From: MB [mb301@hotmail.com]
Sent: Tuesday, July 13, 2004 2:54 AM
To: Info-VAX@Mvb.Saic.Com
Subject: Re: OpenVMS probably the best designed o/s in the market...

Hack-proof and crash resistant - have you discovered the OS world's
best-kept secret?

 
 
OpenVMS offers unmatched robustness for business-critical apps 

OpenVMS (originally known as VMS) is probably the best designed and
most robust general purpose operating system in existence. It is also
one of the least-known and appreciated, simply because it works
quietly in the background without drama, unlike its noisier and more
fussy siblings and offspring.

You will typically find OpenVMS in any environment that is serious
about high availability, disaster tolerance, security, performance and
scalability, especially when running real-time applications. Users
include banks, stock exchanges, healthcare, manufacturing, aerospace,
online billing, lotteries, chip manufacturing, oil and gas production,
power stations, railways, government and secure public sector
applications. In short, anything that really has to work.

Uptime measured in years

OpenVMS system uptimes are often measured in years - it being a point
of honour to avoid rebooting and causing disruption unless utterly
essential.

There are clusters out there with uninterrupted service uptimes in
excess of 15 years, even if individual machines have been occasionally
rebooted, upgraded or replaced. That is a far cry from today's "reboot
and restart" culture, where users seem willing to tolerate disruption
to service - indeed, they have come to expect it. If only they were
aware there is a better way. OpenVMS is one of the industry's
best-kept secrets - those in the know would not consider using
anything else for business-critical systems.

OpenVMS runs on three hardware platforms: Vax (32-bit Cisc), Alpha
(64-bit Risc) and Itanium (64-bit Epic). A system disc from any Alpha
will boot and run on any other Alpha. The same goes for Vaxes,
including software-emulated Vaxes. Likewise for the latest HP
Integrity servers. OpenVMS will boot and run on anything from an
RX2600 to a Superdome. This scalability and interoperability derives
from the excellent internal architectural structure of OpenVMS.

The bigger machines (Superdome, GS1280, etc) can be hard-partitioned
to make a group of hardware resources inaccessible from other
partitions. OpenVMS also supports soft partitions, using a mechanism
known as Galaxy. This allows CPU resources to be dynamically
reallocated between soft partitions to meet changing workloads.

Partitioned systems are often used for server consolidation. Extending
that by dynamic reallocation of hardware resources leads us to
adaptive computing.

Pioneer of clustering

OpenVMS pioneered clustering in the mid-1980s and is still the
standard to which all others aspire. It provides a "shared everything"
model with minimal cluster state transition latency if a cluster
member fails.

This model allows all the resources in a cluster to be used
concurrently, not in a failover or standby mode. There are many
disaster-tolerant, split-site clusters in operation that continue to
provide uninterrupted service without loss of data, even when whole
sites fail. The largest supported OpenVMS cluster is 96 nodes - where
each node can be a large multiprocessor system.

Cluster interconnects can be anything from the original CI hardware to
Gigabit Ethernet, or even Galactic memory in a soft-partitioned
system.

Many operations staff find using better-known operating systems
frustrating in comparison to OpenVMS. The issues are primarily poor
availability and reliability, combined with the difficulty of
obtaining performance analysis and fault log data for capacity
planning and fault analysis purposes. OpenVMS is generally seen as the
gold standard for such things.

For instance, OpenVMS comes with essential tools and facilities (most
prominently, image back-up and restore) built in, rather than having
to be added on. In most cases, you simply install it, configure it for
your workload, add your applications and system-management utilities
(typically DCL command files), then run it as a black box operational
environment.

As an operating system with a real-time pre-emptive scheduling
mechanism, OpenVMS has always been capable of handling complex
real-time events. The interrupt-driven I/O subsystem design aims for
minimal latency, so OpenVMS is capable of exceedingly high, sustained
I/O throughput, especially with V7.3-2 on Alpha EV7 (Marvel) systems.
It will be interesting to see how V8.2 on Alpha and the Integrity
server range compare when it is released.

As a software development environment, OpenVMS provides a rich set of
features and programming languages, debug facilities and operating
system services.

A key aspect of the OpenVMS design is the "calling standard" that
allows code modules to be written in any language and code to call
routines written in other languages. This is a great aid to
application portability and, of course, to debugging code.

It is the architectural structures that make it easy to optimise
memory use with shared image libraries and also to deliver software
compatibility between versions of the operating system without the
need to recompile and relink applications.

Although off-the-shelf package-based products may be in fashion,
designing and implementing your own is the only way to utilise the
capabilities of the underlying platform.

This is especially true for high-availability environments where the
features have to be built into the application and need to be
reflected throughout the system architecture. Time spent
investigating, testing, customising and deploying a package can often
be better spent developing your own product layered on top of a system
designed around the minimum components that fit the overall
application architecture.

OpenVMS also has excellent security. A hacking contest was held at the
DefCon 9 conference in July 2001, where the winner was not NT, XP,
Solaris, Linux or BSD. It was VMS, which was rated "cool and
unhackable".

Not legacy nor unfashionable

OpenVMS generally appeals to those who take pride in using computer
systems to do a job effectively and reliably, rather than those who
want to live at the bleeding edge with the newest (and often immature)
technology.

Probably the biggest challenge for OpenVMS to overcome is its lack of
public visibility. This has led to the perception of it being old, or
legacy, or simply unfashionable, whereas in fact it is still under
major development. This includes secure and stable implementations of
commonly-used software such as Apache, Java, Mozilla, Perl, Python and
XML.

End-users, system managers and software developers want and need to
see sufficient advertising of OpenVMS' strengths and capabilities so
that those at board level can realise that in many cases it is a
better and more cost-effective way of delivering secure,
ultra-reliable and scalable business-critical systems than the more
fashionable and better-promoted alternatives.

Now the new HP has begun to settle down, and with the porting work to
the Integrity server range almost complete, the expectation is that we
will see the many benefits of using OpenVMS-based systems being
actively promoted. OpenVMS has a long life ahead of it, once the
current and future generations of decision-makers realise what it can
do for their businesses.

Colin Butcher is technical director of XDelta and board member of the
HP User Group