Date: Sun, 26 Nov 1995 15:15:13 +0200 (EET) From: "Andrew V. Stesin" <stesin@elvisti.kiev.ua> To: hardware@freebsd.org Cc: current@freebsd.org Subject: "Gold" writable CDs and FreeBSD -- opinions, comments? Message-ID: <199511261315.PAA20864@office.elvisti.kiev.ua>
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Hello people, especially famous SCSI, CDROM and filesystems experts!
This message is pretty long, I strongly apologize for taking your time.
Wouldn't you mind reading it and commenting my ideas a bit, please?
I think, that may be interesting not only for me personally, and I
really need your comments and opinions to help me to make a decision.
I'd appreciate any feedback, including "rotten potatoes"... :-)
Thanks in advanse!
I know there are some devices with SCSI interfaces for doing massive
backups with a great "bang-per-buck" -- namely WORMs and writable ("gold")
CD drives. I even used a writable-CD device some time ago, it had
some windo$e control utility. WORMs are rare today here, but writable-CD
devices are present on the market. (BTW this is a considerable investment,
not a simple $100, and each goldCD costs at least $15 here, so the reasons to
buy it must be strong. They are strong for us there even without
considering using it with FreeBSD, and a possibility of FreeBSD to work
with this device will increase the strength even more).
Using of writable "gold" CDs may be _very_ attractive. Not
for backups first of all (for the reasons that you usually need to have
a non-busy system to get writing process streaming without any
interrupts in data transfer between a disk and a writable device,
otherwise the goldCD will become damaged and unusable; so you need to
go single-user to be sure your'e Ok, this isn't too convenient for
everyday use. But nevertheless, you don't do such _massive_ backups
every single day? once a week or two; it seems to be acceptable)
Suppose you are creating a firewall router' custom configuration. You use
some small old SCSI disk for a) booting the kernel, b) reading
hand-tunable configuration from /etc, d) writing tempfiles & logs,
maybe swapping if needed. Everything else, all daemons, utilities,
will live on a hand-burned goldCD so even
if the host itself is compromised via the net, an intruder will
be _physically_ unable to leave any sugnificant hooks or Trojan horses in the
system for later reuse, and me, poor admin, won't need to worry
checking or reloading all the binary tree (even if comparatively small),
especially assuming that the box may be very far from me and physically
unaccessible. Some kind of super-smart hardware router with 650Mb of
flash ROM but a LOT cheaper and useable I think :-)
The same is true for any other, not only router, case when you want to be
_totally_ sure that nobody and nothing will change your carefully
customized and tuned configuration. Then, you get a possibility of making
cheap series of copies of your solution. And even more: you get
rid of any hard disk troubles or of any cases when actual admin of the system
occasionally changes /bin/cat permissions to suid root, thus tech
support is a lot easier. Opinions? I'm almost sure that people who
sell FreeBSD solutions will agree with me at least for some points.
What I want to ask is:
suppose I get such a device (a drive for writing "gold" CDs, with SCSI
interface). I'll be using it with windo$e from the very start, of course.
But what steps are required to get it working with FreeBSD? I think there are:
* ensure myself that it works nice in a usual RO CD mode.
* get a description of it's command interface used to initiate,
tune and perform writing. This may be difficult, though...
But suppose for now that I've already got one.
(?) Then a first dark spot comes up. What step will be the next?
I think that I'd need to examine existing drivers for
SCSI devices and to add some new functionality to a 'cd'
driver, yeah? This includes lazer tuning, calibration,
test-writing commands, "close record", etc.
* So, good, now I take some simplistic CDplayer program
without bells&whistles and make it work for writing.
* suppose I got it working and writing a stream of blocks of
needed length to a goldCD. Ok, we win!
Comments?
Or -- just another approach. Suppose I don't worry about support of CD write
operations for the goldCD at all (I'd get a windo$e utility at last,
damn it, but it works). I'm going to create a 650Mb file with ISO9660
FS inside it, write everything I want there, test it; then
transfer the whole 650Mb file to the windo$e box and burn it into
the goldCD there. Much less convenient in terms of disk usage,
but is this possible at all just now? (I've hear rumors that
writing is broken for ISO9660 FS).
Another aproach. If ISO9660 is really broken for writing, can I create
a "normal" Berkeley FFS filesystem in the file, burn it to the goldCD
and mount it later? I don't care that windo$e won't read this disk, really! :)
Anyway, will a mount command _without_ '-t cd9660' be possible for
a CD? What caveats one can expect here?
Thanks a lot for reading this and for your comments!
--
With best regards -- Andrew Stesin.
+380 (44) 2760188 +380 (44) 2713457 +380 (44) 2713560
An undocumented feature is a coding error.
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