home *** CD-ROM | disk | FTP | other *** search
- Xref: sparky comp.arch:10507 comp.unix.bsd:8576 comp.os.linux:15979
- Newsgroups: comp.arch,comp.unix.bsd,comp.os.linux
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!usc!cs.utexas.edu!sun-barr!sh.wide!kogwy!math-keio!mad
- From: mad@math.keio.ac.jp (MAEDA Atusi)
- Subject: Re: IDE faster than Mips SCSI disk
- In-Reply-To: eoahmad@ntuix.ntu.ac.sg's message of Fri, 6 Nov 1992 03: 39:42 GMT
- Message-ID: <MAD.92Nov7220823@amber.math.keio.ac.jp>
- Lines: 54
- Sender: news@math.keio.ac.jp
- Nntp-Posting-Host: amber
- Reply-To: mad@math.keio.ac.jp
- Organization: Faculty of Sci. and Tech., Keio Univ., Yokohama, Japan.
- References: <1992Nov6.033942.21194@ntuix.ntu.ac.sg>
- Date: Sat, 7 Nov 1992 13:08:26 GMT
-
- In article <1992Nov6.033942.21194@ntuix.ntu.ac.sg> eoahmad@ntuix.ntu.ac.sg (Othman Ahmad) writes:
-
- > 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.
-
- You may be right. But unfortunately, bare speed of hard disk drives
- around is not so fast (typically < 2MB/sec) that can fill up the
- bandwidth. And, as Dan Hildebrand mentioned (in article
- <7j+q=2d@quantum.on.ca>), SCSI can do multiple transfer at the same
- time, as well as let CPU free from data transfer job and keep
- computing. You can't even perform seek on another IDE drive during
- IDE data transfer. It can make a difference under multi-tasking OS.
-
- >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
- [deleted]
- >IOZONE performance measurements:
- > 367586 bytes/second for writing the file
- > 499942 bytes/second for reading the file
-
- The PC result looks reasonable. But mips result seem to be too slow
- for SCSI-2 disks. Maybe because (as Phillip Fayers written in
- <13481.9211061131@thor.cf.ac.uk>) poor I/O performance of Ultrix. But
- I think larger buffer size (e.g. 8192 bytes) would be better for
- testing disk drive/interface performance, while smaller buffer size
- test can measure total I/O performance including OS/library overhead.
-
- On SparcStation1+ with SCSI drive, running SunOS 4.1.1, I get:
-
- 32M file, 512bytes buffer:
- IOZONE performance measurements:
- 204348 bytes/second for writing the file
- 556120 bytes/second for reading the file
-
- 32M file, 8192bytes buffer:
- IOZONE performance measurements:
- 653760 bytes/second for writing the file
- 1207012 bytes/second for reading the file
-
- Hmm... SunOs, too, seems to have significant overhead with small buffers.
- Is this figure mean ISA machine running 386bsd beats SparcStation1+ in I/O?
- PCs are widely believed to be "comparable to WS in CPU speed, but far
- more slower in I/O".
-
- I'm very interested in the result of EISA SCSI-2 with large file size
- & large buffer size, if it's available.
-
- ;;; Keio University
- ;;; Faculty of Science and Technology
- ;;; Department of Math
- ;;; MAEDA Atusi (In Japan we write our family names first.)
- ;;; mad@math.keio.ac.jp
-