Ten years ago, many people in our industry were predicting that the mainframe would be effectively dead within a decade, killed off by the rise of distributed computing, super-powerful PCs and newer, apparently more exciting options such as the client server. Today, however, there are many indications - including some hard facts - that reports of the mainframe's death have been greatly exaggerated.

There are several reasons why this is so, and why banks, insurance companies, airlines, supermarkets and telcos - among other enterprises - have found the mainframe a hard - indeed impossible - act to follow. Reliability is of course high on the list, with many machines having a record of a decade or more of running without interruption, and with hardware upgrades taking place during normal operation. Manifestly that is a benefit that can never be overlooked in the many applications where downtime would be costly or even disastrous.

Availability is another factor, with the ‘five nines' - i.e. 99.999% availability - often being considered as the rock-bottom starting point, not the ultimate goal, in day-to-day commercial mainframe operations. On top of that, there are the unmatchable security features, the high inbuilt redundancy and disaster recovery, the extensive input-output facilities, and, last but not least, the sheer processing power and MIPS ratings that support the massive throughput often required by our larger enterprises.

All of which explains why the mainframe continues to cling onto its established ecological niches. But is there really now a prospect of more than that - of a mainframe revival, in fact, despite all the interest in distributed computing? Well, a glance at the websites of some of the main contenders, such as IBM, HP and Sun, shows that the battle for ‘big iron' is hotting up. Of course the terminology used varies, with what is in truth a mainframe (or at least a quasi-mainframe) often described as a ‘large enterprise server' or an ‘extreme-scale system' or whatnot, but the message is the same - the big beasts are fighting, and in many cases winning, a remarkable comeback. One reason is the current interest in cloud computing and virtualisation, with many people waking up to the fact that these concepts - often touted as brand-new - have been realities in the mainframe world for decades.

There is fighting talk from IBM, for example, which claims that a single System z10 mainframe is equal to nearly 1500 x86 servers, but uses up to 85 per cent less floor space and up to 85 per cent less energy - an important plus given today's energy prices. The company also highlights the increasing number of software developers homing in on its mainframe platform, with references to ‘more than 5,500 commercially available mainframe software applications from 1500 independent software vendors.' And in terms of commercial results, there are some highly respectable numbers for a platform once written off as ‘legacy'. According to IBM, worldwide System z revenue for 2008 grew 12 per cent with MIPS growth at 25 per cent; additionally, installed MIPS for Linux, Java and database specialty engines grew at 77 per cent, 61 per cent and 56 per cent respectively.

Clearly the availability of open source (often free or very low cost) systems and applications software such as Linux provided as a standard facility has given the mainframe a major boost, with such options proving popular across all sectors including public.

‘Eighteen months ago, it was not unusual to meet clients that viewed the stories of the increased exploitation of the platform as interesting, but not relevant to them', comments Mark Anzani, Vice President and Chief Technology Officer for System z.

‘Now we are seeing these clients engaging in evaluations to assess how the mainframe platform can drive down their operational costs and then moving these projects into production. Considering the typical presence in most companies of 100s of servers running various databases, such as Oracle, DB2, MySql and middle-ware, such as Websphere, Weblogic, I would encourage a CIO reading this article to consider how the centralised functionality and consolidation value of the mainframe for these workloads, can deliver reduced infrastructure cost with mainframe qualities of service to their companies.'

One recent convert to the latest IBM mainframe technology is Dundee City Council. In a case study now freely available online, the Council's IT Support Manager, Tim Simpson, says: ‘It is a very cost-effective platform for Dundee City Council. With each new generation, the mainframe becomes significantly more powerful and flexible. Aside from the extremely high reliability and security, the main advantage is its ability to run multiple systems side-by-side.'

In the financial sector, the Bank of Russia reports savings of US$400 million per annum following a move from 200 distributed servers across eleven time-zones to mainframe. Mikhail Senatorov, their Deputy Chairman, said: ‘With IBM System z, instead of buying an oversized server and growing into it over the years, we only need to pay for what we use. As volumes increase, we can ask IBM to activate more processors within the mainframe to deal with the demand.'

It is evident from even a brief trawl of the web that these stories are far from unusual. Many organisations all around the world are once again waking up to the idea that in taking the big decisions about their IT future, there is often a strong business case for the mainframe - one that the CIO would be remiss not to explore. And there is a lot to be said for a platform that enables the CIO to retake control, achieve greater visibility of costs and simplify support.

Of course, with the mainframe as with any other IT platform, peak efficiency and cost-effectiveness don't just happen by magic - they are things you need to work at. And indeed with today's budget pressures, a major focus for many CIOs with mainframe installations is figuring out how to ‘do more for less' by leveraging their existing assets (eg by modernising applications) and driving out costs. This can mean a one-off exercise, often undertaken with an expert, independent partner, or it can mean a long-term commitment to move from in-house to third-party support. And certainly many companies with strong mainframe expertise (my own included) are currently strengthening their capabilities in offerings in both these areas for their mainframe-based clients.

But regardless of whether you are in the (still formidably large) worldwide band of mainframe loyalists, or a lapsed member, I would suggest that you cannot think seriously about your longer-term IT architecture without thinking equally seriously about what today's mainframe environment has to offer.