*BSD News Article 7499


Return to BSD News archive

Xref: sserve comp.arch:27923 comp.unix.bsd:7548 comp.os.linux:14973
Newsgroups: comp.arch,comp.unix.bsd,comp.os.linux
Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!zaphod.mps.ohio-state.edu!wupost!gumby!yale!yale.edu!jvnc.net!nuscc!ntuix!eoahmad
From: eoahmad@ntuix.ntu.ac.sg (Othman Ahmad)
Subject: IDE faster than Mips SCSI disk
Message-ID: <1992Nov6.033942.21194@ntuix.ntu.ac.sg>
Organization: Nanyang Technological University - Singapore
X-Newsreader: TIN [version 1.1 PL6]
Date: Fri, 6 Nov 1992 03:39:42 GMT
Lines: 55

These figures are not meant to be a thorough study. More of a provocation
for more soul searching. The widespread belief that SCSI-2 is "defininely
faster than IDE" is questionable, in fact under some circumstances, entirely
false.
	The results are not surprising for those who study the technical
specs of these disks. IDE has more potential for high speed because of its
lack of protocaol overhead. Its closeness to the disk also make it very
reliable and efficient.
	There are advanced disks which can do simultaneour multiple-head reads,
but these techniques can also be used for IDE as well.
	IDE is just a simple interface definition, just like SCSI-2, but IDE,
is optimised for HARD DISKS, SCSI is not. SCSI is more general purpose.

The mips machine under test runs on ultrix. Although it has up to 10Gbyte 
of hard-disk, it is not so heavily loaded. We only use it for email and
news feed. Fragmentation can be severe because I cannot even have 32 
megabyte free space in /usr/tmp , only 30 Mbytes.

	IOZONE: Performance Test of Sequential File I/O  --  V1.14b (1/31/92)
		By Bill Norcott

	Operating System: ULTRIX

	Send comments to:	norcott_bill@tandem.com

	IOZONE writes a 30 Megabyte sequential file consisting of
	61440 records which are each 512 bytes in length.
	It then reads the file.  It prints the bytes-per-second
	rate at which the computer can read and write files.


Writing the 30 Megabyte file, 'iozone.tmp'...91.000000 seconds
Reading the file...49.000000 seconds

IOZONE performance measurements:
	345684 bytes/second for writing the file
	641985 bytes/second for reading the file
****************************************************************************
This PC machine runs on 386bsd. Using 1 megabyte test file it is faster than
a similar 486/50Mhz EISA SCSI-2 hard-disk.

486/33 Maxtor 7120 200Mbyte

Writing the 32 Megabyte file, 'iozone.tmp'...91.283333 seconds
Reading the file...67.116667 seconds

IOZONE performance measurements:
	367586 bytes/second for writing the file
	499942 bytes/second for reading the file
--
Othman bin Ahmad, School of EEE,
Nanyang Technological University, Singapore 2263.
Internet Email: eoahmad@ntuix.ntu.ac.sg
Bitnet Email: eoahmad@ntuvax.bitnet