Newsgroups: comp.binaries.ibm.pc.d
Path: utzoo!utgpu!jarvis.csri.toronto.edu!me!yap
From: yap@me.utoronto.ca (Davin Yap)
Subject: Re: Formatting 720K disks to 1.44 Megs HELP!!
Message-ID: <89Nov28.223437est.19733@me.utoronto.ca>
Organization: University of Toronto, Department of Mechanical Engineering
References: <1989Nov27.212809.7241@ux1.cso.uiuc.edu> <1114@bridge2.ESD.3Com.COM>
Distribution: na
Date: Tue, 28 Nov 89 22:34:26 EST

>mbt@bridge2.ESD.3Com.COM (Brad Turner) writes:
>Why are you willing to spend the time to do a floppy disk backup
>but aren't concerned about the media you backup on? Why bother
>with the backup at all if you are knowingly going to use media
>that is suspect to failure?

I use Fastback Plus (2.08) to back-up my hard disk, using 720K disks as
1.44 Meg disks.  I use both the compression and error-correction options.
With compression, I get roughly 1.8 meg of data onto each disk.  It is
claimed that with the error-correction enabled, up to 8% (?) of the disk
can be complete garbage, but your data is still recoverable.  The only
time I've seen the error-correction portion of Fastback "show its stuff"
was recovering from disks that were not already formatted before Fastback
got its hands on them.  The error-correction works.  However, I now
pre-format the disks and have not encountered any problems since.

Incidently, I regularly use 720K disks as 1.44 Meg disks in everyday use.
In the past nine months, I've only encounted one problem disk out of some
fifty odd.  To me, the only truly important data is that which I create
myself; this I place on disks formatted to their correct density.
Perhaps I'm a 'slug', but that amounts to less than 720K, including my
Masters thesis and a couple papers.

FYI, the difference between 1.44 and 720K disks is much less than that
between 1.2 and 360K disks.  The coercivity of the media is as follows:

Disk Type      Coercivity (oersteds (sp?))

360K             300
720K             600
1.2 Meg          600
1.44 Meg         700


These are averages, whether you can use a 720K disk in the HD format
depends on the brand and perhaps even the batch.  Personally, I use an
'el cheapo' no-name brand, $15/box of ten, and as I've stated before,
only one out of fifty of these didn't work (couldn't write to one of the
last few sectors on the disk, but most of it was fine).

Regards, Davin
_______________leave_nothing_to_the_imagination_of_those_without_______________
GOAL:  To dance the light fan- |Davin Yap, Mechanical Engineering, U of Toronto
tastic in the face of derision,| yap@me.toronto.edu     yap@me.utoronto.bitnet
from those bland at heart.     |       ...{pyramid,uunet}!utai!utme!yap