6500chng@ucsbuxa.ucsb.edu (B. N. Cheng) (06/12/90)
Recently, I bought a 3-M high density diskette and noticed that it was labelled 1.6 mb. Is it possible to format that many megs into the floppy using a standard AT 1.2 meg disk drive ? Perhaps there are programs or source codes that could do this. All my attempts have so far been unsuccessful. All my attempts to
angelini@apollo.HP.COM (Bob Angelini) (06/13/90)
>6500chng@ucsbuxa.ucsb.edu (B. N. Cheng) Writes: >Recently, I bought a 3-M high density diskette and noticed that it >was labelled 1.6 mb. Is it possible to format that many megs into the >floppy using a standard AT 1.2 meg disk drive ? >Perhaps there are programs or source codes that could do this. >All my attempts have so far been unsuccessful. 1.6 Mbytes is the UNformatted capacity of the media. It is possible to gain additional formatted capacity by changing the disk format. For example: 80 Tracks X 2 sides X 15 sectors X 512 Bytes/sector = 1.288 Mbytes (less file system overhead: directory, fat ect.). 80 Tracks X 2 sides X 8 sectors X 1024 Bytes/sector = 1.311 Mbytes (less file system overhead: dir, fat ect.). Bob Angelini
drp@vpnet.chi.il.us (Douglas Pokorny) (06/21/90)
As a side note, there is a PD program called MAXI which will format 1.2 megabyte diskettes to 1.44 megs, and 1.44 meg diskettes to 1.6 megabytes. The program uses a "standard" dos format and does not require the user to load any sort of "driver" on 90% of IBM compatable hardware out there. The 10% of incompatable computers suposidly have "nonstandard bioses" and MAXI requires that you load a TSR called smax before it'll work. Does anyone know how this program is able to: a) squeeze extra space out of any type of disk (i.e. 360k, 720k, 1.2m, 1.44m) b) do the above without modification to DOS or using a device driver -Doug Pokorny (drp@vpnet.chi.il.us) +----------------------------------------------------------------------------+ | Troubleshooting hint number one: | | | | Symptom: No power indicator, no screen display, no beep, no disk | | activity. | | Solution: Make sure your computer is plugged in. | | | | "Just doing my part to help other computer users..." | +-----------------+-----------+----------------------------------------------+ | Douglas Pokorny | drp@vpnet | "I've sold my OS/9 machine and gone 80386.." | +-----------------+-----------+----------------------------------------------+
bakke@plains.UUCP (Jeffrey P. Bakke) (07/01/90)
In article <26805b48-90.2comp.sys.ibm.pc.programmer-1@vpnet.chi.il.us> drp@vpnet.chi.il.us (Douglas Pokorny) writes: > As a side note, there is a PD program called MAXI which will format 1.2 > megabyte diskettes to 1.44 megs, and 1.44 meg diskettes to 1.6 megabytes. > > The program uses a "standard" dos format and does not require the user to > load any sort of "driver" on 90% of IBM compatable hardware out there. > The 10% of incompatable computers suposidly have "nonstandard bioses" and > MAXI requires that you load a TSR called smax before it'll work. > > Does anyone know how this program is able to: > > a) squeeze extra space out of any type of disk (i.e. 360k, 720k, 1.2m, 1.44m) > b) do the above without modification to DOS or using a device driver > > -Doug Pokorny > (drp@vpnet.chi.il.us) > I currently use the MAXI program to allow me to put 420K onto 360K 5 1/4 DSDD Disks. At $0.21 a piece its a very cheap way to store information. I believe MAXI will allow you to format 720K 3.5s to 800K or so. On the 5.25s (and probably similar to the rest), the MAXI program formats the disk at 10 sectors per track instead of 9, that gives you 400K for space and then it also formats track 41 and 42 (40 & 41 for you binary thinkers)for another 20K. In using it the only thing I have found is, 1) almost every machine I've tried (Clones, and orignals) require teh TSR program to operate correctly. Without the TSR, you can read the directory but when you try and coyp files on tracks 41,42, you get seek errors. 2) This is really only a useful program for archiving up data and storing away. The method is not reliable enough to be used constantly as a reqular disk with programs and/or frequently modified data. Usually the manufacturer only has to insure that 360K will be available after a format and they don't guarantee or usually bother quality testing track 41,42. You want to use new, unused disks for the method. I personally have about 600 5.25s formatted with MAXI and when I originally formatted them, about 25-30 disks failed to format without errors under MAXI. So I suppose you could say that about 5% of normal diskettes will fail. Oh, as to how it avoids modifying dos or a device driver, the TSR program chains all of the BIOS and DOS disk write/read functions and allows almost any program to run with maxi disks (Ive never found one that doesn't) Its a good program for archives like I said, but I wouldn't use it for any constant use disk or any vital data. Jeffrey P. Bakke | Internet: bakke@plains.NoDak.edu | "Life... don't talk 2550 15th Str S #23B | UUCP : ...!uunet!plains!bakke | to me about life..." Fargo, ND 58105 | BITNET : bakke@plains.bitnet | - Marvin the PA
silver@xrtll.uucp (Hi Ho Silver) (07/01/90)
$The program uses a "standard" dos format and does not require the user to
$load any sort of "driver" on 90% of IBM compatable hardware out there.
