
144 Introduction to the New Mainframe: z/VSE Basics
5.4.3 What is a VTOC?
z/VSE requires a particular format for disks, which is shown in Figure 5-1.
Record 1 on the first track of the first cylinder provides the label for the disk. It
contains the six-character volume serial number (volser) and a pointer to the
volume table of contents (VTOC), which can be located anywhere on the disk.
Figure 5-1 Disk label, VTOC, and extents
The VTOC lists the files that reside on its volume, along with information about
the location and size of each file, and other file attributes. A standard z/VSE utility
program, ICKDSF, is used to create the label and VT ...