Despite the IT industry's efforts to improve the standard of
operating systems used in the enterprise, a significant number of
users choose to stick with apparently outmoded operating systems
for some of their most critical applications.
Legacy server operating systems from suppliers such as
Hewlett-Packard, IBM, Microsoft, Tandem and Unisys still power
important applications in banking, travel and the public
sector.
Many banks rely on core systems built in the late 1970s and
early 1980s. Every time a bank customer makes a money transfer, the
transaction passes through a legacy platform, says Julian Dobbins,
director of product management at legacy software firm Micro
Focus.
And despite the fact that these systems are frozen in time, he
sees nothing wrong with this. "One investment bank I know started
life on
Wang
then moved on to
AIX,
which it is still running. As long as these systems are still
serving the business and there are the skills available and a user
can find support, then why not?"
Outdated platforms often survive because of the risk and cost of
replacing them, according to financial services analyst TowerGroup.
Legacy replacement projects can fail, not only damaging the
credibility of the IT department but also the careers of the
managers put in charge of them.
The time and cost involved in system testing and the prospect of
a massive end-user retraining programme can prove daunting too.
Against this, a stable platform with tried-and-tested processes can
look extremely appealing.
Dharmesh Mistry was, until recently, closely involved in
technology strategy at Natwest and Lloyds TSB. "We felt that if it
was not broken, why fix it?" he says. "If you look at the lines of
code involved in migrating to something new, why bother?"
Mistry, who is now chief technology officer for software company
edge IPK, points out that money for upgrades is difficult to obtain
because budgets are divided between keeping the show on the road
and providing new functionality. Legacy systems upgrades can often
only be achieved at the expense of investment in newer systems
elsewhere.
Increasingly, users are migrating their business functionality
onto newer platforms in a mid-tier of systems, Mistry says. They
are moving away from old-fashioned green screens and turning
back-end legacy systems into file servers and archives. "First they
say let's re-face the system then they pull out the business logic
so that it is separate from the legacy systems," Mistry says.
Liverpool Victoria is one example of a company that has
successfully integrated mainframe systems with a browser-based
front end in this manner. The insurance company's car business
suffered from a website that mapped directly on to mainframe data.
By separating the mainframe processes from the front end, the
company introduced more user-friendly pages and made it easier to
add features in the future.
So it is not surprising that many users choose to modernise
their platforms rather than replace them. The dilemma is neatly
summarised in a recent survey of insurance firms by BT Global
Services. The firm's researchers reported that, Although legacy
systems were affecting the ability of insurance firms to generate
new business, only 42% said they would rather adopt new systems.
Some 37% said they planned to upgrade old systems.
Users who go for modernisation can take advantage of tools such
as XML-based web services, middleware technology and portal
frameworks that enable them to increase the life of operating
systems from the early eighties such as VMS, AS/400 and Unix.
"We can now wrap these up in a standard access layer, re-label
them as 'heritage' systems, and look forward to squeezing another
decade of service out of them," says Dale Vile of Freeform
Dynamics.
Integrating operating systems from different eras is not as
difficult as it used to be. Tools such as IBM's WebSphereMQ message
broker can cater for as many as 50 operating systems, providing a
convenient way of passing messages between applications running
under incompatible operating systems.
However, integration still poses a number of challenges. Modern
computing is based on the concept of sessions, conversations that
may involve several different systems. This approach to computing
was unheard of when IBM 360 ruled the roost and communications took
place on a much more limited scale.
Not only does the difference in transaction styles throw up
compatibility issues, but communications involving legacy systems
can consume more network bandwidth than their modern counterparts,
owing to the serial nature of their output.
There are problems too with security. At the most basic level,
mainframe password protocols can make it difficult to change
passwords or to have more than one password. More seriously,
maintaining security on legacy systems can be difficult, since
users cannot expect automatic protection from new threats.
