Thread View: comp.sys.ibm.pc.programmer
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2 total messages
Started by Hi Ho Silver
Sun, 01 Jul 1990 16:08
Re: 1.6 mb diskettes
Author: Hi Ho Silver
Date: Sun, 01 Jul 1990 16:08
Date: Sun, 01 Jul 1990 16:08
51 lines
3184 bytes
3184 bytes
$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! /
Re: 1.6 mb diskettes
Author: Chris Petrilli
Date: Sat, 07 Jul 1990 16:29
Date: Sat, 07 Jul 1990 16:29
28 lines
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2401 bytes
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."
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