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
worthwhile.
der Mouse
mouse@collatz.mcrcim.mcgill.edu