PERMANENT VIRTUAL DISKS Permanent virtual disks are defined in your VM/370 directory. They can be your own personal disks which you mayor may not wish to have other
users or, they may be disks, owned by one user, but qenerally shared in read-only mode by any user on the system. Virtual
disks, definea in your directory, are made available to you when you log
on to the system. VIRTUAL DISKS If during a terminal session you require additional disk space, you can
define a temporary minidisk via the CP DEFINE command:
define t2319 as 133 cyl 15
In the previous example, a virtual 2319 disk compr1s1ng 15 cylinders is al13cated to vour virtual machine at virtual address 133. You can then
notify your operating system of the additional storage space using the
appropriate control statements or commands. the previous structure or use of this temporary disk space is
unknown, must format it to conform to the operating system you are
usinq. For :::r.JS,. use the CMS FORMAT command. For as, DOS, or VSAM applicltions, use the IBCDASDI program. When you have no further need for temporary disk space, you can
release the space to the system by issuing the command: deta:::h 133
If you 10 not release it during your terminal session, it is
automatically released to the system when you log off. NQtg: When temporary disk space is released to the system, it is not alltomat ically cleared.. Another user, requesting temporary disk space
and re:::eivinq all or part of your former disk area, can access any data
that yocr had left there. To preserve security, you should clear all temoorarv disk space before detaching it or logging off. SHARING VIRTUAL DISKS You can liso gain temporary access to someone else's permanent virtual disk during terminal session. You must know the userid of the
disk's owner, as well as its virtual address in his system. If the
owner is :::ontrolling the access to his disk, you have to obtain the read
or write password. You can then issue the command: r ,
link to smith 330 as 134 rr Irpasswdl L J
The virtual disk at address 330 in user SMITH's configuration is made
available to your virtual machine at address 134. You have read-only
access even if SMITH has the disk in write status. 16 V,/370 CP Command peference for General Users

1. For further information on virtual disks, consult 2. If is usinq the password suppression facility, specify the password on the same command line. For further information, refer to discussion of the LINK command in
section 5 of this publication. VIRTUAL UNIT RECORD DEVICES The VM/370 entries for your virtual machine usually define at
least one reader, punch, and printer. These are the virtual unit record
devices that your operating system addresses when performing unit record inpcrt and output. Rather than dedicate a real device to each virtual unit record device, VM/370 uses the concept of spooling to provide a
buffered interface between the few real unit record devices and the
relatively large number of virtual unit record devices. VIRTUAL UNIT RECORD SPOOLING Whenever your operating system creates a punch or printer file, VM/370 the output data into a spool file. VM/370 then places the
file in a queue by device type and stores it on auxiliary DASD for
eventual by the real unit record device. Similarly when card
input iata is read on a real card reader, VM/370 organizes the data into
a file and places it in the queue for the specified virtual card
reader. You can assiqn certain characteristics to spool files that
their manageability by VM/370. Some of these characteristics
spoolinq class and distribution code are assigned in the directory entries. Other characteristics such as number of
concatenation of files, destination, and hold status are set to
values whenever you log on.
enhance
such as VM/370 copies,
default
The 2P SPOOL and CHANGE commands allow you to change some or all of
the above characteristics. To chafige spool file characteristics by
device, use the SPOOL command. To chanqe characteristics by file, use
the CH!NGE command. VM/370 identifies individual spool files by assigning each file a
spool identification number (spoolid). This number ranges from 0001 through 9900 after 9900, VM/370 starts again from 0001. One series of spooliis covers the reader, printer, punch, and console spool files. VM/370 normally assigns the spoolid to a spool file when that file is
closed. !n exception to this is a console spool file where VM/370 assiqns the number when the file is opened. Also, if you close a
console file without stoppinq console spooling, VM/370 automatically
opens another console spool file with a new spoolid at the same time. Section 3. CP Command Usage 17