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S/390: The Linux Dream Machine - page 3

Linux Everywhere: More than a Slogan

  • February 23, 2000
  • By Scott Courtney

If you've read all that came before, you have probably decided by now that I am some kind of mainframe bigot, that I'm one of those people who likes to sit in a glass room with a raised tile floor and sneer at the little toy PCs. Actually, quite the opposite is true. I am a PC maven through and through. I got started in computers by designing my own 8080A system and I will never willingly give up the responsiveness, flexibility and control that I have with a standalone CPU.

Besides, for all their awesome power and scalability, the truth is that I don't like the command shells that are standard on either VM or OS/390. VM has a thing called Conversational Monitor System, or CMS, and OS/390 offers Time Sharing Option, or TSO. I've used both for years, and they are immensely capable environments. I can't knock either of these for power or quality, but their command syntax just doesn't feel as elegant to me as does the UNIX/Linux shell. Call it personal preference, but I really love things like command substitution and environment variables, and the fact that the shell is itself a programming language so I can do for and while loops interactively. CMS and TSO can run REXX programs or scripts, but with bash or ksh you live inside a script all the time. VM has a thing called "CMS Pipelines," and it's truly awesome in what it can do. VM/Pipes is sort of like all of the standard UNIX text commands (head, tail, cut, grep, tr, and so on) rolled into one. But in my opinion it's not quite as seamless as the simple use of the vertical bar in Linux to imply I/O redirection. And I have never cared for the 3270 terminal's insistence on processing data screen-by-screen rather than character-by-character. I know why they do it--better system performance for data entry--but that doesn't mean I have to like it.

Driving bash feels like being in a snappy European sports car, while CMS feels like being in a solid, luxurious Lincoln Town Car. I just happen to like the sports-car feel better; as I said, it's just personal preference. But ever since I began to hang around with my company's mainframe gurus, and truly begin to understand just what a powerhouse that big iron really is, I've secretly longed for the day when I could have the best of both. I want nothing less than the sheer might of a mainframe combined with the nimbleness of the Linux shell. I thought it was in my grasp when IBM released the UNIX System Services feature on VM Open Edition, which includes a POSIX-compliant environment that runs inside VM. It was pretty good, but it didn't quite measure up to my expectations for a variety of reasons.

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