Path: utzoo!mnetor!uunet!cbmvax!grr
From: grr@cbmvax.UUCP (George Robbins)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga 2000 HD Situation
Message-ID: <3030@cbmvax.UUCP>
Date: 27 Dec 87 23:54:39 GMT
References: <2855@sdsu.UUCP> <4397@watdragon.waterloo.edu> <2861@sdsu.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 34
Keywords: hard disks spam

In article <2861@sdsu.UUCP> uzun@sdsu.UUCP (william uzun) writes:
> > Note that on page 24 of the 2090 user's guide it indicates that
> > you are allowed to soft select ANY interleave via an entry in the 
> > MountList.  In fact, they suggest a value of 0 (meaning 1:1).
> > 
> That figures, all of the 3rd party drive manufacturers assured me you 
> were limited to 3:1 or 5:1 interleave with the CA 2090 and the current
> FS, oh well like I said it is still my belief that the Supra Drive will
> be noticeably faster, and I'll report as soon as they send me one on the
> results.  An SDPI it isn't but I hope it gives me some speed advantage!

Interleave comes in two flavors.  One is where the controller can't do
multi-sector transfers if the sectors are contiguous and the other is
where you try to adjust the interleave so that when software requests
sequential block transfers, the next block is about to appear at the
read-write head.

The Commodore controller *does not* suffer from the first problem, unlike
some of the PC type controllers. The second issue is basically a matter
of tuning, and probably doesn't make a whole lot of differece with the
current file system.

Controllers that offer intelligent cacheing of the filesystem data such
as promised by ASDG may offer major perforance gains over the Commodore
controller with the current file system, however this advantage will
probably decline somewhat with a better filesystem.  Controllers that
provide simple track buffering may offer some improvment now, but may
or may not pay off in the future, depending on whether the software
does it's own track buffering.

-- 
George Robbins - now working for,	uucp: {uunet|ihnp4|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)