|| VMS (Unix's younger brother)
|| Unix (VMS's older brother)
- VMS was first released 1977-10-25 for the 32-bit VAX-11/780
manufactured by Digital Equipment Corporation
a.k.a. DEC (VAX-11 meant PDP-11 compatibility so VMS was probably based on RSX-11M)
- Rewritten in 1992 for the 64-bit Alpha AXP (Digital Equipment
Corporation) then renamed OpenVMS
- DEC was purchased by Compaq in 1998.
- As of 2001, Compaq still supports OpenVMS on both VAX and Alpha hardware platforms (but no new VAX hardware has been
manufactured since 2000-09-30).
- On 2001-06-25 Compaq announced they will port OpenVMS to Intel's Itanium
- Compaq merged with HP on 2002-09-03 (but will still be called HP)
- On 2003-01-31 OpenVMS engineering achieved "first boot" on Itanium (their definition of this phrase requires
a boot up, log in, execute the directory command, receiving the correct response without a crash)
- OpenVMS Releases Timeline
comment: I often wonder what this timeline would look like if corporations had been affected by
various financial crises like: the bursting of the dot-com
bubble and the Financial crisis of
- On 2015-06-31 HP announced they were outsourcing OpenVMS to VSI (VMS
Software Inc.) who committed to supporting OpenVMS on future Itaniums as well as a port to x86-64
- First written using "PDP assembler" in 1969 by AT&T's Bell
Labs for the 18-bit PDP-7 and 16-bit PDP-11/20 minicomputers (both manufactured by Digital
- Rewritten using "C" in 1972 ("C" originally was, and still is, a language built for portability. This is the main
reason why Unix is usually the first OS ported to any new computer hardware architecture)
- Only ran on DEC machines for the first 8 years of its existence (so contrary to
popular myth, the DEC community didn't hate Unix; although DEC founder Ken
Olsen did as well as VMS developer Dave Cutler)
- Ported to Interdata 8/32 and IBM 360 in 1977
- Ported to VAX in 1978 (mostly by Bill Joy)
- TCP/IP added to VAX Unix in 1980
- Since Unix was free to Universities, this OS was probably responsible for a large number of PDP + VAX sales.
- Name means Virtual Memory System
This name seems suspiciously similar to IBM's MVS (Multiple Virtual Storage) OS
- Named because it was meant to be a single (uni) user version of the
Multics operating system which was co-developed by "General Electric" and MIT
- Extensive understandable on-line help in English. Other languages include: Thai, Hanzi (Chinese), Hanyu (Chinese),
- Hebrew is supported in certain layered products like Motif and All-In-One.
Note: there may be more languages I don't know about.
- On-line help (in the form of "man" pages) are difficult to understand even if English is your first language and
you're a techie
|| much less popular than Unix because...
- ... of high license fees by DEC (many industry professionals commented that DEC's choice of '$' for the standard DCL
prompt was not an accident)
- license fees improved when Compaq purchased DEC but OpenVMS marketing by Compaq was almost non-existent.
However, Compaq did see fit to allow the start up of the OpenVMS hobbyist
group as well as loosen up the OpenVMS Educational Program
- marketing has improved since HP took over Compaq. In 2003, HP claimed the OpenVMS business was growing 10-12%
- ... initially DEC (Ken Olsen) refused to put TCP/IP on OpenVMS (this was first done by 3rd party vendors like SRI,
TGV, Wollongong, and Process Software). DEC engineers had ported TCP/IP
libraries from BSD into ULTRIX calling it UCX (Unix Communications eXtensions). After Compaq purchased DEC, UCX
morphed into a product called "TCPIP Services for OpenVMS". Process Software
now is the provider of two OpenVMS stacks, TCPware and MultiNet.
| very popular because...
- AT&T licensed it to universities for free (or almost free if you were outside the USA)
which introduced a whole generation of future IT workers to it
- Universities had access to the source code which was used to teach computer system design
to engineering students
- Universities, working with DARPA, developed TCP/IP networking for it which is the basis of today's Internet
- Universities, like Berkeley, modified it and then re-licensed it to corporations for tiny fees because schools are
for learning, not profit. Berkeley's main contributions were: "socket programming", "TCP/IP Networking", and "BSD"
(Berkeley Standard Distribution)
- In the case of free Unix today, companies make money by selling support agreements with Unix installations
- During the breakup of the Bell System
(1982-1984), AT&T tried to regain control of Unix then announced their intention to charge universities for
access to the source code. This triggered a lot of forking which (ultimately) led to the marriage of GNU (everything
rewritten except the kernel) and Linux (the kernel). The duo are now being continually improved by the brightest minds
in the world.
(invoke by entering: $edit/edt)
- EVE (Extensible VMS Editor) has no width limit
(invoke by entering: $edit/tpu)
(invoke by entering $edit/teco)
(very primitive line editor at the same level as TECO which was first used by DEC on early PDP machines)
(literally is a video screen version of 'ed')
available from x-windows, CDE, KDE (Linux), or Gnome
- nano and/or pico
- Can have multiple (up to 32k) versions of the same file name (which makes possible the easy introduction of new
program executables without a reboot)
- Directories are kept sorted (good for directory searches but adds overhead to file creation/deletion)
- Built-in RMS (Record Management System) provides native support for stream (non-record), sequential, relative and indexed files.
