[Sussex] AppleScript and Red Hat 8.0

[Tony Dart]

Hi

Geoff wrote
>
> I sense that Tony feels he has a closing argument here... if so he has
> underestimated my bloody mindedness on an epic scale ;)

and once more I am forced to agree with him entirely! ;-}
>
> <sidetrack reason="technical point">
> I would debate the idea that this is any different for Apple machines than
> it is for PC's.  Message queues are common to most modern operating
systems.
> There are still hardware interrupts involved in all cases - the hardware
> interrupt triggers the software action that inserts messages into the
queue,
> if there were no hardware interrupts then nothing would ever happen.
>

If a hardware trigger signal causes the premature stacking of another
process, service of the trigger, then back to the main process then I would
call this an interrupt. But if the signal is, say, buffered and the main
process is terminated at a pre-determined time to poll the buffer then this
is pre-emptive scheduling, not an interrupt - the basis of most large
time-sharing systems. And if the hardware trigger signal causes a software
event to be placed in a queue for processing after the natural termination
of a certain part of the main process (such as 1 iteration through the major
program loop) then this is event processing (a la Mac) and is not an
interrupt - although in all 3 cases the effect is (almost) the same - the
difference being latency.

>
> If as you say, the level of scripting control provided by AppleScript is
> such that it controls applications by reading from, and writing to their
> message queues then I have a point to make:

No - applications do not maintain separate message queues - they write to
the system queue and although they can read from it they would not normally
do so. An app opens a document by sending an 'open document event' to the
main system queue - AppleScript would activate the app and then send the
same event to the queue - it is driving the system, not the app interface.

> Red Hat 8.0 and SuSE 8.1 both work straight out of the box for 99.9% of
PC's
> and both could be installed by a trained chimp.

Ook! Convinced - will install RH8 tomorrow. Now in process of backing up Mac
to install OS X. If all OK then will have a spare PC (ex-Win Me) to play
with at home ...

Tony