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From: mollers.pad@nixpbe.uucp (Moellers)
Newsgroups: comp.os.cpm
Subject: Re: floppy drive hardware
Message-ID: <1682@nixpbe.UUCP>
Date: 7 May 90 14:06:44 GMT
References: <9DD0D3D47EDF602A04@uwplatt.edu>
Sender: news@nixpbe.UUCP
Lines: 38

UCSLCT@UWPLATT.EDU (LANCE TAGLIAPIETRA) writes:

>Hello,
> 
>I just finished reading an informative article in The Computer Journal
>Issue 44: Mysteries of PC Floppy Disks Revealed by Richard Rodman.
> 
>I had always wondered how 1.2M and 1.44 Meg storage was achieved on
>5.25 and 3.5 inch hardware.  I am glad to see an article covering this
>territory.
> 
>The article did bring a couple questions to mind:
> 
>(1) What is the difference between 720K and 1.44M 3.5 inch drives.

The 1.44M drive has twice the bit-density of the 720K disks.
I.e. both have 80 tracks/side but the 1.44M drive has twice the number
of bits (and therefore bytes and sectors) per track.

>(2) What is the pinout for 3.5in drives. (a pinout for 5.25in is given)

As far as I know, they are the same (I use both drives on the same
flat-cable, the 5.25" connected with the usual edge-connector, the 3.5"
connected with a berg-type connector.
HOWEVER: there are drives that can use some of the pins for more than
one purpose (e.g. drive ready vs. disk change, something else vs. high
density etc).

>Can anyone shed light on this?

Hope this did!

>Lance Tagliapietra (ucslct@uwplatt.edu) or (ucslct@uwplatt.bitnet)

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