(Indexed files can contain up to 255 keys but you rarely encounter more than 4)
- Advanced lock queuing via the "Distributed Lock Manager" (works across clusters) ensures every process gets access
to shared resources without spin locking
- Directories easily span storage devices (or host machines with NFS)
- No built in support for relative or indexed files
- No advanced lock management (access to shared resources is usually by spin locking)
- MFS (memory file system) allows a fully functional file system to exist in memory. Very cool.
- AdvFS (advanced file system) is only currently available on Tru64 but should appear on HP-UX by 2004 (oops, this
port was cancelled)
|command interpreters/ command
- DCL (Digital Control Language) which is a command line/batch interface with a name that is suspiciously similar to
IBM's JCL (Job Control Language)
|More than 20 shells which drop into 4 flavors:
- Bourne Shell
- C Shell
- Korn Shell
- BASH (Bourne Again Shell) which is very popular on Linux systems
- DCL's philosophy assumes the user is tired, hasn't had enough coffee, and is making mistakes.
Every command is "syntax checked" and the whole line is bounced if a single error is detected. (this is humble and
much more desirable, especially in a business environment where data losses cannot be tolerated)
- command line options are prefixed with a forward slash ("/") like so
- A <space> is considered command punctuation while a <comma> is considered a list
- Suppose you want to delete all files with an extension of "junk" but you accidentally enter (notice the space
between the asterisk and the period)
$ del * .junk;*
This command will return a syntax error and immediately stop.
- Suppose you want to delete all files with an extension of "junk" or "log", and you want interactive confirmation on
every delete, and you want to log your actions
$ del/confirm/log *.junk;*,*.log;*
Note: a semi-colon is the version specifier so ";*" means all versions
- Suppose you wish to delete all multiple versions of a file with the extension of ".log" but you wish to keep the 3
most recent versions
$ purge/log/keep=3 *.log
This command will allow you to execute the same command recursively into the current directory including
$ purge/log/keep=3 [...]*.log
- Unix shells assume the user is not tired and intends everything that is typed. (this is
very dangerous but is also very fast)
- command line options are prefixed by one or two dashes.
- Two dashes ("--"): always represents a single word-based switch
- One dash ("-"): usually represents one or more single letter switches
- the "-exec" switch associated with "find" is one of many exceptions
- the "-march" switch associated with "gcc" is another
this bad command "tar -help" sends four switches to tar
is good command "tar --help" sends one switch to tar
- A <space> is considered a list separator
- Suppose you want to delete all files with an extension of "junk" but you accidentally enter the following command
(notice the space between the asterisk and the period)
# rm * .junk
This command will first delete all files then (jumping to the next item in the list) will delete all files named
".junk". If you happened to insert a "-r" switch after the "rm" command, all the directories under your current
position will be recursively deleted. If you were in the root directory, you could wipe your whole disk!
- An extensive batch processing engine is built in (supported by DCL)
- DCL scripts can be run interactively or submitted to a batch queue
- By default, batch queues are visible to everyone on the system (great for system management)
- Crude batch processing via the CRON interface
- You need access to the CRONTAB of specific users in order to view/debug queuing parameters (bad for system
- OpenVMS style batch processing support is available from 3rd party vendors (this is changing for Tru64)
- Adding spooled devices (like printers) is almost child's play
- By default, print queues are visible to everyone on the system (great for system management)
- Adding spooled devices is very difficult without GUI tools
| variables /
- Variables (DCL symbols) can be declared as global or local. Global symbols allow a process to share data with their
- "logical names" come in four flavors: process, job, group, system, cluster. A system level logical name can be used
like a system-wide variable to share information between unrelated programs and a reboot isn't required to make
changes take effect
- Exported variables allow shells to share information with their sub-shells
- To the best of my knowledge, no "logical name" concept exists anywhere in the Unix world
- System parameters are changed via the SYSGEN tool
- The system gathers running statistics and saves them in a feedback file to be used by the sys$update:AUTOGEN
| (more information coming)
| resource management
- All OpenVMS processes (system and user) are forced to engage in quota-based resource management. A process may want
to spawn forever or request use of the whole page-file but will not be allowed to do so.
- While it is true that Unix didn't have quota-based resource management for quite some time, this feature began to
appear in the mid to late 1990s
| only two levels
- limited boot (via conversational boot)
then dropping into SYSBOOT to set SYSGEN parameter STARTUP_P1 = "MIN"
then typing CONTINUE
- full boot:
the starting system executes DCL script:
| Four commonly used Unix levels: 0-6
0 = firmware
1 = single user
2 = multi-user (no networking)
3 = multi-user with networking
4 = see "man init" for info on your Unix
5 = see "man init" for info on your Unix
6 = see "man init" for info on your Unix
S = see "man init" for info on your Unix
For example, when the system is at level 1 the administrator enters "init 2" or "init 3" to open the system to other
| various startup (S) scripts in "level directories"
eg. executing "init 3" would access scripts in directory "rc3.d"
| various shutdown (K) scripts in "level directories"
eg. executing "init 0" would access scripts in directory "rc0.d" before jumping to firmware level
|| will only become more popular if...
