Hardware Virtualization : A new way to Deal with Legacy Applications The time that every application in your data center was bound to a specific computer is fortunately gone. VMware virtualization technology fold many hardware systems into 'virtual machines' distributed over a few physical compute servers. The result: More efficient hardware use, less power, less floorspace, less impact of hardware failure, all contributing to significant savings. These are just some of the benefits of hardware virtualization. This approach works perfectly on applications for computer systems that are based on a modern hardware architecture. But where does that leave your business critical legacy systems, those build by the former giants of computing like the DEC VAX and Alpha, the SUN Sparc workstation or the HP3000? The applications of those systems are coded and managed differently and will not run on modern hardware. They are so different that rewriting can take years and millions of dollars in a very laborintensive process.
To the rescue comes a new technology called 'crossplatform virtualization ' . Without changing anything in the original software, it can make your legacy applications run as before on the modern virtual machines. It is a great way to postpone software migration costs, often forever. This new technology, a result of the incredible growth in compute power at an ever lower cost, can be explained as follows : Program code for a computer can produce results in two ways. It can be put on a computer and executed. Or a person could could read each program instruction and execute it one at the time, looking up its function in a computer manual. In both cases the results will be the same (although it will take the person much longer). In the second case, the program is interpreted by an 'operator'. A modern computer can be programmed with the contents of the manual of another type of computer to replace the work of the human operator, and therefore run the original program. In case of an older computer system, even if the hardware fails, we still can use its manual to write such an 'operator' program. Over the last years, technology has been developed to make the 'operator' program not only very accurate, but also very fast. This makes it possible to run unmodified applications (and their original operating system) from an older system on a modern computer, at a speed that often exceeds that of the original system. In fact Our company Stromasys SA started like many other companies in the business of providing 'traditional' software migrations. Exactly the laborintensive and very competitive business we referred to above. While we were developing tools to make the manual software conversion process easier, we came to realize that instead of adapting software to a new platform, we should adapt the underlying platform to the existing software. The pioneering work was done for the PDP11 platform, a 1970's 16bit architecture that was slow enough to be 'virtualized' with 1990's computer systems. The fact that virtualizing older computer systems is practical, we owe to Moore's law, predicting a doubling of electronic circuit performance every 18 months. This law, formulated around 1965, has held until today. Virtualization requires a lot of compute power, but for twenty year old systems this is not a problem. With Moore's law, in 20 years compute power has increased more than 1000fold, which is ample to handle the simulation of old computer circuits at high speed. And as time moved on, we successfully replaced the 1980's 32bit VAX systems and now many of the 1990's 64bit Alpha systems. We have here a new technology, serving the needs of companies that still have businesscritical older applications, at a cost that beats any traditional conversion process. The Gartner group thinks that this technology will be mainstream in 5 years. With already more than 4000 licenses sold to the 'early adopters', this is pointing to a much better understanding how we can effectively benefit from older applications that still contain much valuable business knowledge.
By : Platform Virtualization at www.stromasys.ch