[sedachv]

Pretty much everything in your post is wrong. IBM mainframes are heavily virtualized and have very good support for moving to larger address spaces. VM and MVS moved from 24-bit to 31-bit to 64-bit address spaces. You can run the old 24-bit applications and upgrade them as needed. Even assembly programs - the old assemblers and instructions are supported on newer hardware. System i (System/38-AS/400) was built around a 128-bit virtual address space from the start. There is much more support for fixing old software on mainframes than there is for proprietary 1980s-era PC and Unix applications.

I have no idea why you think running 32-bit today is "odd." 32-bit desktops and small servers are still perfectly usable today. 32-bit microcontrollers are going to be around for a very long time (just look at how prevalent the 8051 remains), and a lot of them are going to be running Linux. It also makes a lot of sense to run 32-bit x86 guests on AMD64 hypervisors - your pointers are half the size so you can get a lot more use out of 4GiB of memory.

[ajdlinux]

Also note that IBM mainframes can run 64-bit Linux just fine. Indeed, IBM's been marketing its LinuxONE mainframe line as a z series machine that doesn't run z/OS at all.

(disclaimer: IBMer, but not a mainframe person)

[drzaiusapelord]

We're talking Mainframe system designs and code from the 70s and 80s. No they aren't running 64-bit linux. I think you guys need to re-read my post. The legacy systems on Y2K had none of these features.