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Read and write-once support for CD-R and CD-RW drives is introduced in OpenVMS Alpha Version 7.3-1 on the AlphaServer DS25 system. OpenVMS supports only qualified CD-R and CD-RW drives. For more information on Alpha systems and the drives they support, refer to the appropriate page at the following Web site:
http://h18002.www1.hp.com/hps/buy.html#configure
The write process creates a CD-ROM in Files-11 format. Any
supported CD-ROM reader on a computer running OpenVMS will be able
to read the CD-ROMs you create. The write process does not create
a CD-ROM in ISO 9660 format. For more information, refer to the
Guide to OpenVMS File Applications.You can create a CD-ROM that contains data files, but audio recording is not supported at this time. Writing to CD-RW disks, which are rewritable, is also not supported at this time. |
The first step is to create a logical disk and container file on your hard drive. Organize the directory structure, volume information, and files on the logical disk as you want them to appear on the CD-ROM.
The second step is to run CDRECORD.COM to transfer the contents of the container file to a blank CD-R disk. CDRECORD.COM provides a set of commands you can use to:
To view online help about CDRECORD.COM, enter the HELP command at the DCL prompt ($), as follows:
$
@SYS$MANAGER:CDRECORD H
Preparation
When you are ready to create a CD-ROM, make sure you have:
To verify that you have the device name for the drive, enter the INQUIRE command followed by the device name. For example:
$
@SYS$MANAGER:CDRECORD INQUIRE DQA1:
The system verifies that DQA1 (or whatever device name you
entered) is a CD-R or CD-RW drive. It also displays the read and
write speed of the drive.
Setting Up a Logical Disk and Container File
You set up the structure and data you want on the hard drive,
then use CDRECORD.COM to transfer everything to a blank CD-R disk.
You do this by first creating a logical disk on the hard drive that
you can mount, dismount, and generally treat as an actual disk.
You also create a container file because CDRECORD.COM needs to work
with the files on the logical disk as a single entity.
For best performance, clean up and defragment the hard drive on which you will create the logical disk and container file. For more information, see BACKUP/IMAGE in the HP OpenVMS System Management Utilities Reference Manual: A--L.
Use the SETUP command in the following format to create a logical disk and a container file:
@SYS$MANAGER:CDRECORD SETUP filename LDAn: label nnnn
where:filename is the name of the container file. Follow the usual rules for naming files and include a file extension.
LDAn: is the name of the logical disk and can have a value of LDA1 to LDA9999.
label is the volume label you want to give the logical disk and the CD-ROM you will write. Follow the usual rules for assigning volume labels.
nnnn is the number of 512-byte blocks you want to allocate for the container file. The number must be a multiple of 4. The default value is 1250000 (640 MB).
The container file must not be larger than the available space on the CD-R disk you are going to write to. Also, check the available space on your hard drive to make sure you have enough room for the container file.
In the following example:
$ @SYS$MANAGER:CDRECORD SETUP TESTFILE.DSK LDA1: FRED 1250000TESTFILE.DSK is the container file name and extension.
LDA1: is the device name of the logical disk.
FRED is the volume label of the logical disk and the CD-ROM you will write.
1250000 is the space (in 512-byte units) that will be allocated on the hard drive for the container file.
Once you have created a logical disk and container file on your hard drive, you can populate the logical disk with directories and files.
Populating the Logical Disk
Mount the logical disk and use OpenVMS commands such as CREATE/DIR,
COPY, etc., or Record Management Services (RMS), to create files
on the logical disk. You can dismount and remount the logical disk
any number of times and update its contents as often as necessary.
You can also apply UIC-based security and access control lists (ACLs)
to files.
Once you are satisfied with the contents of the logical disk, you are ready to write it to a CD-R disk.
Writing to a CD-R Disk
When you are ready to write to a CD-R disk, do the following:
@SYS$MANAGER:CDRECORD WRITE
filename LDAn: DAQnn: laser speed priority
where:A CD-R or CD-RW drive might write at one of a number of fixed speeds (for example, at 2x, 4x, 8x, 16x, and 20x). Enter an override speed to set the drive to one of the speeds that it is capable of using. If you enter an unsupported speed for the drive, CDRECORD.COM picks a supported speed close to what you specified. |
You should know whether or not your drive is required to record at a specific speed. With some drives, to minimize errors, you might need to record at a slower speed, depending on the ability of your computer to keep up the pace. You do not want the write operation to pause because the computer cannot provide the data quickly enough. Some drives can accommodate sporadic recording activity ("burn-proof" drives). Raising the priority parameter can also alleviate problems.
In the following example:
$ @SYS$MANAGER:CDRECORD WRITE TESTFILE.DSK LDA1: DQA0: 0 12TESTFILE.DSK is the container filename and extension.
LDA1: is the device name of the logical disk.
DQA0: is the device name of the CD-R drive.
0 enables the laser beam.
12 is the recording speed.
Verifying
a Write Operation
After you create CD media, you can verify that the data written
to a CD-ROM can be read back and that it matches the original data.
To verify data, enter the VERIFY command, using following format:
@SYS$MANAGER:CDRECORD VERIFY filename LDA1: label DQA0:
where:filename is the name of the container file and its extension.
LDA1: is the device name of the logical disk.
label is the volume label of the logical disk (and the CD-R media).
DQA0: is the OpenVMS CD device name.
Reusing a Container File
When you have finished writing the contents of a logical disk
to one or more CD-ROMs, you can delete the container file or reuse
it, if you plan to create more CD-ROMs in the future. The advantages
of reusing it are:
Reusing a container file DELETES the current contents of the file. |
@SYS$MANAGER:CDRECORD REUSE filename LDAn: label
where:filename is the name of the container file and its extension.
LDAn: is the device name of the logical disk.
label is the volume label of the logical disk.
In the following example:
$ @SYS$MANAGER:CDRECORD REUSE TESTFILE.DSK LDA1: FRED
TESTFILE.DSK is the name of the container file.LDA1: is the device name of the logical disk.
FRED is the volume label of the logical disk.
Use OpenVMS commands to create directories and files. Once you are satisfied with the contents, you are ready to write to a CD-R disk with the CDRECORD WRITE command.
CDRECORD Command Summary
The format for the CDRECORD.COM command line is:
@SYS$MANAGER:CDRECORD command [parameter1|parameter2|...]
The CDRECORD commands are:CDRECORD.COM Commands and Parameters summarizes the parameters for each command.
The steps for creating a CD-ROM are:
$ @SYS$MANAGER:CDRECORD INQUIRE DQA0:
$ @SYS$MANAGER:CDRECORD SETUP TESTFILE.DSK LDA1: FRED 1250000
$ @SYS$MANAGER:CDRECORD WRITE TESTFILE.DSK LDA1: DQA0:
1 The CDRECORD software internals were developed outside of HP, and are protected by the GNU General Public License Version 2. Copies of the sources and the GNU license are on the Open Source Tools CD, which ships with each version of OpenVMS and is also on the OpenVMS web site.
( Number takes you back )
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