Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!rpi!crdgw1!ge-dab!peora!tarpit!bilver!bill
From: bill@bilver.UUCP (Bill Vermillion)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Formatting 1.2 Meg disks to 360K question
Keywords: floppy formatting
Message-ID: <443@bilver.UUCP>
Date: 16 Jan 90 04:21:22 GMT
References: <3226@ucrmath.UCR.EDU> <7715@nigel.udel.EDU> <1700@rodan.acs.syr.edu> <10280@saturn.ucsc.edu>
Reply-To: bill@bilver.UUCP (Bill Vermillion)
Organization: W. J. Vermillion, Winter Park, FL
Lines: 27

In article <10280@saturn.ucsc.edu> ted@helios.ucsc.edu (Ted Cantrall) writes:
>In article <1700@rodan.acs.syr.edu> amichiel@rodan.acs.syr.edu (Michielsen) writes:
>>
>>If you hold a real 1.2 MB disk up to the light and look at it at about a 30
>>or 45 degree angle, you should be able to see a ring. In the read/write window
>>at the outside edge of the floppy disk media. It's about .1 inch wide or so.
>----
>Have you checked several brands of disks? The brand of 1.2M disks we use have 
>no trace of that "ring". And besides, how would the older technology of
>360K know to look for a ring that was invented later??
>				-ted-

The rings were designed to prevent the center of the disk from being chewed up
by the hub rings.  The original 5.25 drive design clamped the disk when the
door was shut.  An improperly centered diskette could have the edges of the
center hole crimped.  Later designs went to a steeper cone.

When the 1.2 meg drives came out, they were all of the later technology.  They
rotated the drive when the diskette was inserted and automatically centered
the diskette on the clamp ring.  The HD diskettes don't need the
re-inforcments, and while many of the 360s did, they really don't anymore
unless you are using one of the old full-height 5.25" drives.


-- 
Bill Vermillion - UUCP: {uiucuxc,hoptoad,petsd}!peora!tarpit!bilver!bill
                      : bill@bilver.UUCP