From owner-freebsd-hackers Tue Nov 28 04:53:23 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id EAA03546 for hackers-outgoing; Tue, 28 Nov 1995 04:53:23 -0800 Received: from hda.com (hda.com [199.232.40.182]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id EAA03540 for ; Tue, 28 Nov 1995 04:53:19 -0800 Received: (from dufault@localhost) by hda.com (8.6.11/8.6.9) id HAA08317; Tue, 28 Nov 1995 07:52:39 -0500 From: Peter Dufault Message-Id: <199511281252.HAA08317@hda.com> Subject: Re: Anyone keen to help me get a Phillips CDD 521 Recorder working? To: joerg_wunsch@uriah.heep.sax.de Date: Tue, 28 Nov 1995 07:52:38 -0500 (EST) Cc: freebsd-hackers@FreeBSD.ORG In-Reply-To: <199511272240.XAA07448@uriah.heep.sax.de> from "J Wunsch" at Nov 27, 95 11:40:05 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text Content-Length: 971 Sender: owner-hackers@FreeBSD.ORG Precedence: bulk > > > > I'll checkout rtprio, and I'm sorry I don't have all the specifics > > right now (you can probably find them at http://www.cdarchives.com) but > > the Yamaha is a 4X writer with only 512k buffer. > > 4times, 6times -- what's the base for the comparision? The unit is a single speed CDROM at 150K/s. So this 4X driver is 600K/s, so you have under a seconds data in the FIFO. (This makes more sense than the frame grabbers that I've seen advertised that operate at "twice real time".) > The SCSI bus itself can transfer about 8 MBytes/s continuously (on a > "standard" 8-bit controller, like the AHA-2940 or NCR 53c810). How > close do these burners come to that value? They hopefully burst into their RAM buffers at this speed to give you the latency you need to go read another chunk. -- Peter Dufault Real Time Machine Control and Simulation HD Associates, Inc. Voice: 508 433 6936 dufault@hda.com Fax: 508 433 5267