From owner-freebsd-hackers Wed Jun 7 16:56:38 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id QAA23180 for hackers-outgoing; Wed, 7 Jun 1995 16:56:38 -0700 Received: from irz301.inf.tu-dresden.de (irz301.inf.tu-dresden.de [141.76.1.11]) by freefall.cdrom.com (8.6.10/8.6.6) with SMTP id QAA23171 for ; Wed, 7 Jun 1995 16:56:36 -0700 Received: from sax.sax.de by irz301.inf.tu-dresden.de with SMTP (5.67b+/DEC-Ultrix/4.3) id AA23748; Thu, 8 Jun 1995 01:56:32 +0200 Received: by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id BAA05159 for freebsd-hackers@freebsd.org; Thu, 8 Jun 1995 01:56:32 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.6.11/8.6.9) id BAA13215 for freebsd-hackers@freebsd.org; Thu, 8 Jun 1995 01:35:33 +0200 From: J Wunsch Message-Id: <199506072335.BAA13215@uriah.heep.sax.de> Subject: Re: silo overflows To: freebsd-hackers@freebsd.org (FreeBSD hackers) Date: Thu, 8 Jun 1995 01:35:32 +0200 (MET DST) Reply-To: freebsd-hackers@freebsd.org (FreeBSD hackers) In-Reply-To: <9506072244.AA21412@borg.ess.harris.com> from "James Leppek" at Jun 7, 95 06:44:06 pm Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) X-Phone: +49-351-2012 669 X-Mailer: ELM [version 2.4 PL23] Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Content-Length: 1249 Sender: hackers-owner@freebsd.org Precedence: bulk As James Leppek wrote: > > The floppy is not on the adaptec, only a little used drive and an > exabyte tape drive for backups (which were not being dome). > > Adaptec's 154X controllers are the most `famous' bus hogs. They do > > also cause all sort of troubles with floppy DMA operations ... Actually, it's totally unimportant whether you're using Adaptec's floppy controller or not. The problem is that the AHA-154X SCSI(!) controllers tend to hog the bus for too long, and an HD floppy controller needs to be serviced once each 16 µs. If this time expires, the FDC will abort the operation on the currently transferred sector. One could easily argue that the current fd driver handles this condit- ion very ungracefully (wasting a whole revolution to retransfer the sector in question), but i've got more important things on the plate regarding the floppy controller than improving support for braindead Adaptecs. (Once i've been replacing my Adaptec by an Bt 742A, the problem magically disappeared.) (No offense intended. Apologies to everybody who's thinking this would sound too rude. :) -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ Never trust an operating system you don't have sources for. ;-)