Armonk, N.Y.January 25, 2002IBM today announced plans to deliver two new dedicated Linux servers, including a first-of-its-kind Linux-only mainframe that requires no traditional mainframe operating system experience.
Does this mean that Im supposed to take a half million dollar (or more) mainframe and use a free open-source operating system to control the thing? That same OS that I ran on an old 486the one that wasnt good for anything elseis going to run my enterprise computing systems? And Im going to let the 24-year-old kid with seven nose rings tailor it for our special needs? Not in this lifetime!
Thats probably a normal reaction. The words Linux and mainframe dont seem to go togetheror do they? IBM has been right a few times in the last 50 years, and maybe its jumped on the enterprise Linux bandwagon at just the right time.
So before jumping to any conclusions, take a quick look and see what this is all about.

Big Iron?
First of all, lets decide just what constitutes a mainframe.
The first computer I learned on was an IBM/360 that took up the entire basement of the chemistry building. The zSeries machine that IBM will offer with Linux is the size of a double-door refrigerator. (They are also offering a Linux package with their iSeries Applications servers.) That means we cant define a mainframe as a room-sized computer.
I have heard younger geeks refer to an AS/400 as a mainframe. That would imply that a mainframe is a system characterized by dumb terminals connected for file processing and serving. It might be better to think of a mainframe more in terms of functionality than physical characteristics.
The most important characteristic of a mainframe computer is reliabilitya system that will run for years with no downtime. It will probably have fault-tolerant devices and be upgradeable while in use. It will have the ability to handle vast quantities of data in concurrent I/O operations. It will allow for many concurrent users without becoming bogged down. It will provide for a very high level of performance, but not at the cost of reliability.
A mainframe will not be the fastest horse in the stable, but it will always finish the race. Finally, a mainframe will be expensive. All that reliability and performance arent cheap. PC or workstation machines capable of being used as servers constitute relatively small investments that can be quickly capitalized. Mainframes represent major corporate expenses that will be amortized over a number of years and which must show positive ROI.

The Mainframe Connection
The phenomenal interest in Linux among the computer cognoscenti these past 10 years has resulted in much valuable and independent research that has propelled it to the forefront in operating systems. It was only a matter of time before someone ported Linux to a mainframe.
The first such project (known as the Bigfoot i370 Project) was launched by Linas Veptas in 1998 (see www.linas.org/linux/i370-bigfoot.html). Bigfoot is a homegrown, all-volunteer effort that has been able to create a bootable Linux port for the IBM s/370. Code for Bigfoot is readily available for any willing workers to pursue this port.
Another Linux-to-mainframe port was started in 1998this one at the IBMs Bblingen, Germany, development center. It began as a secret project; Big Blue was making a ton of money selling mainframes with IBM operating systems. It was undoubtedly a bold move for the initial developers to begin work on the project. If reports are accurate, not everyone at IBM was enthralled with using Big Blue brainpower to develop an open-source operating system. Nevertheless, the project (known as the s390 project) proceeded in a semi-official skunk works way. The IBM folks didnt even work with the i370 crowd, preferring to keep all the initial development in house. In December 1999, the project was officially announced and source code released. (More information and that source code are available at www.linuxvm.org.)