Path: utzoo!attcan!uunet!convex!killer!vector!rpp386!jfh
From: jfh@rpp386.Dallas.TX.US (The Beach Bum)
Newsgroups: comp.unix.xenix
Subject: Re: Line Printers and Kernel
Summary: line printer update and buffer stuff.
Message-ID: <7351@rpp386.Dallas.TX.US>
Date: 30 Sep 88 23:04:25 GMT
References: <644@quando.UUCP>
Reply-To: jfh@rpp386.Dallas.TX.US (The Beach Bum)
Organization: River Parishes Programming, Dallas TX
Lines: 36

In article <644@quando.UUCP> wichert@quando.UUCP (Peter Wichert) writes:
>
>
>Hi folks !
>
>We're using SCO Xenix 2.2 with parallel line printers .
>There are two things we don't understand:
>
>1.	The problem which occured is that the printer would not work as fast
>	as possible .

there are update kits available for slow line printers.  the problem has
several causes.  i suggest you get the updates for parallel printers from
SCO.  then, if that doesn't fix it, there is a polling parallel driver
out there someplace.  use it instead.

>2.	What is the standard number of NBUF and SABUF ?

NBUF should be about 10% of your physical memory.  for a 2MB machine, i
have NBUF == 302 and SABUF = 30.  i don't have to have any SABUFs but
configure put them in anyhow.

>	AND: what are SABUFs ??

system addressable buffers.  these buffers are addressable from the kernels
data segment and don't need to have the MMU changed to be addressed.  the
386 can address all of physical memory, whereas the 286 can't.  so, CPUs
which can't address their entire physical address space need to have some
SABUFs.  i've seen all manner of guidelines, but in general i suggest having
as many SABUFs as your kernel data segment will hold.  they are much faster
than far buffers.
-- 
John F. Haugh II (jfh@rpp386.Dallas.TX.US)                   HASA, "S" Division

      "Why waste negative entropy on comments, when you could use the same
                   entropy to create bugs instead?" -- Steve Elias