Configuring mksysb image on system backup tapes

Use the mksysb command to ensure that the boot image, BOS Installation/Maintenance image, and the table of contents image are created with a tape block_size value of 512.

The boot image, BOS Installation/Maintenance image, and the table of contents image must be created with a tape block_size value of 512. The mksysb command ensures that the block size is 512 when these images are created. There are no restrictions on the block size used for the fourth (system backup image) on the tape. The block size of the system, before it was temporarily set to 512, is used for the fourth image on the tape.

The value of the block size must be saved in the /tapeblksz file in the second image on the tape. The second and fourth images are stored in backup/restore format. Again, mksysb ensures the correctness of the tapes created by using the mksysb command.

If there are problems with the bosinst.data file, the image.data file, or the tapeblksz file, these files can be restored from the second image on the tape and checked. These files, as well as commands necessary for execution in the RAM file system (when running in maintenance mode after booting from the tape), are stored in the second image.