ali@rocky.STANFORD.EDU (Ali Ozer) (07/08/87)
[Initialization Failed!] A friend of mine came running into the microcomputer lab this morning, holding a 2.0 Meg 3.5" IBM disk. He said he needed to copy some stuff off the Macs. So he plugged the disk into a MacPlus, and then told it to initialize the disk as two-sided (800K). Well, the MacPlus sat there for about a minute, and then said "Initialization Failed!" So we tried again, and the same response! (Now this MacPlus can initialize normal DSDD disks, so there's nothing wrong with the machine.) So I told my friend, "the Amiga can initialize that." He said "oh, yeah, right --- if the Amiga can initialize this disk I'll give it you." We plugged the disk into the Amiga, typed "format," and after a minute of heavy grinding (this is a real old Amiga, you see, with Nov 1985 disk drives) the disk was initialized... I even put some files on it to prove to my friend that it works... Anyway, now I have a 2.0 Meg capacity floppy disk. 8-) Ali Ozer, ali@rocky.stanford.edu
keithd@cadovax.UUCP (Keith Doyle) (07/11/87)
In article <398@rocky.STANFORD.EDU> ali@rocky.stanford.edu (Ali Ozer) writes: >Anyway, now I have a 2.0 Meg capacity floppy disk. 8-) Well, if 2.0M 3.5" floppys achieve their high density in the same way HD 5.25" floppys do, you might not want to use it. HD disk drives use a higher write current, because the floppy media is less sensitive, which for some reason permits higher density. Normal disk drives will not put out a high enough write current to write the media reliably. I remember having all kinds of problems trying to format HD disks on non-HD drives until this was explained to me, and I gave up trying. Keith Doyle # {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd # cadovax!keithd@ucla-locus.arpa Contel Business Systems 213-323-8170 "Enter at your own risk"
hah@isum.intel.com (Hans Hansen) (07/12/87)
In article <1649@cadovax.UUCP> keithd@cadovax.UUCP (Keith Doyle) writes: >In article <398@rocky.STANFORD.EDU> ali@rocky.stanford.edu (Ali Ozer) writes: >>Anyway, now I have a 2.0 Meg capacity floppy disk. 8-) > >Well, if 2.0M 3.5" floppys achieve their high density in the same way >HD 5.25" floppys do, you might not want to use it. HD disk drives use >a higher write current, because the floppy media is less sensitive, which >for some reason permits higher density. Normal disk drives will not >put out a high enough write current to write the media reliably. I >remember having all kinds of problems trying to format HD disks on >non-HD drives until this was explained to me, and I gave up trying. > The new HI-Density Disks use PERPENDICULAR rather than PARALLEL magnetic particle alignment. The 2Meg floppy doubles the track count or has 160 cylendars. Upgrading the A1000 with a 2Meg drive while sounding neet and deliver more bytes for the buck, unless commodore gets on the band wagon (HINT HINT), will cause a compatibility nightmare. What I would like to see is a driver that can recognise both types of drives and automatically adjust the cylendar count. Hans
dragon@oliveb.UUCP (Give me a quarter or I'll touch you) (07/13/87)
in article <873@omepd>, hah@isum.intel.com (Hans Hansen) says: > In article <1649@cadovax.UUCP> keithd@cadovax.UUCP (Keith Doyle) writes: >>In article <398@rocky.STANFORD.EDU> ali@rocky.stanford.edu (Ali Ozer) writes: >>>Anyway, now I have a 2.0 Meg capacity floppy disk. 8-) >>Well, if 2.0M 3.5" floppys achieve their high density in the same way >>HD 5.25" floppys do, you might not want to use it. HD disk drives use ^^^ This is right. The 2.0mb 3.5" uses a higher transfer rate to achieve 18 sectors per track instead of nine, when used with MS-DOS. > The new HI-Density Dis
grr@cbmvax.UUCP (George Robbins) (07/15/87)
In article <873@omepd> hah@isum.UUCP (Hans Hansen) writes: > In article <1649@cadovax.UUCP> keithd@cadovax.UUCP (Keith Doyle) writes: > >In article <398@rocky.STANFORD.EDU> ali@rocky.stanford.edu (Ali Ozer) writes: > >>Anyway, now I have a 2.0 Meg capacity floppy disk. 8-) > > > >Well, if 2.0M 3.5" floppys achieve their high density in the same way > >HD 5.25" floppys do, you might not want to use it. HD disk drives use > >a higher write current, because the floppy media is less sensitive, which > >for some reason permits higher density. Normal disk drives will not > >put out a high enough write current to write the media reliably. I > >remember having all kinds of problems trying to format HD disks on > >non-HD drives until this was explained to me, and I gave up trying. > > > The new HI-Density Disks use PERPENDICULAR rather than PARALLEL magnetic > particle alignment. The 2Meg floppy doubles the track count or has 160 > cylendars. Upgrading the A1000 with a 2Meg drive while sounding neet > and deliver more bytes for the buck, unless commodore gets on the band > wagon (HINT HINT), will cause a compatibility nightmare. What I would > like to see is a driver that can recognise both types of drives and > automatically adjust the cylendar count. > > Hans Oh, confusion! 8-( The new 1.44 MB drives used on the IBM PS/2 machines don't use perpendicular recording, this is still pretty much off in the future. They don't have more tracks, rather they do use the 500KB/s data rate like the 8" floppies and AT 1.2 MB drives to increase the bit density on a track and get more sectors/track. They do require special hi-density diskettes, which have a higher magnetic coercivty, meaning they need a stronger magnetic field for writing/erasure, but can, in effect, support writing "smaller" bits on the disk. In any case, the floppy controller section of the Amiga chipset does not currently support a 500KB/s data rate in MFM mode, making the issue kind of academic at this point. You might be able to accomplish something in the "Apple GCR" mode, but as I understand it, there is considerably more software bit manipulation in the read/write process that would probably make this less attractive. -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)