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From: magnar@sfd.uit.no (Magnar Antonsen)
Newsgroups: comp.sys.hp
Subject: Disk performance HP-UX 6.5
Message-ID: <2437@ifi.uio.no>
Date: 8 Dec 89 11:27:18 GMT
References: <3936@helios.TAMU.EDU> <770015@hpsad.HP.COM>
Sender: news@ifi.uio.no
Reply-To: magnar@sfd.uit.no (Magnar Antonsen)
Organization: University of Tromsoe, Norway
Lines: 25


While testing the CDC Wren IV disk some dramatic differences between HP and SUN
turned up.  Running the dd command illustrates the point. We reads 2000 blocks
of 8K size from the disk with the command

     dd if=/dev/<block-special> of=/dev/null bs=8k count=2000

and the time (measured with /bin/time) it takes do this is   

Sun 3/80 with SunOS 4.03    real:  18.4   sys: 8.2
HP 9000/370 with HP-UX 6.5  real: 144.8   sys: 9.1.

The same physical disk was used on both computers. The interface on the HP is
2.7 MB synchronous SCSI. Other tests (e.g. omitting the dd command, other block
sizes) gives the same conclusion: Sun is 7 to 9 times faster than HP.

Could anyone comment on or explain this difference in performance? A first
conclusion of our tests shows that the answer may be found in differences
between the device drivers in HP-UX 6.5 and SunOs 4.03.


//// Magnar Antonsen                   // N-9001 TROMSOE, NORWAY              /
/// Computer Science Department       // Phone : + 47 83 44043               //
// University of Tromsoe             // Telefax: + 47 83 55418              ///
/ NORWAY                            // Email: magnar@sfd.uit.no            ////