*BSD News Article 88510


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From: j@ida.interface-business.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc,comp.unix.bsd.misc
Subject: Re: Bulletproof UNIX CD Recording
Date: 4 Feb 1997 13:25:14 GMT
Organization: interface business GmbH, Dresden
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Message-ID: <5d7dbq$osb@innocence.interface-business.de>
References: <01bc11db$a38a6f80$c8ec0c26@cd001456.interramp.com>
Reply-To: joerg_wunsch@interface-business.de (Joerg Wunsch)
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To: roycew@mindspring.com
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:35110 comp.unix.bsd.misc:2318

"Royce White" <roycew@mindspring.com> wrote:

> This is a site that has a system for recording CDs in many UNIX
> flavors. It has a number of decent credentials. The system looks
> robust and easy to use.

Now since you're posting this in technically oriented newsgroups, and
i'm incidentally also the maintainer of FreeBSD's worm driver, let's
go into technical discussion.  First, a couple of quotes from your
Web Site.

: For network recording you don't need to dedicate a workstation for
: disc production. CD-Studio works in the background leaving your
: workstation free for other tasks. Plus, CD Studio is upgradeable and
: flexible. It's easily upgradeable to over 26 different platforms,
: including NT.

The list of supported platforms looks indeed impressive.  Sure,
FreeBSD ain't there.  (Why do you crosspost it to the FreeBSD group
then?  Did you verify the BSD/OS binary runs there?  BSD/OS binaries
in general run on FreeBSD, but i'm afraid the SCSI subsystems are too
different.)

: CD Studio grows as your recording needs grow. You can even record and
: label CDs unattended.

Hmm, but that's nothing brilliant, but something i would basically
just *expect* from software in a multitasking multiuser environment.
(What the heck should i attend there anyway? :)

But i would be more interested to learn about your multitasking
abilities and limitations.  Don't pretend there weren't any: we all
know that CD recorders need streaming data at at least N * M KB/s,
with M being ~ 155 for data recording, or 175 for audio recording, and
N being the ``speed multiplier'' (1, 2, 3).  So if the source of your
data is too slow for some reason (excessive seeks required on the
source disk, getting data over an overloaded network), your burner
simply starves.

So now, the question is when exactly it will fall over?  Also, on a
related note, how much memory uses your system as cache?  This cache
is required to be actual physical memory (won't make sense otherwise),
so the decision will be relevant to how much system memory is required
at least to successfully run the tool at all.

Just for comparision, here's the figures as i am running:

. i586/something machine, with 32 MB RAM,
. 2 x CD-R (Plasmon RF4102) with 2 MB internal cache,
. 5 MB userland cache to burn a CD-R.

The system, of course, runs full multiuser while burning in
background, including a load of X11 applications -- just my usual
desktop.  There are usually between 30 and 60 MB of data paged out
(thus of danger to be requested for pagein operations while the
recording is in progress).  Also, the machine occasionally performs
various CPU and VM intensive server operations like Ghostscript
printer filtering flawlessly.  (At this point, it fell over when being
equipped with only 16 MB, but still running X11.  That basically
demonstrates the limits.)

I haven't tried to create the CD image ``on the fly'' yet, and feed it
directly into the burner, although i'm fairly positive this should
work.

Can you tell us how your system compares to this (apart from a fancy
GUI to operate it, which my version is totally in lack of)?

(Mailed and posted, since i'm afraid you're not following the
newsgroups you're posting to.  You should, however, that's part of the
Usenet Netiquette.)

-- 
J"org Wunsch					       Unix support engineer
joerg_wunsch@interface-business.de       http://www.interface-business.de/~j