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TUCoPS :: Antique Systems :: vms1.txt

Introduction to VMS part 1

Introduction to VMS - Part I

People have been asking quite a few questions about VMS/openVMS recently.  
They are finding that some machines on University subnets are using OpenVMS 
and they don't have any experience with this operating system, hopefully
this short guide will help a few people along and give them some introductory 
knowledge of VMS.

VMS/OpenVMS is a multi-tasking/processing virtual memory operating
system, VMS standing for Virtual Memory System.  It is designed to be able
to handle memory extensions beyond the capabilities of its processer (VAX - 
Virtual Address extension).  This therefore allows it to run software and
programs much larger than its physical memory and processer speed.  VMS is
also run on the ALPHA platform, which uses Advanced RISC Architecture
which provides similar power to a VAX, but the ALPHA allows more
flexibility and is slightly more technologically advanced than VAX in the
fact that it can support installation of unix based Operating Systems  as
well as VMS.  The Differences between running VMS on a VAX or an ALPHA
platform are very small as most programs can just be recompiled and run
to suit whichever architecture VMS is running on.  The float-type's and
Data Alignment technique's on VAX and ALPHA are slightly different, but
close enough to coherantly exist without causing any complimation problems
in Installation.

VMS was first developed in 1976 by DEC (Digital Equipment Corporation) as
part of their new 32 bit Virtual memory operating systems project.  It has 
since been supported by many Academic Institutions and large financial 
companies due to its large power capabilities.

It uses a command line scripting language called DCL (Digital Command 
Language) along with compiler capabilities in other more well-known
programming languages such as Pascal, Cobal, Ada, Fortran, C, Basic etc.

VMS is a very secure Operating System internally but it does often, by
default have some easy to access default logins. (similar to how IRIX
often has unpassword lp accounts etc.).

Some default logins on VMS include..


When entering a VMS system will be receive a login prompt/message similar
to this..


Username: GUEST
        Welcome to OpenVMS VAX V6.2

    Last interactive login on Monday, 14-SEP-1998 20:09
    Last non-interactive login on Tuesday, 15-SEP-1998 14:43

There are new messages in folder BLAH.


You are the presented with a prompt looking this this..



Below is a list of some basic commands that you will need to know to
navigate you way around a VMS system from the command line prompt


If in doubt, There is always the help screen.

$ help

This is large and offers detailed help on MANY commands which are not
covered here.


Logs the user out of the system.


This brings up the VMS editor (which uses a VT-220 terminal)


Accounting is the program that keeps logs of the usage users are making
from the system.


This executes a DCL eg.


This is just the same as running a unix style shell script at the command
line or even a dos .exe/.com file at dos command line.


Deletes a file on the system eg.

$ del file.dat


This will run an executable file.

$ run elite.exe


Lists the contents of a directory.

There are two widely used options that you should know here.

/brief  -       gives a brief listing of the directory, similar to ls
/full   -       gives a full listing of the directory, similar to ls -al
                but gives pages on information rather than a little
                permissions/size chart..


The show command has quite a few options and can provide a lot of
information about the system that you are on.

The command must be followed by an option, and some options include..

users   -       shows all online users at the current time.
time    -       shows the current local time of the system.
system  -       presents you with system information.
memory  -       shows you the memory the machine is using/running.
network -       displays network information to which the VMS is connected.
process -       process <processname>, similar to unix ps command.
devices -       list of devices attached to the system.
quota   -       disk quota of current user.


This command will display a file at the terminal, it is the same as the
unix cat command.

$ type <filename>


This will send mail to any machine connected to any shared network or to
another local user on the system. 


This command sets permissions of files, similar to the unix chmod command,
however it has different levels of permissions than standard unix

The most common permission for a regular users file is..

$ set file/protection=owner[rwed] leet.dat

This sets the permission of leet.dat to read (r), write (w), edit (e),
delete (d) permission of the user who owns the file. ie. owner

Other possible permissions include..

world   -       this (in place of owner) would make the file world (rwed?)
group   -       this would give permission to people in the same user
system  -       this would give permission to all users with system

eg. $ set file/protection=world[r] leet.dat

Would result in leet.dat being world readable.


Phone is a VMS chat program similar to the unix talk program.

type $ phone

and your prompt will change from a $ to a %
at this point type the username of the person you wish to chat with, you
can see if they are online via typing 'show users' beforehand.

% guest

would then start a talk session between yourself and the person logged in
as guest.


This would change the password of the user you are logged in as.

eg. $ $password fuqy0u

Would result in your new password being fuqy0u.


Create is the pascal compiler that is used to compile .pas files.

$ create whatever.pas

would then result in the production of an executable file from the .pas

Below is a list of common file extensions in a VMS enviroment, if I missed
any common ones out I apoligise..

com     -       A DCL Batch file.
cld     -       A DCL descriptor file (much like a windoze .dll). 
dat     -       A general Data File.
exe     -       An executable file.
lis     -       System Directory listing file.
dir     -       A directory/Subdirectory file
tmp     -       A temporary storage file.
txt     -       A simple text file, also used for outputted mail files.
uaf     -       A user authorisation file.
sys     -       A System Image file.
mai     -       A Mail message file.
edt     -       A command file for the VMS EDT editor.
jou     -       EDT Journal which logs any known problems.
ada     -       Ada source code.
bas     -       Basic Source code.
c       -       C source code.
cob     -       Cobol source code.
for     -       Fortran source code.
pas     -       Pascal code.
obj     -       The compiler creates object code before it links the source 

[ All examples within this text were demonstrated on an OpenVMS 6.2
system, which is a common VMS system found connected to academic networks
today. ]

9x - Spreading H/P in the new millenium.


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