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From: agm@cs.brown.edu (Axel Merk)
Newsgroups: comp.sys.next
Subject: Re: hard drive info wanted
Keywords: Hard disk add on's
Message-ID: <52489@brunix.UUCP>
Date: 9 Oct 90 01:08:40 GMT
References: <45139@apple.Apple.COM> <1990Sep25.234935.1501@watserv1.waterloo.edu> <51560@brunix.UUCP> <1990Oct1.044754.21637@watserv1.waterloo.edu> <52457@brunix.UUCP> <1990Oct8.214307.26670@ccng.waterloo.edu>
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Reply-To: agm@cs.brown.edu (Axel Merk)
Organization: Brown University Department of Computer Science
Lines: 41

In article <1990Oct8.214307.26670@ccng.waterloo.edu> tgoldtho@ccng.waterloo.edu (Thomas A. Goldthorpe) writes:
>In article <52457@brunix.UUCP> rca@cs.brown.edu (Ronald C.F. Antony) writes:
>>
>>There is no such thing as a 512/1024 byte sector 'problem'. Neither is
>>there a disktab 'problem'. Of course you should reformat your drive
>>
>
>The problem is simple.  Under 1.0 the disktab file only supports
>1024 byte blocks.  You will find this info right at the top of that
>file.  For 512 byte the simple fix is to specify that it is a
>1024 byte block and work on the rest of the entries under that
>assumption.  Very simple, allows any drive to be entered (seems to
>me the last time I saw TheFormatter it only supported one type of
>drive, it may now be enhanced, I don't know that part).  I've done
>this myself on a machine which now has 2GBytes of disk on it, I
>therefore KNOW it works, and all I had to do is modify disktab
>and use 'disk' to lay out the file system.  As far as low level
>formatting goes, I mentioned what to do weeks ago.  Now do me
>a favor and stop arguing over the news.  I post my method because
>it works, you post yours for the same reason.  
>
>Tom
This is not a simple *fix* - it lets your drive run, that's all.
Nothing is fixed, however: the drive is still formatted at 512 bytes
per sector. At the top-level, two 512 byte-blocks are bundled
together.
In other words: 
- you lose speed by bundling and because 512 bytes/sector is not the
fastest way to access data for the big drives.
- you lose space by using 512 bytes/sector (a lot more information
needs to be stored to keep twice as many sectors).

Don't tell me, they are equivalent, please - at a 1GB drive, you lose
about 50MB of disk space and 15-25% speed.

Yes, it works, but the low-level format is a lot more efficient.

Axel

P.s. TheFormatter works for WrenV, WrenVI, WrenVII. Other Wren drives
are on their way, so are Maxtor drives.