ICSA 202: Computing Tools

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ICSA 202 Computing Tools Environments

• Week 4 Introduction to VAX/VMS

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Multi-User Computer Systems

• Central processor/distributed terminals
• Multi-tasking allows multiple users running
  multiple processes
• Each user has individual account, can log in from
  any terminal
• Two types of terminals
• Hard-wired or dumb
• Virtual

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Centralized Data Processing

• Centralized computers, processing, data, control,
  support
• What are the advantages?
• Economies of scale (software, equipment and
  personnel)
• Lack of duplication and redundancy
• Ease in enforcing standards, security
• Simplified training and documentation

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Virtual Terminals

• Allow personal computers (Macs, PCs, etc) to
  emulate a dumb terminal in order to log into a
  central system like the VAX
• Two methods for terminal emulation
• Telnet programs for connection via the Internet
• Dial-up terminal programs for connections with a
  modem and telephone line

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Using Telnet

• PC Mac telnet programs
• Require Internet connectivity in place
• Create a terminal window for communication with
  central host
• Central host telnet programs
• Allow connections from one host-based account to
  another
• e.g. accessing your Grace account from your VAX
  account

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Key Telnet Issues

• Differences in backspace handling
• Backspace, CTRL-H, CTRL-Backspace
• Handled by some software, not all
• What you see in your telnet window is not
  actually stored on your local system
• Files cannot be locally printed or saved
• Must use FTP to retrieve the file to your local
  system

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The VAX/VMS Environment

• VAX (Virtual Address eXtension)/ VMS (Virtual
  Memory System)
• Developed in 1976 by Digital Equipment
  Corporation
• 32-bit, multitasking, multiprocessing operating
  system running on VAX and Alpha computers
• Command line interface (text only)

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Why Virtual?

• Central computer has large amounts of memory
  available
• When a user logs in, some of that memory is
  allocated to the user, creating a virtual
  computer for the duration of the login

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VAX/VMS Characteristics

• CLI (command line interface)
• Applications are text based
• exceptions are those that run under DEC Windows,
  a variant of X-Windows
• Not case-sensitive (unlike UNIX)

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VAX/VMS User IDs

• Unique identifier assigned by ISC to users of the
  VAX system
• Determines users rights and privileges,
  including access to files and directories
• Logs use of the system

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VAX/VMS Passwords

• Prevents unauthorized use of your account
• Can (and should) be changed by user as needed
  using SET PASSWORD
• Never choose a word that appears in directory
  listings for you, or can be found in a dictionary
• Use acronyms to make the password easy to remember

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Entering VAX/VMS Commands

• OS prompt is a (instead of the DOS gt)
• As a shortcut, you can type only the first four
  letters of any command
• Pressing CtrlB retrieves previously entered
  commands
• The HELP command lets you identify other commands

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VAX/VMS File Specifications
File Type
Directory Path
USER38KXAICS.FTP.SPOOLUTILITY.ZIP2
Device
File Name
Version
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Understanding the File Specification Parts

• Device Name your virtual computer address on
  the VAX
• Path directory path to the file
• File Name name given the file
• File Type type of file (word processing, script,
  etc)
• Version VAX saves a new numbered copy every time
  you modify a file

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VAX/VMS File Names

• A filename can be up to 39 characters long (no
  space is allowed)
• Typical file types
• EXE an executable program
• BAS a program written in the BASIC
• LIS, TXT a plain text file
• DIR a subdirectory

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Listing a VAX/VMS Directory

• The DIRECTORY or DIR command
• Lists current volume and directory path
• Provides a list of files or information about a
  file or group of files
• Allows use of wildcards ( or )
  

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Examining the VAX/VMS Environment with SHOW

• SHOW DEFAULT displays the default directory
• SHOW QUOTA displays the your current disk space
  quota
• SHOW PROTECTION displays the current default
  process protection

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On-Line VAX/VMS Help

• type HELP at the prompt
• Typing HELP shows you how to use help
• The second screen shows you the list of available
  help topics
• Entering a topic name provides details on that
  topic
• Pressing return at each prompt takes you back up
  and out of the system

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Creating VAX/VMS Directories

• Two equivalent commands
• CREATE/DIR .dname
• MKDIR dname
• Both create a file with .DIR extension

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VAX/VMS File Protections

• Used to keep others, or yourself, from accessing
  a file in a way you do not wish
• Four user categories
• system, owner, group, world
• Four types of protection
• R read, W write, E execute, D delete
• View protections with DIR/PROTECTION

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Why Change Protections?

• Make files available to other users
• HTML files would need to be world readable
• Data files to share with another user could be
  group readable if that person was in your group
• Prevent yourself from accidentally deleting a file

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Setting VAX/VMS Protections

• SET PROTECTION(SYSTEMprot, OWNERprot,
  GROUPprot, WORLDprot) file
• Examples
• SET PROTECTION(SYSTEMR,OWNERRWED,GROUPRW)
  payroll.lis
• SET PROTECTION(WORLDR) index.html

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Using WHOIS

• whois pxl5429 Username PXL5429
  UIC 015543,020752 Owner
  P.X. Llamas Group S422NGE Type
  Student Default Disk USER46
• whois jsk2649 Username JSK2649
  UIC 017623,026105 Owner
  J.S. Kulchinsky Group S489NCD
  Type Student Default Disk USER18

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Using Finger

• Shows users currently logged in
• If user name parameter is given, provides
  information about that user
• finger pxl5429 PXL5429 Llamas, Px
  PXL5429 not logged in Last login Fri 19-Dec-97
  256PM-GMT No plan

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Working with E-Mail

• Choose 6 from the RITMENU or type mail at the
  system prompt.
• PMDF Mail new mail system, more features
• uses EMAILgt prompt
• default system when you type mail
• VMS Mail old mail system, fewer features
• uses MAILgt prompt

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E-Mail Addresses

• Local users user ID only
• e.g. ELLICS
• Internet users full address (user_at_host)
• e.g. ell_at_it.rit.edu

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Understanding Aliases

• The e-mail equivalent of speed dial
• Different e-mail programs give them different
  names
• Address Books
• Nickname Files
• Aliases
• Nickname is private other person cant see what
  you used

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Creating Aliases

• ALIAS ADD aliasname Email-address
• e.g. ALIAS ADD LIZ ELLICSALIAS ADD LIZ2
  ELL_at_IT.RIT.EDU

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Working With Aliases

• ALIAS MODIFY alias new_address
• make changes to an existing alias
• ALIAS MODIFY/LIST alias
• modify distribution lists
• ALIAS DELETE alias
• remove an alias from the alias database
• ALIAS SHOW
• display the aliases youve created

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File Editing

• EVE editor
• invoked with EVE or EDIT
• VAX WordPerfect
• invoked from menu