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From: cmcmanis@sun.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: C-Ltd hard disk
Message-ID: <17256@sun.uucp>
Date: Thu, 23-Apr-87 15:46:01 EST
Article-I.D.: sun.17256
Posted: Thu Apr 23 15:46:01 1987
Date-Received: Sat, 25-Apr-87 08:05:29 EST
References: <411@pttesac.UUCP> <249@rocky.STANFORD.EDU> <1207@ulowell.cs.ulowell.edu>
Organization: Sun Microsystems, Inc. - Mtn View, CA
Lines: 43
Keywords: C-Ltd hard disk lockup video streaking troubles
Summary: Partition tradeoffs

In article <1207@ulowell.cs.ulowell.edu>, (Bob Page) writes:
> 
> I was talking to a guy who also has the CLtd 50M hard drive.  He said
> that although it came as one partition, he broke it into six 8M partitions
> which made it a lot faster (due to the smaller bitmaps that AmigaDOG
> has to wade through).  He suggested I partition my 20M drive into
> four 5M sections to increase the speed.
> 
> Has anyone done this?  Have you done any benchmarks before/after?
> 
> ..Bob

I talked to a guy from Supra who said they partitioned their drives
because on the Atari "you have to." Personally, I don't think he 
was very well informed nor do I think partitioning helps the 40
folder bug on the ST's. Anyway on one's Amiga there are no such
restrictions on how big a disk you want to add. Due to the hashed
directories searching for a file is relative only to the number of
files in a directory and the number of layers 'deep' it is. 

So partitioning your drive on an Amiga does make it faster but
not for the reason Bob mentions (ie bitmap size). There are actually
two ways that you win here. First, when there is a problem with the
drive and it has to be 'validated' it takes longer on a bigger drive
because it has to go look at *every* file on the disk. Fortunately,
if the driver that comes with your drive is correctly written then
it won't have to do that very often. The second feature is that 
AmigaDOS always maintains a few blockbuffers for each disk device.
This mini-cache which can be increased with the 'addbuffers' command
is local to the partition and therefore things like copies and some
directory reads can be greatly enhanced. 

I have a MicroBotics MAS-Drive and have run it as one partition,
two partitions, and three partitions. The multipartition case 
is a wee bit faster in some cases but I haven't noticed and 
major speedups. 


-- 
--Chuck McManis
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