Subject: questions about fs layout and veracity of dd timings
To: None <current-users@NetBSD.ORG>
From: jason baker <>
List: current-users
Date: 03/16/1995 13:05:27
	I have an i386 with a fairly new 245 meg ide drive, and a full
height lxt-340 meg scsi.  I am considering adding a full height
quantum 105 from my old atari.  Right now, the ide drive holds dos and
/, while the 340 holds /usr  and some swap space.  My first thought
was to make the 105 /usr and the 340 /usr/src.  (I figure that if
binaries are kept seperate from everything else, paging text segments
should be faster.) 
	Today, I hooked up the 105 and played around with dd.  Running
dd ibs=65535 obs=65536 count=256 if=/dev/rxxxd of=/dev/null on either
the ide drive or the 340 will give 2097152 bytes/sec (my scsi
controller does pio), while on the 105 it complains about the lack of
a disklabel and gives 578524 bytes/sec.  Is the lack of a disklabel
slowing down every read or is the 105 really that slow?  I always
imagined that my big old drives where contemperaries and would have
similar performance.
	If the 105 is that slow, perhaps I could use it for /usr/src
and divide the 340 between /usr and /usr/local with /usr/local/bin
symlinked to /usr/.local.bin.  Or perhaps isolating pure text segments
is not as important as I think.  In any case, I am curious:  How big
is /usr/src on an i386 once everying has been built?

	thanks for any and all woderful advice,