Sun: Linux on the Mainframe–Not a Good Idea

“Just as it is important to understand when technology
can provide you with an advantage, it is equally valuable to know
when a technology is not suited to a particular task regardless of
how ‘hot’ that technology might be. Sun does see a place for Linux
in the IT infrastructure, as evidenced by our recent announcement
to ship Linux-based servers. Sun introduced low-priced, horizontal
Linux servers as an alternative to proprietary systems. Suited for
Web delivery at the edge of the network, Linux servers offer an
alternative to proprietary and closed environments such as
Microsoft Windows.

Recently, IBM announced a new ‘Linux-only’ mainframe, the z800,
which IBM is promoting as a way to consolidate multiple Linux and
Unix[r] servers(1). Running Linux on a mainframe doesn’t change the
fact that you must still maintain an expensive, proprietary system,
defeating the whole purpose of introducing open standards like
Linux. Although it’s technically possible to configure such a
system, the question remains, ‘How well-suited is the system to the
task?’

Linux on the mainframe just doesn’t compute. Here’s why:

Linux on the mainframe is actually hosted by another proprietary
operating system, z/VM. The optimized operating system for IBM
mainframes is z/OS, formerly called MVS(2). Compared to z/OS, z/VM
is a niche operating system with virtual machine (VM) support for
new hardware features added late or often not at all(3). And Linux
isn’t designed to run in a virtual machine; implementation
decisions that make sense on PC hardware don’t fit well in a
virtual machine(4). This is Linux. It’s designed for Intel. It’s
not tuned for the mainframe hardware in which it’s running.”

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