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"David H. Burns" <dhb### [at] cherokeetel net> wrote:
> A peek function would still be useful, but a poke function on a multi
> tasking system where
> the operating system is in RAM ... well at best, you might reboot a lot.
Would be very boring these days: At worst, poking around would get that
particular app jam itself, and you'd have to kill it via the task manager.
The operating system (with lots of hardware support from the CPU) does a good
job at not allowing any app to peek or poke around in memory allocated to other
programs or the OS. Applications even typically get to see different sections of
physical memory at any particular address.
BTW, in C you can actually peek & poke around as you like on virtually all
platforms, simply by assigning an arbitrary integer value to a pointer and then
accessing the memory location pointed to.
May result in the application getting terminated for an access violation though,
courtesy of Intel's "protected mode" and paging mechanisms, which can be used to
automatically trigger a hardware interrupt when certain memory address ranges
are accessed, so that the OS can take over and handle the access accordingly
(killing a misbehaving program, swapping virtual memory back in, or the like).
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