Subject: Re: CD Writer Software
To: None <current-users@NetBSD.ORG>
From: Greg Earle <earle@isolar.Tujunga.CA.US>
List: current-users
Date: 04/19/1996 12:15:31
Peter Galbavy writes:
> The second level of software is that used to actually copy the image to
> a CD-ROM drive.  On a machie with a quiet SCSI bus and not much happeneing,
> with an older drive, you may find dd actually works.  Not tried it.  On newer
> drives with larger write buffers and restartable sessions etc. "dd" should
> work (at least once).  When you start getting complicated like mutil session
> and restartable sessions then I guess you need something a little more
> complex.
> I am pretty sure a couple of people on this list have direct experience here.
> What do you guys say ?

Well, in my primary life I work for the Multimission Image Processing Lab
at JPL.  Needless to say, we are drowning in CD-ROMs full of images, whether
created elsewhere or on CD-WO's made ourselves.

We often use "mkisofs" as Peter mentioned to create the HSFS images.  We also
use another software package from our CD-WO vendor

To actually *write* the CD-WO discs, we would never trust the host processor.
So we use a product called CD Studio from Young Minds, Inc. for this part.
Basically, it's a dedicated PC that has a built-in 4x CD-WO drive (used to be
an outboard Kodak 2x writer attached on a separate SCSI bus to the PC, but hey
the technology's gotten better and smaller).  It presents itself as a tape
drive interface to the host via the SCSI bus.  So we attach these things to a
few SunOS 4.1.3 machines, and then we just use "dd" to write 32k fixed-size
blocks to this pseudo tape dev: "dd if=mkisofsimagefile of=/dev/rst0 obs=32k".
That gets the data onto a 1 Gb hard drive inside the PC.  To make it actually
do the write, you merely issue an "mt -f /dev/rst0 fsf" which seems "odd" but
I guess it's the closest paradigm they could come up with.  Since the PC is
doing nothing but running this writer software, it can thus write to the CD-WO
at fixed speed.  Works like a champ.  Unfortunately, the setup (PC and CD-WO
and software) is a bit pricey.  But it's vital for a production environment
like ours where people are pressing CD-WO's all the time.  (We also use
things like 900 CD jukeboxes and the like ... )

Anyway, the bottom line is, use "mkisofs" under NetBSD to generate your HSFS
images, but I'd never trust trying to write the image out to a writer directly
under NetBSD (or VMS, or ... ).  The dedicated PC scheme works for us and it
guarantees constant head velocity during the writes so there's no glitches.

	- Greg