!amms4!hjg | suggestions?
trgauchat@rose.waterloo.edu (Terry Gauchat) (07/17/89)
In article <561@amms4.UUCP> hjg@amms4.UUCP (Harry Gross) writes: }In the case of the 720K vs. 1.44M drives, no such problem exists. The data }tracks are the same size on both drives. The only difference is whether or not }data is recorded on one side, or both sides. } Please get it through your heads...! 720K and 1.44Meg 3-1/2" drives are both DOUBLE SIDED. Both have the same number of tracks too. 1.44 Meg uses 18 sectors/track vs 9. To get this extra density, CrOxide is is used rather than Iron Oxide (think better quality cassette tapes). For digital data, however, IronOxide (DD) disks may work fine if formatted (HD). ...Terry.
djm@etive.ed.ac.uk (D Murphy) (07/17/89)
In article <561@amms4.UUCP> hjg@amms4.UUCP (Harry Gross) writes: >> >In the case of the 720K vs. 1.44M drives, no such problem exists. The data >tracks are the same size on both drives. The only difference is whether or not >data is recorded on one side, or both sides. Thus, a good mix of floppy drives >would be 1 each: > > 360K drive (probably as drive A) > 1.2M drive (probably as drive B) > 1.44M drive (what ever you wish - D? E?, etc., but probably > NOT C) > >Hope this helps > >-- > Harry Gross | reserved for > | something really >Internet: hjg@amms4.UUCP (we're working on registering)| clever - any >UUCP: {jyacc, rna, bklyncis}!amms4!hjg | suggestion Umm - this ain't true. 720K 3.5" drives are formatted 80 tracks/side, 9 sectors/track and use both sides. 1.44M disks use 18 sectors/track, but have the same track width. This is according to the IBM manual *and* the MS Programmers reference. I also know its true cos I wrote a program to replicate some wierd sector formatting using this as a basis and it worked. The head addressed in the read/write operation is one of the parameters in the BIOS call (13h, I think), and you also pass this when writing directly to the FDC. I have a 720K as a second floppy on my PC, and trying to get it to format to 1.44M by writing direct to the FDC doesn't work - presumably the old NEC controller couldn't address 18 sectors because it only has an 8 bit sector address register. Incidentally - even if it were true it wouldn't matter because you can't just turn a 3.5" disk over to use the other side like you could with a 5.25" - there is a diagonal cut-out in the top right-hand corner which stops it being put in the wrong way, and the hub is only exposed on one side. Murff.... JANET: djm@uk.ac.ed.etive Internet: djm%ed.etive@nsfnet-relay.ac.uk Murff@uk.ac.ed.emas-a Murff%ed.emas-a@nsfnet-relay.ac.uk trinity@uk.ac.ed.cs.tardis trinity%ed.cs.tardis@nsfnet-relay.ac.uk D.J. Murphy *Artificial* intelligence ? Evidently.....
ronald@ibmpcug.UUCP (Ronald Khoo) (07/21/89)
In article <597@philmtl.philips.ca> ray@philmtl.philips.ca (Raymond Dunn) writes:
! A 1.2M drive must have a head with a gap which is about half the width of a
! 360K drive.
!
! A diskette written at 360K density on a 1.2M drive has a track which is half
! the width of that written on a 360K drive. That is the cause of the problem.
! It could only be overcome by having a drive with two heads, one used when
! dealing with 360K diskettes, the other when dealing with 1.2M. There are no
! such drives to my knowledge.
I actually heard some *rumour* that a new NEC (?) drive is sort-of such
beast, except that it is the same head with two different effective widths
depending on which density is selected (two windings switchable between
opposing and aiding, I guess ?) NEC here in the UK seems to be keeping their
head down about this drive, so DATA% is scarce.
Can anyone confirm/deny this rumour?
