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From: hsu@eneevax.UUCP (Dave Hsu)
Newsgroups: net.micro.apple
Subject: Re: Apple 2 disks
Message-ID: <67@eneevax.UUCP>
Date: Sun, 3-Aug-86 14:05:29 EDT
Article-I.D.: eneevax.67
Posted: Sun Aug  3 14:05:29 1986
Date-Received: Mon, 4-Aug-86 01:32:16 EDT
References: <283@ski.UUCP> <175@uvicctr.UUCP> <2245@brl-smoke.ARPA> <3184@utcsri.UUCP> <943@rti-sel.UUCP> <569@bnrmtv.UUCP>
Reply-To: hsu@eneevax.UUCP (Dave Hsu)
Organization: Imperial Widget Research Center, Kingdom of Maryland
Lines: 41

In article <569@bnrmtv.UUCP> timlee@bnrmtv.UUCP (Timothy Lee) writes:
>> An Apple ][ with software disk control will beat a
>>    Radio Shack model II (w/controller) hands down in disk performance.
>> 
>>    * Faster track to track seek time.
>>    * Higher density.
>>    * Fast transfer times.
>     * Much better reliability !!!
>       Early RSTRS80M2 disk drives came up with error nearly 1 out of 8
>       times with premium disks (with cheapo disks, 1 out of 4).  This
>       required the addition of an `external data separator' (whatever).
>       One issue of Byte tells you how to build one, and many issues of
>       Byte had ads trying to sell `external data separators'.

Two reasons:
1) the old full-height SA350's were, in my book, some of the best drives
   ever made.  Sure, just about everybody else outperformed them in
   storage, or speed, or something, but when was the last time you had
   to do a head alignment?  The only adjustment that they ever needed
   was along the lines of calibrating the motor speed.
2) Another testimony to the design of the (bare-bones) 3470 floppy
   read-write chip.  Of course, Western Digital was more concerned with
   other controller features.

>> 
>> Also you can operate the disk spinning backward, or lay down spiral sectors.
>
>How do you spin the disk backward, other than turning it upside down?  Note

Yeah, how DO you spin the disk backwards?  I mean, without swapping the
polarity of the motor's power connector?

-dave
-- 
David Hsu  (301) 454-1433 || -8798 || -8715	"I know no-thing!" -eneevax
Communications & Signal Processing Laboratory	/ EE Systems Staff
Systems Research Center, Bldg 093		/ Engineering Computer Facility
The University of Maryland   -~-   College Park, MD 20742
ARPA: hsu@eneevax.umd.edu    UUCP: [seismo,allegra,rlgvax]!umcp-cs!eneevax!hsu

"Get back in the cupboard, you pantomimetic regal person..."