$The 10% of incompatable computers suposidly have "nonstandard bioses" and
$MAXI requires that you load a TSR called smax before it'll work.
I've used two or three similar programs that all claim to not need a
driver on most machines. I found it rather interesting that on all the
machines I've tested them on (including some genuine IBM hardware), they
have all refused to work without the driver loaded. I haven't seen this
particular program, but I'd imagine it works similarly.
$Does anyone know how this program is able to:
$a) squeeze extra space out of any type of disk (i.e. 360k, 720k, 1.2m, 1.44m)
$b) do the above without modification to DOS or using a device driver
Yup. Standard diskettes use the following formats:
360K 720K 1.2M 1.44M
# Tracks 40 80 80 80
# Sectors 9 9 15 18
What these programs do is increase the number of tracks and/or sectors
on the diskette. For example, to put 1.44M on a 1.2M diskette, you
simply increase the number of sectors per track to 18.
The boot sector of any MS-DOS diskette includes such information as:
- the number of bytes per sector
- the number of sectors per cluster
- the number of sectors per track
- the total number of sectors in the volume
By making appropriate changes to this information, you can tell DOS
how your diskette was formatted.
One other note: if you have double-density media (360K or 720K), it
is possible to format these as if they were high-density. While you will
find a lot of sectors are reported as bad (particularly on the inner
tracks), this will usually provide a diskette with higher-than-normal
storage (typically it provides 800K on a 360K diskette). But you can't
trust these diskettes; try it with some information you don't need and
you'll find an alarming number of errors. While I would trust a diskette
formatted with a program like you mention above somewhat more than that,
I still wouldn't use it for any important information, nor would I use
it on more than one system (for reasons including the possibility of
needing a driver, and the minor differences between disk drives that mean
one may read it while another may not). Just my opinion, though.
--
/Nikebo \ Nikebo says "Nikebo knows how to post. Just do it."\silver@xrtll/
/---------\_____________________________________________________\----------/
/yunexus!xrtll!silver (L, not 1)\ Hi Ho Silver \ just silver for short /
/Silver: Ever Searching for SNTF \ Life sucks. \ someone buy me a BEER! /petrilli@walt.cc.utexas.edu (Chris Petrilli) (07/07/90)
In article <1990Jul1.160835.19622@xrtll.uucp> silver@xrtll.UUCP (Hi Ho Silver) writes: > One other note: if you have double-density media (360K or 720K), it >is possible to format these as if they were high-density. While you will >find a lot of sectors are reported as bad (particularly on the inner >tracks), this will usually provide a diskette with higher-than-normal >storage (typically it provides 800K on a 360K diskette). But you can't >trust these diskettes; try it with some information you don't need and >you'll find an alarming number of errors. While I would trust a diskette >formatted with a program like you mention above somewhat more than that, >I still wouldn't use it for any important information, nor would I use >it on more than one system (for reasons including the possibility of >needing a driver, and the minor differences between disk drives that mean >one may read it while another may not). Just my opinion, though. I have found that formatting 360K disks as a quad-density (720K) disk is very reliable, and I have backed up many a machine on to these. Every time I have treied to use the 1.2M format, it has failed to last any amount of time (because of the magnetic media), and has never correctly re-formated to a 360K again after than w/o errors as it did before. FastBack and many other backup programs will format 360K disks to 720K in a 1.2M drive and it DOES NOT require a driver to use. It is a standard DOS format that is completely understandable. + Chris Petrilli "Opinons represented here | University of Texas at Austin do not necessarily | INTERNET: petrilli@vondrake.cc.utexas.edu represent those of a sane | SNAILMAIL: 429 Brady Lane, Austin, Texas, 78746 person. Take them as + PHONE: +1 512 327 0986 simply that."