need 720k 3 1/2" disks

From: jamesd <jdickens_at_ameritech.net>
Date: Mon Jun 9 23:36:00 2003

On Monday 09 June 2003 11:07 pm, Fred Cisin (XenoSoft) wrote:
> On Mon, 9 Jun 2003, jamesd wrote:
> > hi
> > To answer your question a true DSDD 3 1/2" drive can't read a DSHD,
> > because the media is differenent... so it can't read a disk formated in a
> > DSHD
>
my question was could a DSHD disk formated using 720k parameters on a DSDD
drive be readable on a DSDD drive was the question... i know a DSDD disk is
readaple and formatable on a DSHD drive it just that a DSHD drive can't be
fooled to write a usuable DSDD disk by covering the whole or any other
message... because the media on the DSHD disk is different..


> No, a "DSDD" can't read a DSHD because it is recorded at a higher density.
> WHICH IS NOT THE DIRECTION THAT WE HAVE BEEN TALKING ABOUT!
>
> The message that you just replied to was addressing the issue of whether
> the 720K diskette could be formatted in an ordinary PC (specifically XP).
>
> EVERY DSHD drive can read "DSDD" diskettes, so long as the disk controller
> supports the lower (250K) data transfer rate, and the correct
> software is present. That includes every disk controller that you have
> ever seen, although Tony and a few others may have some that were
> originally designed for 8" that do not support the lower rates.
>
> > drive... i can't even boot my laptop to test if the reverse is true.
> > By the way i also have an excepted an offer from a fellow list member to
> > send me disks... witch i really appreciate...
>
> NO manufacturer of a 3.5" HD drive has ever made an HD drive that
> couldn't ALSO handle the lower density.
>
> Yes, the media is different. The differences are: different chemical
> coating to produce a slightly higher coercivity, and an extra hole in
> the diskette to tell drives which diskette it is. Those are the ONLY
> differences. NOTE: not all drives include the sensor to notice the disk
> differences.
>
> THEREFORE: as stated previously, the ability to FORMAT 720K in a 1.4M is
> ONLY an issue of whether the SOFTWARE supports it, and if the harware is
> "normal".
Received on Mon Jun 09 2003 - 23:36:00 BST