=head1 NAME fms - Determine a tape's capacity and a tape device's filemark size =head1 SYNOPSIS =for html
B S<<< B<-tape> > >>> [B<-help>] B S<<< B<-t> > >>> [B<-h>] =for html
=head1 DESCRIPTION The B command determines the capacity of the tape currently in the tape device identified by the B<-tape> argument, along with the size of the filemark for the device. The filemark is also referred to as the device's end-of-file (EOF) marker, and can differ for each combination of tape and tape device. As the Tape Coordinator writes a dump, it writes a filemark between the data included from each volume and also tracks the amount of space left before the end of the tape (EOT). For some tape devices, the filemark is large enough (multiple megabytes) that failure to consider it leads the Tape Coordinator significantly to overestimate the available space. The intended use of this command is to determine tape capacity and filemark size values that can be specified in a tape device's entry in the F file. For certain types of tape drives, the Tape Coordinator operates more efficiently when the F file lists accurate values. For further discussion, see the I chapter on configuring the Backup System. Insert a tape in the drive before issuing this command. =head1 CAUTIONS Do not use this command on compressing tape devices in compression mode or with tape devices that handle tapes of multigigabyte (or multiterabyte) capacity. It does not produce accurate results in those cases. For alternate suggestions on the values to record in the B file for compressing drives, see the I chapter on configuring the Backup System. Running the command completely overwrites the tape, so use a blank one or one that can be recycled. Because it writes filemarks to the complete length of the tape, the command can take from several hours to more than a day to complete. =head1 OPTIONS =over 4 =item B<-tape> > Specifies the UNIX device name of the tape device for which to determine filemark size and the capacity of the tape it currently contains. The format varies on different system types, but usually begins with F; an example is F. =item B<-help> Prints the online help for this command. All other valid options are ignored. =back =head1 OUTPUT The command generates output both on the standard output stream and in the F file that it creates in the current working directory. The output reports the capacity of the tape in the device and the device's filemark size. The first few lines of output include status information about the execution of the command, including such information as the number of blocks and the number of file marks written to the tape by the command. The last two lines of both screen and file output provide the following information: =over 4 =item * C bytes>: specifies the size, in bytes, of the tape in the device. =item * C bytes>: specifies the device's filemark size in bytes. =back The following message indicates that the fms command interpreter cannot access the tape device. The command halts. Can't open tape drive I The following message indicates that the command interpreter cannot create the F log file. Again, the command halts. Can't open log file =head1 EXAMPLES The following command illustrates the output for the device called F: % fms /dev/rmt1h wrote block: 130408 Finished data capacity test - rewinding wrote 1109 blocks, 1109 file marks Finished file mark test Tape capacity is 2136604672 bytes File marks are 1910205 bytes The following appears in the F file: fms test started wrote 9230 blocks Finished file mark test Tape capacity is 151224320 bytes File marks are 2375680 bytes =head1 PRIVILEGE REQUIRED The issuer must be able to insert and write to files in the currently working directory, if the F file does not already exist. If it already exists, the issuer need only be able to write to it. =head1 SEE ALSO L, L =head1 COPYRIGHT IBM Corporation 2000. All Rights Reserved. This documentation is covered by the IBM Public License Version 1.0. It was converted from HTML to POD by software written by Chas Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.