Path: utzoo!utgpu!attcan!uunet!jetson!john
From: john@jetson.UPMA.MD.US (John Owens)
Newsgroups: comp.unix.xenix
Subject: Re: Disk fragmentation
Keywords: fragmentation
Message-ID: <135@jetson.UPMA.MD.US>
Date: 2 Sep 88 21:09:53 GMT
References: <116@telmail.UUCP>
Organization: SMART HOUSE Limited Partnership
Lines: 22

In article <116@telmail.UUCP>, root@telmail.UUCP (Super user) writes:
> Such a defragmentation option is not available on SCO XENIX/386.
If you want to reorder your filesystem, dump, mkfs, and restore.

> Can fragmentation cause severe performance degradation on SCO XENIX?
I suppose it could impact performance if it got really bad; it all
depends on the seek time of your drive and the number of buffers you
have allocated.

> I ask this specifically for SCO XENIX because in the (kernel) 'configure'
> program there is an entry called 'disk block sorting'. Does that have
> anything to do with fragmentation?

No.  If this is the same disk block sorting in "real" UNIX, it sorts
pending I/O requests to do them in an optimal order.  In other words,
if there were pending writes for blocks on cylinders 482, 12, and 216,
and the last I/O was at cylinder 20, it would do the writes in the
order 12, 216, then 482 (hopefully).

-- 
John Owens		john@jetson.UPMA.MD.US		uunet!jetson!john
+1 301 249 6000		john%jetson.uucp@uunet.uu.net