fast os switching... 1677
That's pretty good. I found Lingua::TypoGenerator that does something similar, finding fat finger typos on QWERTY keyboard. It does not do common phonetic misspellings. For example, a lot of people misspell "module" as "modual...
delfick said the following, on 06-21-06 07:36:
Another poster elsewhere in this thread has mentioned the IBM z-VM mainframe OS. If you're looking for something you can use directly, it's obviously not likely to be useful. However, if you're interested in the concepts and theory of the thing, it's worth looking at. (Incidentally, IBM has had a VM operating system since at least the late 1970s!)
z-VM and its predecessors are interesting because of the way that the hardware and software facilities are used. The IBM mainframe architecture, beginning with System-370, has virtual memory hardware. The processor can execute in either "supervisor state", in which all instructions are legal; or in "problem state", meant for applications, in which "privileged" instructions that directly touch the hardware (e.g., Start I-O, Set System Mask, Load PSW) are illegal. (This was true in System-360, too.)
VM works by creating a virtual machine that runs in problem state, although CP Control Program, the virtual machine monitor tells its operating system that it is running in supervisor state. When the virtual machine tries to execute a privileged instruction, it causes a hardware interrupt. This is handles by CP, which simulates the instruction if the virtual machine thinks it is in supervisor state. If the virtual machine thinks it is in problem state, CP reflects a privileged operation exception to it, just as the real hardware would do.
That was me, and yes, I also know about it from having been a happy user at a long-ago place of employment. Nice description, and consistent...
The VM system also uses one specific privileged instruction, DIAGnose, which is used to allow the virtual machine to communicate with CP. As its name suggests, DIAG is otherwise only intended for running diagnostics on real hardware, and can never legitimately appear in systems or applications programs.
Allow me to introduce you all to the quintessential snivelling punk troll: "Sam". (comp.mail.misc for this and a dozen or so of his other kindergarden sockpuppets) "Sam" greeted me in my first days on the...
I used VM systems quite a bit from the late 1970s through the late 1980s. They were always very reliable and robust; and, for a systems programmer, the possibility of testing new stuff during civilised hours was definitely a plus. ;-)
-- Rich Gibbs "You can observe a lot by watching." -- Yogi Berra
Linux groups from Newsgroups