Subject: NetBSD/i386 install bug
To: None <netbsd-bugs@NetBSD.ORG>
From: Jim Howard <firstname.lastname@example.org>
Date: 11/04/1995 13:13:47
There is a serious bug in the "install" script on the second installation
floppy for NetBSD/i386.
The problem is that no options are passed to newfs. As a result,
interleaved file systems are created, and real-world drive performance is
Running the original 1.0 asynchronous NCR driver, on a file system installed
over the middle third of a Micropolis 4110 1 GB hard drive, I got about 500
KB/sec file transfer rates. Patching in a more recent fast synchronous
version of the driver, this improved to 750 KB/sec. After editing the
"install" script to pass "-a 8 -d 0" to newfs and re-installing from
scratch, the numbers leaped to around 3 MB/sec.
Those file transfer rates were obtained with a read() call on ordinary but
large files, using gettimeofday() calls to obtain microsecond-resolution
timing across the read().
The more common practice of using "time dd" does not reveal the problem,
because dd reads sequential blocks, oblivious to the fact that each block in
turn belongs to a different file. So dd's numbers are bogus with respect to
perfomance obtained in normal use of the system.
--Jim Howard (email@example.com)