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.)

Virtually Speaking
Back to the press release. IBM is offering its zSeries mainframes with Linux as the OS. These servers are built around multiple (up to four) 64 bit z800-0LF processors. The boxes come with all four processors installed but you only pay for the ones actually turned on.
These are powerful systems with built-in fault avoidance and error recovery. They support gigabit Ethernet and high speed Token-Ring networks. Linux could be loaded directly on native hardware in a logical partition (LPAR) and you would have one heck of a server. But that doesnt even come close to justifying Linux on these things. What makes it all worthwhile is VM (Virtual Machine). VM was developed at IBM in the 1960s to allow multiple versions of an operating system to run on the same machine.
Each virtual machine is, for all practical purposes, a standalone zSeries mainframe with its own virtual memory, virtual devices and virtual processors. You could bring one virtual machine to its knees and it would not effect the operations of any of the other virtual machines. Youre not limited to running Linux under zVMany operating system that natively supports the box will run. That provides the ability to run traditional mainframe applications under OS/390 on the same box as your Linux VMs.
This Is the Cool Part
This is all pretty exciting stuff if youre a computer guy (or gal)kick-butt servers, open source code, skunk works, etc. Cool stuff isnt cool, though, unless it improves the bottom lineand that is just what this new IBM initiative may do.
You can buy a single processor zSeries Linux machine for around $400,000. On that single piece of hardware you can run 20 or more functionally independent Linux virtual servers.
Think about the number of PC or workstation-type servers youre currently running. Were talking file servers, print servers, mail servers, Web servers, and database servers. How much money would you save if you could get rid of all of those servers and wrap them up on a single platform? (Dont forget that all these servers will be able to communicate at memory speed). How many admin people will you still need? How many hardware guys wont have to keep them all running?
With a single mainframe, it may be possible to replace all your current Web servers. Youll be able to create internal and external firewalls containing your DMZ on the same piece of hardware. You can build a Web farm with truly identical server configurations. Youll be able to maintain replication and fail-over servers for almost nothing. One or more servers can be brought down without affecting the rest. Even if a hacker achieved root on one Linux server, the security of the remaining servers will not be compromised.

Beyond Big Blue
The possibilities here are fascinating. This is a truly innovative and worthwhile way to justify the cost of very expensive pieces of hardware. IBM is not going this alone. Big Blue grabbed a lot of publicity with its press release (it was timed for last months Linux World). Compaq is offering Linux on its ProLiant servers. Hewlett-Packard announced two new servers that will support various Linux versions. A Linux version of Suns iPlanet Application Server is in the works.
Theres no longer any doubt thatno matter what your businessLinux is here to stay.

Special Reports /

The Iron Penguin

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