By Timothy Prickett Morgan
Now that we all know that IBM Corp is going to bring native Linux support to its S/390 mainframes by making Linux a guest operating system under the mainframe’s venerable VM operating system (CI No 3,814), everyone is trying to figure out what the implications will be of being able to run Linux applications on mainframes. While it is a relative no-brainer to reckon that support Linux makes S/390 machines more attractive in the abstract ether where companies and government agencies put together requests for proposal, there is a real question of whether or not Linux support will have an positive effect on IBM’s S/390 software and hardware sales.
AIX support on its earlier generations of mainframes, for instance, was of little concern except at academic and government institutions who used IBM S/370 and S/390 mainframes with their adjunct vector co-processors as mini-supercomputers in the late 1980s and early 1990s. These vector mainframes took a serious bite out of Cray’s supercomputer and mini-supercomputer sales, and made life difficult for Convex and other smaller HPC vendors. It was that success that led IBM to invent the RS/6000 SP parallel supercomputers, which were announced in 1993. But no one ever really developed a commercial Unix application to run on AIX/370 under a VM partition, although there was plenty of opportunity to do so at the time. IBM’s commitment to AIX on the mainframe was always in question, especially after IBM announced a legitimate RISC-Unix offering, the RS/6000, in early 1990. AIX support never drove mainframe sales; the vector processors that used AIX did.
While Linux is one of the two fast-growing server operating systems – Windows NT being the other one, with AIX, Solaris, HP- UX, UnixWare and a few others growing more modestly or shrinking – support for Linux does not necessarily guarantee more mainframe sales. With a lot of IBM’s 20,000 or so mainframe shops sitting around with excess MIPS and the need to conduct e-business in early 2000, Linux support could just be a means of keeping those excess MIPS at work and therefore bringing in the monthly software licensing and maintenance fees.
The Apache Web server and the Sendmail email server are very popular as the foundations of an e-business platform, and supporting these two programs on S/390s within Linux partitions under VM is particularly critical for IBM even though it unquestionably wants customers to opt for the more expensive and all-IBM Lotus Domino solution on true Multiprise 3000 and 9672 mainframes. While Domino is also a great foundation for e- business, it is not the only possible foundation, and plenty of smaller S/390 customers, who have small budgets and programming staffs, will want to use Linux-based programs to save a few bucks but will nonetheless want to run those programs on S/390s because they already have processes in place to manage these machines. VM-Linux is a win-win from the point of view of the IT budget.
The other real reason that Linux on S/390s will be attractive is that MIS managers at S/390 shops, no matter how small, are empire builders and they want to be able to show their bosses in the boardroom that they have figured out a way to keep the best of the mainframe as well as extend into the open source world with Linux. There’s very little doubt that Linux on S/390, no matter how inefficient it may turn out to be, will be a lot more reliable than Linux running on a bare-bones PC box. Moreover, it will also make it possible for customers running the old VM operating system to add modern internet software without having to move up to OS/390, which is considerably more expensive and MIPS-hungry compared to VM.
Of course, the ultimate success of Linux on S/390 will depend to a large extent on the programming and technical support IBM puts behind it. If IBM is just floating VM-Linux out there so it can have a tick mark checked off on RFPs, but really has no intent on encouraging customers to use it, then maybe it shouldn’t have bothered. Ditto for charging high prices for the support. If IBM charges a high supplemental fee for VM-Linux partition support, then it defeats the purpose of giving mainframe customers a Linux option and goes against the whole open source philosophy. But if IBM provides the tools to users to help them integrate Linux workloads with their old Cobol programs and charges a reasonable price for it, then that is one less thing that mainframe shops will have to grouse about. And that is always good for the S/390 business.
