Subject: Re: new positional i/o system calls
To: Jason Thorpe <>
From: Simon Burge <>
List: current-users
Date: 07/01/1998 10:20:49
On Tue, 30 Jun 1998 12:37:50 -0700  Jason Thorpe wrote:

> I have just added new positional I/O system calls, per XPG4.2, pread(2)
> and pwrite(2).  These are like read(2) and write(2) except they also
> take an absolute offset at which to begin the I/O.  They do not modify
> the file pointer.
> I also added preadv(2) and pwritev(2), like readv(2) and writev(2), but
> also taking a positional argument.
> SVR4 has had these for a while, and database applications like to use
> them because they eliminate 50% of the system calls for completely
> random access to a file.
> I'm going to change some of NetBSD's code to use the new system calls
> later today so that people will have some example usage, in addition
> to the manual page.

Without looking, is this something that the Berkeley DB routines and
libkvm could make good use of?