Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-118
The first two fields describe the device, minidisk in this example,
and the virtual address of the device. Virtual addresses (shown above
as 190, 191, and so on), are the names by which you and VM/370 identify
the disk. Each device in your virtual machine has an address which may or may not correspond to the actual location of the device on the VM/370 system.
The third field specifies the device type of your virtual disk. For
count-key-data devices, the fourth and fifth fields specify the starting
real cylinder at which your virtual disk logically begins and the number
of cylinders allocated to your virtual disk, respectively. For FB-512
devices, the fourth field specifies the starting real block numbers
where your virtual disk begins, and the fifth field is the number of
blocks allocated to your virtual disk. The sixth field is the label cf
the real disk on which the virtual disk is defined and the seventh field
is a letter specifying the read/write mode of the disk; "R" indicates
that the disk is a read-only disk, and "W" indicates that you have
read/write privileges. The MDISK control statement of the Directory Service Program is described in the DEFINING TEMPORARY VIRTUAL DISKS Using the CP DEFINE command, you can attach a temporary disk to your
virtual machine for the duration of a terminal session. The following
command allocates a 10-cylinder temporary disk from a 3330 device and
assigns it a virtual address of 291:
cp define t3330 as 291 cyl 10 When you define a minidisk, you can choose any valid address that is not
already assigned to a device in your virtual machine. Valid addresses
for minidisks range from 001 through 5FF, for a virtual machine in basic
control mode. FORMATTING VIRTUAL DISKS Before you can use any new virtual disk, you must format it. This
applies to new disks that have been assigned to you and to temporary
disks that you have allocated with the CP DEFINE command. When you
issue the FORMAT command you must use the virtual address you have
defined for the disk and assign a CMS mode letter, for example:
format 291 c CMS then promFts you with the following message: DMSFOR603R FORMAT WILL ERASE ALL FILES ON DISK 'C(291)'. DO yeU WISH TO CONTINUE? (YESINO): You respond:
yes CMS then asks you to assign a label for the disk, which may be anything
you choose. Labels can have a maximum of 6 characters. When the
message: DMSFOR605R ENTER DISK LABEL:
12 IBM VM/370 CMS User's Guide

?g. of GC20-1819-2 Rev Barch 30, 1979 by Supp. SD23-9024-1 for 5748-118 is issued, you respond by supplying a disk label. For example, if this
is a temporary disk, you aight enter:
scrtch
Section 1. What it Beans to Have a CBS Virtual Bachine 12.1