Re: How to implement lexical closures?

glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:
>The IBM PL/I compilers that are not subset have tasks, not threads.
>
>OS/360 MVT (Multitasking with a Variable number of Tasks)
>has the appropriate support for subtasking. Since OS/360 runs
>everything in one address space, it isn't so easy to say
>what the difference is between threads and tasks.


My impression is that "task" is a less refined concept. When you have
an OS that supports running multiple things at the same time, it's
called multi-tasking. When the OS has separate address spaces, and
each task has an address space, the tasks are called processes. If,
in a system with separate address spaces, you have several tasks
sharing an address space, they are called threads. Also, I have used
"task" when talking about a system that has an n:m relationship
between tasks (as visible to the programmer) and threads (as visible
to the OS, aka kernel threads).


- anton
--
M. Anton Ertl
anton@mips.complang.tuwien.ac.at
http://www.complang.tuwien.ac.at/anton/
[Remember that this is 1964 terminology. You'll find that an OS/360 task
is what we now call a thread. But this has gone pretty far from
compilers. so I'll call a halt here. -John]

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