March 30, 1979
you are prompted with the message: DMSSRT604R ENTER SORT FIELDS:
and you can then specify which fields you wish the input records to be
sorted on.
Getting Acquainted with eMS If you have just logged on for the first time, and you want to try a few eMS commands, enter:
query disk a
The response should tell you that
191; it also provides information
disk and how much of it is used.
that indicates the disk may not Disks." you have an A-disk at virtual address
such as how much room there is on the Again6 if you receive an error message
be formatted, see "Formatting Virtual Your A-disk is the disk you use most often in eMS, eMS files. Files are collections of data, and may have
For this exercise, the data is meaningless. Enter:
to contain your many purposes.
edit junk file You should receive the response: NEW FILE:
EDIT:
which indicates that this file does not already exist on your A-disk.
Enter:
input You should receive the response: INPUT: and you can start to create the file, that is, write input records that
are eventually going to be written onto your A-disk. Enter 5 or 6 data
lines, such as:
hickory dickory dock
the mouse ran up the clock
the clock struck one
and down he run
dickory hickory dock NOW, enter a null line (one with no data). You should receive the
message:
EDIT:
Enter:
file You should see the message:
R; T=0.01/0.02 19:31:29 10 IBM VM/370 eMS User's Guide

Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-118 YOU have just written a CMS file onto your A-disk. If you enter:
type junk file a
you should see the following: HICKORY DICKORY DOCK THE MOUSE RAN UP THE CLOCK THE CLOCK STRUCK ONE AND DOWN HE RUN DICKORY HICKORY DOCK The CMS command, TYPE, requested a display of the disk file JUNK FILE,
on your A-disk ..
To erase the file, enter:
erase junk file NOW, if you re-enter the TYPE command, you should receive the message:
FILE NOT FOUND Most CMS commands create or reference disk files, and are as easy to
use as the commands shown above. Your CMS disks are among the most
important features in your VM/370 virtual machine. Virtual Disks and How They Are Defined Under VM/370, a real direct access storage device (DASD) unit (disk
pack) or an FB-512 device can be divided into many small areas; called
minidisks. Minidisks (also called virtual disks because they are not
equivalent to an entire real disk) are defined in the VM/370 directory,
as extents on real disks. For CMS applications, you never have to be
concerned with the extents on your minidisks; when you use CMS-formatted minidisks, they are, for practical purposes, functionally the same as
real disks. Minidisks can also be formatted for use with OS or DOS data
sets or VSAM files. You can have both permanent and temporary disks attached to your
machine during a terminal Permanent disks are defined in the VM/370 directory entry for your virtual machine. Temporary disks are
those you define for your own virtual machine using the CP DEFINE command, or those attached to your virtual machine by the system
operator. PERMANENT VIRTUAL DISKS The VM/370 directory entry for your userid defines your permanent
virtual disks. Each disk has associated with it an access mode
specifying whether you can read and write on the disk or only read from
it (its read/write status). Virtual disk entries in the VM/370 directory may look like the following: MDISK 190 2314 000 050 CMS190 R MDISK 191 3330 010 005 BDISKE W MDISK 194 3330 010 020 CMSOOl W MDISK 195 FB-512 1000 500 FBDISK W MDISK 198 3330 050 010 CMS192 W MDISK 19E 3330 010 050 CMS19E R
Section 1. What it Means to Have a CMS Virtual Machine 11