> Does anyone know whether you can do short incremental writes to the
> recordable CDROMs using a CDROM Writer Drive?
No, CDROM writing is 'session' based, ie. each time you'll need to write
a new session, with fresh directory structures etc. Not the kind of
thing you want to use to write small bits of data to unless you can cache it
to allow bursts. And I don't think you can cat to it as a raw device as
CD writing is time sensitive.
The main Q is: why do you want to use a CD writer for it? If you want a
read-only log of data it is easier (and possibly cheaper) to just get an
optical drive from, say, Panasonic and stick WORM cartridges in it. And
a double sided cartridge takes about 900MB of data in total.
> The writable (write once) CDROM drive could be attached to a a DOS or
> Windows PC and write what it read from a serial line attached to the
> logging firewall machine.
As long as you do it as a small number of files. DOS's FAT has got a
performance problem when the amount of files gets too big, I've had times
over 30 seconds to write a 2k file on a directory with about 900 small
files in (I'm talking about the WORM drive here). Provided you keep
the dust out of it I have found those drives impressively reliable, and
if there is trouble writing the data you'll get advance warnings as the
error correction will start flagging that it has to work.
> Or do you have to write an entire disk image to the CDROM at one time?
Well, you *can* split it into a few small sessions, but there is a
limit on the amount of session permitted on a single CDROM.
So, I'd use WORMs to log this (and if you use a multi-function drive you
can trial it with Read-Write cartridges before you commision it).
Regards, /// Peter ///
"You go to heaven... God sneezes... What do you say ?"