Subject: Re: rewriting disklabel
To: David Brownlee <>
From: Frederick Bruckman <>
List: netbsd-users
Date: 05/09/1998 01:25:54
On Thu, 7 May 1998, David Brownlee wrote:

> 	Almost certainly nothing.
> 	The RPM entry can be use to optimise head movement, but is
> 	pretty much irrelevant for most NetBSD ports (it could still
> 	be useful for vax and hp300 for example).
> 		David/absolute
>      		  -=-  "cold nights, dark days..."  -=-
> On Tue, 5 May 1998, John B. Lee wrote:
> > Being new to BSD, I'm also new to disklabels. Just out of curiosity, what
> > would happen if I rewrote a disklabel to a disk, with only the rpm entry
> > changed? What does the rpm entry do anyways? Does the kernel use it in
> > some manner?

That's actually the "rotdelay" built into a filesystem. The RPM entry in
the kernel may be used by `newfs' when you invoke it without the `-d'
switch, or maybe not. You can change the rotdelay on the fly with
`tunefs', regardless. I have experimented with that on mac68k, but I can't
say that its led to any noticable difference in performance.