- HP drops the price. Remember that Open Source operating systems like Linux are acquired for free. (For example,
check out products like: Gentoo, Debian, and CentOS to only name three of many)
- The marketplace realizes that the price of Alpha and Itanium hardware has already dropped significantly compared to
- OpenVMS is ported to other processor platforms like Intel's x86-64 family.
This is not as ridiculous as you would first think. Both AMD and Intel have added 64-bit extensions to IA-32 which
industry insiders refer to as x86-64 (a.k.a. AMD64, Intel 64,
bastions of hardcore OpenVMS popularity:
- Semiconductor Manufacturing
- Medical (HMOs etc.)
- Intelligence Community (NSA etc.)
- Banking Industry
- Investment, Securities, and Clearing
- Automobile/Automotive Parts Manufacturing
- Steel and Aluminum Production
- Chemical Industry
- Pulp, Paper, Packaging and Forest Products Industry
- Glass Industry
- Textile Industry
Click here for more details.
| already is popular in various flavors...
- OSF/1 was a clean version of UNIX produced (initially) by
seven companies under a collaboration known as the
Open Software Foundation. The big three included IBM, DEC and HP
- AIX (derived from OSF/1) by
- Tru64 (derived from OSF/1) by DEC. Compaq, HP
- for some reason we'll never understand, DEC kept changing the name of this product which served to confuse the
marketplace. See this list
- Starts off as Digital OSF/1 for MIPS
- Digital OSF/1 version 3.x
- Digital Unix version 4.x (a.k.a. DUNIX)
- Tru64 Unix version 5.x
- In 1998, DEC was purchased by Compaq and is now called the "Digital Equipment Corporation" division of Compaq
- In 2002, Compaq merged with HP were HP-UX was king. HP did little to market Tru64 so stopped development and
marketing of it in 2004
- HP-UX by Hewlett-Packard (HP)
- ULTRIX (by Digital Equipment
Corporation a.k.a. DEC) is officially unsupported as of 1999.12.31. This OS ran on MIPS based processors manufactured
- Linux is available free of charge under GPL (general public license) and is
distributed and supported by companies like Red Hat and SUSE
just to name two of many. See linux.org and distrowatch.com
for more info
Note: contrary to popular belief, there is no actual operating system named Linux.
Linux is really just a different Unix kernel with BSD (or GNU) applications tacked on. Read
this 'extreme tech' article for more info.
- Solaris and SunOS by Sun
- Oracle purchased Sun in 2009-2010
- BSD (Berkley Standard Distribution)
- SCO Unix by the Santa Cruz Operation
- QNX by QSSL (co-founded by Gordon Bell and
Dan Dodge of Ottawa)
- this is not the Gordon Bell of VAX/VMS fame)
- on April 2010, Blackberry maker RIM announced the purchase of the QNX product line
- BeOS by Be Inc (which they claim isn't based
on Unix but was only influenced by it. However, It supports grep, awk, Bash shell, etc. and is free)
- Mac OS X by Apple
- Easier to cluster OpenVMS machines; easier to load balance them (they've been doing it since the early 1980's using
the LAT protocol)
During a 2003-06-xx seminar I witnessed a demonstration where OpenVMS was running in a three-way cluster composed of
different hardware architectures (VAX, Alpha, Itanium)
- Multiple instances of OpenVMS operating systems can run together on the same hardware platform in something known as
a galaxy configuration. Different operating system versions are allowed which means that systems may be upgraded with
more rigorous testing.
- The POSIX interface in OpenVMS allows Unix programs to run with little, or no, modification. One popular example of
this is CSWS (a.k.a. Compaq Secure Web Server, a.k.a. Apache web server)
- Many programs written in "C" for Unix can run on OpenVMS with little more work than a simple recompile and link.
This is due to the HP OpenVMS Unix Portability
This allows valuable products from groups like www.apache.org and
www.isc.org to make their way effortlessly into the OpenVMS community.
- Most Unix clusters only use a failover strategy (so one node is usually doing nothing but waiting). However, Tru64
incorporates TruCluster technology which was derived from OpenVMS. All nodes in the cluster participate in load
sharing based upon their individual system capabilities (smaller hosts would participate less)
- Contrary to popular belief, there is no actual operating system named Unix. Unix is a
generic name which means that "Unix style operating systems" appear to have many similarities. They also have many
differences. One cool variation is GNU which is a method to get around Unix copyright problems.
- Contrary to popular belief, there is no actual operating system named Linux. Linux is
really just a different Unix kernel with BSD (or GNU) applications tacked on. Read
this 'extreme tech' article for more info.
- SCO does not own "Unix"; they only own the source code for the AT&T flavor of Unix. Click
www.opengroup.org for more details.