CMS User's Guide (Rel 6 PLC 17 Apr81) Page 32 (32 of 493)

lIarcla 30, 1979
12.2 181 '11/370 CIS User's Guide

Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-1X8 CMS then erases all the files on that disk, if any existed, and formats
the disk for your use. When you enter the label, CMS responds by
telling you: FORMATTING DISK 'c' '10' CYLINDERS FORMATTED ON 'C(291) '. R; T=0.15/1.60 11:26:03
The FORMAT command should only be used to format CMS disks, that is,
disks you are going to use to contain CMS files. If you want to format
count-key-data disks for OS, DOS, or VSAM applications, the disks should be formatted using the IBCDASDI program.
The FORMAT command allows a choice of physical disk block size as an
option. See the for details. To
format FB-512 disks for OS, DOS, or VSAM applications, the disks can be
formatted using the INTDK stand-alone utility program. See for details. Sharing Virtual Disks: Linking Since only one user can own a virtual disk, and there are many occasions
that require users to share data or VM/370 allows you to share
virtual disks, on either a permanent or temporary basis, by "linking." Permanent links can be established for you in your VM/370 directory
entry. These disks are then a part of your virtual machine
configuration every time you log OD. You can also have another user's disk temForarily added to your
configuration by using the CP LINK command. For example, if you have a
program that uses data that resides on a disk identified in userid
DATA's configuration as a 194, and you know that the password assigned
to this disk is GO, you could issue the command:
cp link to data 194 as 198 r pass= gol DATA's 194 disk is then added to your virtual machine configuration at
virtual address 198.
The "R" in the command line indicates the access mcde; in this case
6 it tells CP that you wish only to read files from this disk. VM/370 will not allow you to write on it. If you try to issue this command
when someone is logged on to the userid DATA, you will not be able to
establish the link. If you want to link to DATA in any event, you can
reissue the LINK command using the access mode RR:
cp link data 194 198 rr gol
The keywords TO, AS, and PASS= are optional; you do not have to specify
them. You can also use the CP LINK command to link to your own disks. For
example, if you log on and discover that another user has access to one
of your disks, you may be given read-only access, even if it is a
read/write disk. You can request the other user to detach your disk INote that the password cannot be entered on the command line if the
password suppression facility was specified at sysgen. Section 1. What it Means to Have a CMS Virtual Machine 13

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Page 1GC20-1819-2_IBM_Virtual_Machine_Facility_370_CMS_Users_Guide_Rel_6_PLC_17_Apr81.pdf

Extracted Text (may have errors)

lIarcla 30, 1979
12.2 181 '11/370 CIS User's Guide

Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-1X8 CMS then erases all the files on that disk, if any existed, and formats
the disk for your use. When you enter the label, CMS responds by
telling you: FORMATTING DISK 'c' '10' CYLINDERS FORMATTED ON 'C(291) '. R; T=0.15/1.60 11:26:03
The FORMAT command should only be used to format CMS disks, that is,
disks you are going to use to contain CMS files. If you want to format
count-key-data disks for OS, DOS, or VSAM applications, the disks should be formatted using the IBCDASDI program.
The FORMAT command allows a choice of physical disk block size as an
option. See the for details. To
format FB-512 disks for OS, DOS, or VSAM applications, the disks can be
formatted using the INTDK stand-alone utility program. See for details. Sharing Virtual Disks: Linking Since only one user can own a virtual disk, and there are many occasions
that require users to share data or VM/370 allows you to share
virtual disks, on either a permanent or temporary basis, by "linking." Permanent links can be established for you in your VM/370 directory
entry. These disks are then a part of your virtual machine
configuration every time you log OD. You can also have another user's disk temForarily added to your
configuration by using the CP LINK command. For example, if you have a
program that uses data that resides on a disk identified in userid
DATA's configuration as a 194, and you know that the password assigned
to this disk is GO, you could issue the command:
cp link to data 194 as 198 r pass= gol DATA's 194 disk is then added to your virtual machine configuration at
virtual address 198.
The "R" in the command line indicates the access mcde; in this case
6 it tells CP that you wish only to read files from this disk. VM/370 will not allow you to write on it. If you try to issue this command
when someone is logged on to the userid DATA, you will not be able to
establish the link. If you want to link to DATA in any event, you can
reissue the LINK command using the access mode RR:
cp link data 194 198 rr gol
The keywords TO, AS, and PASS= are optional; you do not have to specify
them. You can also use the CP LINK command to link to your own disks. For
example, if you log on and discover that another user has access to one
of your disks, you may be given read-only access, even if it is a
read/write disk. You can request the other user to detach your disk INote that the password cannot be entered on the command line if the
password suppression facility was specified at sysgen. Section 1. What it Means to Have a CMS Virtual Machine 13

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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

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Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-118 from his virtual machine, and after he has done so, you can establish
the link:
cp link * 191 191 When you link to your own disks, you can specify the userid as * and you
do not need to specify the access mode or a password.
Iou can find more information about the CP LINK command and CP access modes in iQE Identifying Your Disk to eMS: Accessing
LINK and DEFINE are CP commands: they tell CP to add DASD devices to
your virtual machine configuration. CMS must also know about these
disks, and you must use the ACCESS command to estatlish a filemode
letter for them:
access 194 b CMS uses file mode letters to manage your files during a terminal
session. By using the ACCESS command you can control: • Whether you can write on a disk or only read from it (its read/write
status) • The library search order for programs executing in your virtual
machine • Which disks are to contain the new files that you create
If you want to know which disks you currently have access to, issue
the command: query search You might see the following display: PER191 DAT194 CMS190 CMS19E 191 A
198 B 190 S 19E I R/i R/O R/O R/O The first column indicates the label on the disk (assigned when the disk
is formatted), and the second column shows the virtual address assigned
to it.
The third column contains the file.ode letter. All letters of the
alphabet are valid filemode letters.
The fourth column indicates the read/write status of the disk. The 190 and 19E disks in this example are read-only disks that contain the CMS nucleus and disk-resident commands for the CMS system. You will
probablv use your 191 (A) disk as your primary read/write work disk.
14 IBM VM/370 eMS User's Guide

Pg. of GC20-1819-2 Rev 30, 1979 by Supp. SD23-9024-1 for 5748-XX8 RELEASING VIRTUAL DISKS When you no longer need a disk during a terminal session, or if you want
to assign a currently active filemode letter to another disk, use the eMS command RELEASE:
release c
Then, you can issue the ACCESS command to assign the filemode letter C
to another disk.
Section 1. What it to Have a CMS Virtual Machine 14.1

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