Re: Supervisor mode & multitasking

["Petr Stehlik" <pstehlik@zln.cz>]

>> The problem is that a generally available system call for switching
system
>> to single mode might be (and sure will) misused very often (for example
>> Thing - widely spread program, probably most used desktop - and it will
turn
>> MiNT into singleTOS?).
>
>Yes, it may be. But sometimes it may be nice to have an option to
>write/run a program, which takes an advantage of being the only task in
>the system to utilize the full processing power of the CPU. As the

I don't agree. We should improve MiNT scheduling so a time intensive task
will  get 97% (or more) of CPU power. Then, you wouldn't need to switch to
singlemode.

>accounts etc). At the other hand, there's some old, but still decent
>software, that can't run in multitasking and it is a pain to reboot each
>time to TOS and back. A good example is Pure Debugger (MONST also doesn't

go for 68040 - PureDebugger doesn't work there, so you have one problem less
:-)

>work very well under MiNT). If you use a debugger to trace own program,
>such a session takes rather minutes than hours, then you'd need to reboot
>back to MiNT for other minutes (to fix something and compile program
>again), then back to TOS to run the debugger to see if everything is OK...
>pain, pain, just pain.

So we actually need a new debugger for MiNTOS, not singlemode in MiNT. OK, I
agree - so let's develop a new, MiNT friendly debugger. Sven started work on
something, it could even utilize special MiNT debugging features.

>> And then, suddenly someone writes an "interface" for running all sorts of
>> programs in singletasking under MiNT. At the end you will not be able to
>> e.g. compile, render or listen to music in background, because nearly
every
>> program in foreground (including your favourite desktop) will stop the
task
>> switching.
>
>Well, horrible scenario. :) But notice now any program can stop
>multitasking as well, using Supexec() for example (as EmuXL does when
>entering the 6502 emulator). And, besides, Thing desktop doesn't need this
>for itself, but for possibility of starting old software (like Pure
>Debugger) in single mode when necessary...

sorry, I am still not convinced the single mode is really neccessary. It
might be handy, but the danger of misuse is rather high, I am afraid.

Similarly, the system call for switching to super mode while allowing task
switching - this might affect complete system stability. Again, with such
call there might appear applications which will be dangerous for whole
operating system. Do I see the future too black?

Petr