Ibm System Three Ninety

System 390, S/390.

The high-end MainframeComputer from InternationalBusinessMachines (IBM). This is the oldest computer still being manufactured (the S/390 was created in the 60s). In recent years, IBM has been having record-breaking sales levels of these machines. CharlesSchwab? recently upgraded from two of them to three of them for their web site. And IBM recently ported linux. Linux can run on the raw metal, or on the VM system. A low-end model with linux on raw metal is $125k, and $20k more with VM. I think that is for 8 300MHz Power4 (or was it Power5) chips, which are like a 300MHz PPC, except far faster. So, it might compare favorably to 8 gigahertz intel chips, but that would be a rather poor comparison to set up in many ways.

The really cool thing about this is that an ISP could buy a single one of these instead of 40 intel based linux machines. The S/390 should be more stable, and in addition, if any particular linux partition got cracked, crashed, or corrupted, it could be reinitialized from a disk image in a matter of minutes. That means that virtual hosting could actually offer a full virtual machine with full control to the customers.

But... Why?

Why anyone would want Linux running on a S/390's bare metal is beyond me. It seems like it would be a waste of hardware. First, Linux doesn't scale that well beyond 2 CPUs, and second, plain linux can't really take advantage of the hardware's other features.

Methinks you are working from old assumptions. In fact, Linux scales quite well on the S/390. And, of course, it's not "plain linux" but a "Linux-based OS that runs Linux apps" that IBM has developed, so of course it takes advantage of all of the special S/390 hardware.

See LinuxCpuScalability

These days, a lot of similar things are done in other partitionable systems and quite especially XenHypervisor. Mostly running Linux, of course.

I don't think you are getting your facts quite right. According to my research:

S/360 was designed in the 60s. The S/370 came afterwards; it was backward compatible, but it was most definitely not a S/360. The S/390 came out in the 90s/2000s or so, and is consequently not an S/370. By your logic, a Pentium Xeon quad-core is still an Intel 8088. This is most definitely not the case, despite the backward compatibility that is retained.
The S/390 uses a S/390 microprocessor. It is not a Power-based architecture. You must be confusing the S/390 with the AS/400 series, which do utilize a modified Power-architecture processor, tailored specifically to make executing the AS/400's virtual instruction set easier/faster.

--SamuelFalvo?