IBM's new Big Iron, code-named T-Rex, is not your father's mainframe.The zSeries 990 has brawn and - unlike its predecessors - the z990 is built to be flexible. It can accommodate varied workloads and is designed to respond automatically to shifting demands for computing power.Users and analysts say IBM's efforts to make a mainframe that's relevant for today's enterprise computing requirements are on target.Harry Roberts, CIO at Boscov's Department Stores in Reading, Pa., says his company has found the mainframe ideal for server consolidation. Boscov's halved the number of systems in its 90-system server farm by transferring applications to Linux running on the mainframe, Roberts says."The T-Rex is the next step in the evolution of the enterprise server and promises some even better performance for its Linux applications support," Roberts says. "This isn't the mainframe of our youth."IBM's mainframe has newfound relevance for two main reasons, says Gordon Haff, senior analyst and IT adviser at Illuminata. "The first is that it's continuously folded in modern technologies like Java Virtual Machines and relational databases and TCP\/IP networking," he says. "The other is that it's kept the hardware performance and capabilities competitive by leveraging development across its multiple server products."The z990 won't change the fundamental type of applications that users will be able to run on the mainframe, Haff says. But for companies that use the mainframe to combine workloads, the z990 will enable greater consolidation, he says.Seeking new workloadsLaunched earlier this month, the z990 is the result of a four-year, $1 billion investment in the zSeries platform, IBM says. It can handle nearly three times the work of its predecessor, the z900, processing up to 450 million e-business transactions per day.The heart of the z990 is a new, 16-chip multichip module (MCM) that's half the size of IBM's current chip modules and contains more than 3.2 billion transistors. Built using IBM's Silicon-on-Insulator technology, the MCM helps account for the z990's performance improvements, IBM says.Brawn aside, IBM says the real value of the z990 is that it can handle new workloads, such as managing hundreds or thousands of virtual Linux servers within one box. For that purpose, the z990 can be divided into 30 logical partitions.Linux is an increasingly important contributor to IBM's mainframe business. Shipments of Linux on the mainframe grew 45% between 2001 and 2002, and Linux systems accounted for 17% of IBM's mainframe revenue in 2002, according to Gartner.Today, more than 200 IBM mainframe customers have at least one Linux application in production on their IBM mainframes, and more than 400 additional companies are evaluating or in the process of implementing production Linux applications, the firm says.In addition to the z990's virtualization features, IBM also emphasizes the system's utility computing capabilities. Big Blue has made on-demand features a cornerstone of product development across its hardware, software and services lines.For the z990, there's On\/Off Capacity on Demand. With this feature, customers can power up additional server engines."The on-demand aspect is a step in a good direction," says Fred Betito, a director with Levi Strauss' IT Technical Architecture Group. "Being able to just - over the phone - increase your capacity is something that is of great value." Levi Strauss recently switched from Unix to an IBM z900 mainframe to run its SAP database server."The fact that you can turn on and turn off processing power and only pay for it when it is used is likely to be very interesting to large transaction clients, since many deal with seasonal demand," says Paul Mercurio, senior vice president and CIO at Mobil Travel Guide in Park Ridge, Ill.Shipping mainframe systems preloaded with extra capacity that can be turned on through software isn't a new concept - IBM was a pioneer of capacity on demand long before it occurred to anyone in the Unix camp, Haff says. "But that capacity on demand was only about growing capacity, not shrinking it," he says. "This is the first time that you've effectively been able to timeshare on your own IBM mainframe gear."Small shops welcomeOn the services front, IBM will use the z990 to sell computing power from its data centers on a utility basis to customers, letting smaller organizations take advantage of mainframe resources. IBM Global Services is deploying the z990 in its On Demand Data Centers, beginning with its new Boulder, Colo., facility.Mobil Travel Guide will be one of IBM's services customers to migrate to the Boulder facility. IBM Global Services provides the travel guide company with access to Linux-based server processing, storage and network capacity from Big Blue's e-business hosting centers.Mobil Travel Guide will benefit from an improved hardware and operating system environment, Mercurio says.At this point the additional processing power the z990 offers - such as the ability to handle 11,000 Secure Sockets Layer (SSL) transactions per second - isn't imperative for Mobil Travel Guide. "We now have more headroom than we are likely to need in our most aggressive business plans," Mercurio says. "It will be quite a while before we hit 11,000 secure SSL transactions per second."But as a former technology executive at a major airline, Mercurio appreciates what such capacity means for large companies. "In that role I grew to understand the ever-increasing demand for transactional services at large companies dealing directly with individual consumers," he says. "From that perspective the ability to handle more than 10,000 transactions per second in a single infrastructure is highly appealing to any large customer."T-Rex livesIBM\u2019s new eServer zSeries 990 mainframe breaks the 16-processor barrier and nearly triples the performance of its predecessor, the z900.\u2022Available with eight, 16, 24 or 32 processors.\u2022Runs Linux and z\/VM operating systems.\u2022Can process 11,000 SSL handshakes per second.\u2022Supports Logical Channel SubSystems.\u2022Offers On\/Off Capacity on Demand.\u2022Compared with its predecessor, it:\u00a0- Doubles the number of logical partitions to 30.\u00a0- Quadruples the number of HiperSockets for creating internal LANs to 16.\u00a0- Provides four times the memory \u2014 up to 256 gigabytes.\u00a0- Provides double the I\/O capacity \u2014 up to 96 gigabytes.IDG News Service correspondent Robert McMillan contributed to this story.