[debian-knoppix] Re: [CLUE-Tech] Burning Knoppix ISO with XCDroast?

[Klaus Knopper]

On Sun, Mar 09, 2003 at 11:13:59AM -0700, Dave Price wrote:
> Joe,
> 
> This one liner in my ~/bin directory works great - i think you do not
> really nead su - but the permissions are not too portable across distros
> - my script is called 'burn' just type burn, the first few chars of the
>   .iso followed by a tab, and get your felt pen ready.
> 
> #!/bin/bash
> sudo cdrecord -v -eject speed=8 dev=0,3,0 $1
> 
> 'cdrecord -scanbus' will give you the right device ID for your burner,
> and the eject is a nice touch.

Well, since we are talking about the "best" cdrecord commandline(s), and I
have some time left waiting for the bus, here is my favourite cdrecord
line:

cdrecord -v -dao -eject speed=8 dev=0,3,0 -pad padsize=64s $1

-dao burns in Disk-At-Once mode (which is essential if you burn on 
overlength media like 900MB CDRs), speed=8 sems to be the most reliable
speed for data CDs if you care more about integrity than speed, -pad
padsize=64s adds some 0 bytes as padding data, with the background that
the drives readahead won't be likely to create errors at end-of-data
when there is some empty space left.

driveropts=burnfree is an interesting option for burners that support
it; but I prefer having a coaster because of an underrun at burn time,
rather than getting read-errors later because of changing speeds and
bad pits on a "burnfree"-generated CD.

-dao will only work if the image size is known before burning, so

mkisofs lotsofoptions directory | cdrecord lotsofotheroptions -
will only work in session-at-once (default) mode with cdrecord.
Strangely, cdrdao seems to support  disk-at-once when reading from a
pipe, if you put "DATAFILE -" in the TOC file.

cdrecord SHOULD normally work as non-root, if the corresponding devices
are writable for the user invoking it, but the POSIX realtime scheduling
is only available if run as root. It should be more or less safe to
install cdrecord suid root, it has some checks built in that prohibit
reading files not owned by the user, or writing to devices that are not
burners.

Regards
-Klaus Knopper