User manual

Burning disks/writing incrementally
iXOS-JUKEMAN 2.2 User Manual Pre.12/97 135
-a <size> the granularity of the control-output, which determines the
frequency with which confirmation messages are output
when recording data - default value is 1 MB, which corre-
sponds to -a 0x100000. This means that for every
megabyte of data written to the CD, a message will be out-
put. The actual value provided for <size> will be rounded
up to the nearest MB. If <size> is set to 0, then no mes-
sages are output.
Successful completion of the cdglow command is confirmed by the return
code 0: other values indicate that an error occurred. Such errors are pro-
tocolled in stderr.
When working with UNIX, the cdglow command must either be run under
root or have its s-(„sticky“-) bit set. Otherwise the speed of the data
stream is not properly maintained. The equivalent user under NT is Ad-
ministrator.
A variety of data sources can be used for cdglow, an example of which is
a file or partition with a master image formatted to ISO 9660, or another
CD drive. In the latter case, it is possible to copy the contents of one CD
onto another, providing the speed of the recorder is slower than that of the
source.
A more advanced application is, while producing the ISO 9660 file system,
to pipe this file system simultaneously to cdglow. The software is opti-
mized, so that the real-time capabilities of the operating system are fully
exploited to maintain the constant rate of data transfer. This is also the
case when the source data is dynamically generated. The precautions
mentioned above must still be observed, however.
It is important to be aware that certain drives in the IMS range simulate (“-
p”) the burn process so accurately, that successful completion of such a
simulation requires opening and closing the mail slot, or removing and re-
inserting the caddy. This is necessary to simulate the actual removal of
the CD during a genuine recording. During an actual genuine burning of a
CD, the door of the drive should of course not be opened. This is also the
case for a simulated recording process with the above family of drives and
to prevent the door being opened by mistake, the relevant functionality is
deactivated during a simulation. However, should the simulation not be
successful, it is sometimes necessary to turn the recorder drive off and on
again in order to be able to remove the disk. CD recorders in this range
include a variety of drives from Grundig, Hewlett Packard, Kodak, Mat-
sushita, Philips, Pioneer, Plasmon and Yamaha.