Subject: Re: I am booting from the disk, but...
To: None <port-sun3@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: port-sun3
Date: 01/09/1996 14:19:22
> I was using a CDC 94161-155 FH drive [...].  The documentation for
> the drive, found in Seagate's ftp site, claims the drive has 155MB
> formatted capacity.  [...]  I eventually began paying attention to
> the boot messages.  One of those claimed the drive to be 148MB
> instead of 155.  So, just for the fun of it, I repartitioned it using
> that value.  Guess what?  It worked!

> Moral of the story:  the 3/50 seems to know about hard drives better
> than their manufacturers.  Go figure. :P

More likely CDC says it's 155MB, meaning 155*10^6 bytes, and NetBSD
says it's 148MB, meaning it's 148*2^20 bytes.  This is a standard trick
of disk manufacturers, to quote sizes in million-byte megabytes instead
of real megabytes (it's a cheap way of inflating their drive sizes by
about 5%, or 7.4% if they use GB instead of MB).  For example, I've got
one of those zip drives from iomega, and it says 100 megs per disk;
they're actually 96 megs - which is just marginally over 100 million
bytes.  In your case, I just worked it out: 148MB is 155189248 bytes,
which is probably where CDC got their 155MB lie.

I'm vaguely surprised nobody has yet slapped disk makers with a
misleading-advertising suit over this.  Probably nobody's thought it

					der Mouse