From: utzoo!decvax!cca!dan2@BBN-UNIX@sri-unix
Newsgroups: net.unix-wizards
Title: Re: V6 to V7 conversion
Article-I.D.: sri-unix.2540
Posted: Sat Aug  7 18:38:05 1982
Received: Sun Aug  8 00:48:28 1982

From: Dan Franklin 
Date: 20 Jul 1982 12:52:39 EDT (Tuesday)
The reasons I know for continuing to divide disks into partitions
(usually two: a small one for the root, and /usr) are:

1. Efficiency. With inodes located at one end of the file system,
resolving a pathname requires repeatedly moving the head from one
end of the file system to the other as first an inode, then a series
of directory blocks, then another inode, etc. are read in. Having
several smaller filesystems minimizes the total head movement and hence
the time it takes. (This reason goes away with the 4.2BSD filesystem
organization.)

2. Protection. Should something horrible happen to part of the disk,
it would be nice if it only incapacitated the root (which is small
and can be brought back quickly; also doesn't change as often as /usr,
so going to the morning's dump is unlikely to bother anyone) or if it
only broke /usr (which lets you use all the programs on the root to find
and fix the problems with /usr). "Something horrible" can also include
running out of space; it's nice when running out of space on /usr doesn't
stop system programs using the root (or using pipes) from working.