Path: utzoo!attcan!uunet!clyde.concordia.ca!jarvis.csri.toronto.edu!mailrus!iuvax!maytag!focsys!marc
From: marc@focsys.uucp (Marc H. Morin)
Newsgroups: comp.unix.wizards
Subject: Raw disk I/O
Message-ID: <MARC.90Feb14083116@focsys.uucp>
Date: 14 Feb 90 13:31:16 GMT
Sender: marc@focsys.uucp (Marc H. Morin)
Organization: Focus Automation Systems Inc. Waterloo, Ontario.
Lines: 22


I am investigating using the raw disk interface to increase performance
of our application. The application is an imaging system,  thus the I/O
consists of large data transfers to and from the disk.

I need to know a little more about the behaviour
of the raw disk driver (in general) for BSD systems.  If it helps, I am
particularly interested in SCSI drives on Sony and Mips workstations.

1) Does file locking via fcntl() still apply ?

2) I understand the disk is viewed as one single flat-file,  but does
   this also mean that I must handle bad sectors within my application ?

3) Any experiences that you might have had with raw disk I/O.


Thanks for your help

Marc H. Morin							Focus Automation Systems Inc.
watmath!focsys!marc						Waterloo, Ontario
										(519)746-4918