z/VOS - running x86 code on z
Earlier this year, I heard of a company that tried to make a product out of dynamic binary translation of x86 code to 
z/Architecture. Recently, I decided to look at what they do.
The company is called Mantissa Corporation, and their binary translation product is called z/VOS.
Much like VMWARE, they cache the translated code, in z/VOS’s case it’s really a must otherwise I’d guess the cost of traslation would make the result unusable. I like how they used VNC (see the demo mentioned below) to give the virtual x86 box a display.
There is an official blog that has some interesting bits of information. For example, they hint at how they use multiple address spaces to give a the x86 code the illusion of virtual memory. I am not quite sure why they list Decimal Floating Point facility as a requirement. Unfortunately, it has been a few months since the last update.
Their website also happens to have a demo of a small x86 assembly operating system starting up and running under z/VOS. I find this fascinating.