"Users of legacy operating systems do have to confront the fact
that they will not have security patches delivered to them," says
Vijay Samtani, manager in Deloitte's security and privacy services.
"So, to go alongside their patching strategy, they need to develop
a strategy to manage the risks of having unpatched software in
their enterprise."
They will have to weigh the benefits of keeping a legacy
operating system against security worries and the cost of
protecting it by means other than patching. "Supporting a legacy
operating system in your enterprise is as much about risk
management as it is about traditional IT service management," says
Samtani.
Sometimes the very age of a system can increase its security.
For example, it is unlikely that an ATM system running on Windows
NT4 over an IBM SNA network will be troubled by viruses or
hacking.
Increased regulation in many industries and an emphasis on
corporate governance also makes an impact on data storage. Many
authorities insist data be kept in a certain way or that it be
available for inspection within a given timescale.
"There are challenging issues around the way data is stored in a
legacy system," says Tom Saunders, who has run many IT departments
as an interim manager. "When you want to bring it back recovery can
be a nightmare. Most organisations opt to extract data into flat
files before it is stored."
The cost of running elderly software is often inflated by the
outdated hardware it is mounted on. However, virtualisation has
helped cut the umbilical chord between legacy systems software and
the hardware it was originally designed to run on, allowing users
to replace their hardware and consolidate legacy systems on a
single server.
However, although shrouding older applications in
web-services-based interfaces helps systems integration and the
user experience, it does not particularly help with the growing
challenge of maintaining legacy skills or the availability of
ongoing support from suppliers, says Vile.
Skills are a hot potato. "There is definitely a skills
shortage," says Alan Rodger, senior research analyst at Butler
Group. "It is a ticking clock because you cannot expect to be able
to find people with specific legacy skills for ever. Legacy skills
are not attractive ones to have."
Rodger gives the example of a contractor who specialises in the
Pick operating system, a 1970s system developed during the Vietnam
War. The contractor has several clients who are completely
dependent on him, which means he must be contactable at all times.
He earns enough money to work a three-day week, but will not be
around forever.
Although few IT shops will find themselves relying on
individuals like the Pick specialist, there are plenty of personnel
problems associated with legacy systems. Users can end up dependent
on a small number of older staff to maintain their systems, people
who inevitably move on or retire, taking their knowledge with them.
Service companies may be able to fill the gap, but ultimately they
too are struggling to find experts with the right skills.
Supplier strategies play a key role in creating legacy systems
and determining their longevity. Users determined to avoid upgrades
can end up in tussles over support with IT companies. Microsoft
takes one of the hardest lines in the industry, branding all
versions of its operating systems except the current one as legacy.
The stance has sparked user rebellions in the past.
But even companies more at home in the datacentre are keen to
edge users on to an upgrade path. Negotiations over support for
legacy systems can be tough, with suppliers demanding extra
payments for maintenance and trying to impose cut-off dates while
customers hold back for a better deal.
Mainframer Unisys is sensitive about the whole idea of legacy
operating systems. "People have tried to associate legacy with IBM
z Series and ClearPath," says Bob Tillotson, vice-president and
general manager of Global ClearPath sales at Unisys. "But the term
legacy is inappropriate as we are delivering appropriate systems.
It is a pejorative word to position something as old."
Tillotson points out that operating systems are living longer
than they did in the 1970s, and only a handful have terminated, as
he puts it, since then. Unisys has extended the length of support
for its operating system releases and put new policies in place so
customers do not have to keep moving from one version to another,
he says. The company is not alone in keeping its legacy systems
alive. The IBM mainframe has evolved to the modern zSeries and the
AS/400 to the equally up to date iSeries.
It is difficult to generalise about legacy operating systems.
Not only are there many reasons for sticking with them but many
different ways of managing them. One constant theme is that no
legacy operating system can go on forever.
One day the cost and inconvenience of maintaining a legacy
system will tip the balance in favour of an upgrade. The trick is
to know when that time has arrived.