Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!brutus.cs.uiuc.edu!uakari.primate.wisc.edu!aplcen!haven!mimsy!chris From: chris@mimsy.umd.edu (Chris Torek) Newsgroups: comp.unix.wizards Subject: Re: Raw disk I/O Message-ID: <22552@mimsy.umd.edu> Date: 15 Feb 90 14:59:37 GMT References: Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 25 In article marc@focsys.uucp (Marc H. Morin) writes: >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. These are not `BSD systems' so much as `systems whose original source was 4BSD'. Both Sony and MIPS have made substantial changes to parts of the kernel, some of which will affect raw I/O (raw I/O is tied into the VM system, for instance). >1) Does file locking via fcntl() still apply ? No, because there are no files. fcntl() does not do file locking in BSD anyway: fnctl() for locking is a System V feature. BSD provides only flock(). >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 ? No. ECC and bad sector replacements are handled by the disk driver (or by a software layer either above or within the driver, but in any case, below the `raw I/O' level). -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris