Xref: utzoo unix-pc.general:1542 comp.sys.att:4539
Path: utzoo!utgpu!water!watmath!uunet!lll-winken!killer!gtmvax!dms3b1!dave
From: dave@dms3b1.UUCP (Dave Hanna)
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: All right! and 1.2M floppies; HwNote05(is this where I say long?)
Summary: Can't get more than 10 sectors/track
Keywords: 3.5 inch drive
Message-ID: <154@dms3b1.UUCP>
Date: 20 Oct 88 22:35:10 GMT
References: <368@uncle.UUCP> <281@bagend.UUCP>
Reply-To: dave@dms3b1.UUCP (Dave Hanna)
Distribution: na
Organization: Daltech MicroSystems, Dallas
Lines: 35

In article <281@bagend.UUCP> jan@bagend.UUCP (Jan Isley) writes:
[ discussion of substituting 3.5 inch drive for 5.25 ,
and how to format for 800 sectors ]
>You may notice that these are just modified copies of /usr/bin/fdfmt??.??
>And while you are copying files, add these in /usr/lib/iv/FD????

>#-------------------
># /usr/lib/iv/FD35nl
># iv description for 3.5 inch 96 TPI Floppy file system disk w/o loader
>type		FD
>name		Floppy
>cylinders	80 <--- we changed this to 80!
>heads		2
>sectors		10 <--- why can't this be more than 10???
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>steprate	0  <--- we cannot change this anyway
>singledensity      <--- changing this is no help, to bad!

You can't have more than 10 sectors because that's all that will
fit on the drive, given data transfer rates (250K bits/second)
and rotational speeds (5 rps ), and the requirement for inter -
sector gaps to allow for instantaneous speed variations.

(Note: Amiga gets 11 sectors per track, but they do it by writing
entire tracks at a time, eliminating the requirement for intersector
gaps.  I think they also use gcr instead of MFM.)

>Jan Isley, follower of Zen, picker of nit	h(404) 434-1335

        Dave Hanna

-- 
Dave Hanna,  Daltech MicroSystems    |  "Do or do not -- There is no try"
P.O. Box 584, Bedford, TX 76095      |                        - Yoda
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