------
% DATA seems to be a trademark of John Mashey <mash@mips.com>
--
Ronald.Khoo@ibmpcug.CO.UK (The IBM PC User Group, PO Box 360, Harrow HA1 4LQ)
Path: ...!ukc!slxsys!ibmpcug!ronald Phone: +44-1-863 1191 Fax: +44-1-863 6095
Disclaimer: With my opinion of PCs, ibmpcug probably disclaims knowledge of me!iiit-sh@cybaswan.UUCP (Steve Hosgood) (07/21/89)
In article <11079@ibmpcug.UUCP> Ronald.Khoo@ibmpcug.CO.UK writes: >In article <597@philmtl.philips.ca> ray@philmtl.philips.ca (Raymond Dunn) writes: >! A diskette written at 360K density on a 1.2M drive has a track which is half >! the width of that written on a 360K drive. That is the cause of the problem. >! It could only be overcome by having a drive with two heads, one used when >! dealing with 360K diskettes, the other when dealing with 1.2M. There are no >! such drives to my knowledge. > >I actually heard some *rumour* that a new NEC (?) drive is sort-of such >beast, except that it is the same head with two different effective widths >depending on which density is selected (two windings switchable between >opposing and aiding, I guess ?) NEC here in the UK seems to be keeping their >head down about this drive, so DATA% is scarce. > >Can anyone confirm/deny this rumour? > I can - I've got one, but it's not *that* new, I've had it for about 2 years. It's an NEC FD1155C, and it works great! It was fitted as standard to the AT that the company (name below) were selling at that time, a bonus whose value I didn't realise until much later. I guess it's the split-head system, but I don't know. FYI, it came from: Comcen Technology Ltd, 45/51 Wychtree St, Morriston, Swansea SA6 8EX, UK. I have no involvement with this company - just a satisfied customer. Steve -----------------------------------------------+------------------------------ Steve Hosgood BSc, | Phone (+44) 792 295213 Image Processing and Systems Engineer, | Fax (+44) 792 295532 Institute for Industrial Information Techology,| Telex 48149 Innovation Centre, University of Wales, +------+ JANET: iiit-sh@uk.ac.swan.pyr Swansea SA2 8PP | UUCP: ..!ukc!cybaswan.UUCP!iiit-sh ----------------------------------------+------------------------------------- My views are not necessarily those of my employers!
leilabd@syma.sussex.ac.uk (Leila Burrell-Davis) (07/21/89)
We are using a Sysgen Bridge-File 360K/1.2Mb external 5.25" drive on a PS/2-50Z. We have been formatting 360K disks without difficulty and copying files to them from 3.5" disks. None of the people for whom we have done this has complained that they couldn't read the disks on their 360K drives. We have so far only used new disks for this purpose, however. -- Leila Burrell-Davis, Computing Service, University of Sussex, Brighton, UK Tel: +44 273 678390 Fax: +44 273 678335 JANET: leilabd@uk.ac.sussex.syma ARPA: leilabd%syma.sussex.ac.uk@nsfnet-relay.ac.uk BITNET: leilabd@syma.sussex.ac.uk UUCP: leilabd@syma.uucp
mvolo@ecsvax.UUCP (Michael R. Volow) (07/22/89)
Zounds! it was there all the time. Got a NEC 1.2 M for my IBM PC a year ago. Have been following to the discussion on 1.2 M compatibil- ity for 360K diskettes. I bulk erased two 360 K diskettes and formatted one in the 360k drive and one in the 1.2M drive. Then I created a test file in each drive and overwrote it multiple times with the other drive and also with the original drive. Both drives could read both test files no matter which was the last drive to have overwritten the file last. The acid test was that the 360 could read test files that had been overwritten by the supposedly narrow-tracked drive, regard- less of which drive had done the formatting, and regardless of which drive had done the last overwrite. I assume the overwriting was takin place in the same sector as the file remained relatively short. Any other tests I should do? M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411
mvolo@ecsvax.UUCP (Michael R. Volow) (07/22/89)
Regarding further testing of the 360K compatibility of the NEC 1.2M floppy drive: Took a 360K diskette that had been formatted in a 360K drive and had 180K data. Reformatted it in a NEC 1.2M drive again to 360K. Wrote an small text file to it in the 1.2M drive. Not only the 1.2M drive, but also the 360K drive, was able to read the text file. If the 1.2M drive only formats, reads, and writes skinny tracks, then the 360K drive should have trouble reading them, if residual data existed on either side of the 1.2M-formatted skinny tracks. Diskette had not been bulk- erased. Have not peeked inside of the 1.2M to see if there is a head wired to write in 2 effective widths. Oh yes, I did have difficulty in getting PC DOS 3.1 to format the 360K in the 1.2M drive using th3e FORMAT/4 option (wrong media message), but I used a format routine from a file manager I use (WindowDOS). Any other tests you'd like to see? M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411
wjr@ftp.COM (Bill Rust) (07/24/89)
My experience with writing 360K disks on 1.2M drives tells me don't do it. A couple years ago, a friend of mine and I bought ATT 6300+ machines from the same store. Today, with his 1.2M drive, he regularly writes 360K disks and they work in 360K drives all over the place. When I try to do the same thing, nobody can read the disks. My guess is that his drive happens to position the head precisely (much beyond tolerances) where a 360K can read it while mine doesn't. Since I have had experience with about 20 1.2M drives and his is the only one that reliably writes 360K disks, I chalk it up to him getting lucky. Personally, I wouldn't dream of putting anything important on a 360K disk with a 1.2M drive and expecting a 360K drive to read it (a 1.2M drive usually will, but that is another story). Bill Rust (wjr@ftp.com)
mvolo@ecsvax.UUCP (Michael R. Volow) (07/26/89)
There have been 2 or 3 postings that NEC 1.2 Floppy drives reliably read, write, and format 360K diskettes, along with some comments about how they might do this. Could other NEC 1.2 FD owners check this out and post their experiences. Is anyone familiar with the innards of one of these drives? M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411