Why does one use PMode???

[KieranFoot]

Hey, what is the point of pmode.
Is it to use 32bit code or is it for error checking or both? ???

[Solar]

Alas...

(Just rediscovered that word. Thanks, BI lazy! )

Trying to say it in one sentence, by enabling PMode you are enabling the MMU, i.e. virtual addressing, memory protection, paging et al.

Without PMode, you are basically running your CPU in 80286 compatibility mode.

[KieranFoot]

What are tha advantages of using pmode

[distantvoices]

oy gewalt! This one is hard. ];->

You can use (on a i386 architecture) up to 4 gb adress space for EACH Process. No process can fiddle in any other process' adress space - except of the infamous shared memory. There also exist strategies like Copy On Write - two processes share the same data pages and when one of the two starts to write - he gets his own copy - or shared code - the processes only have data pages assinged to them and share the code pages ...

I suggest you turn on your favourite search engine and STFW !

[Solar]

What are tha advantages of using pmode

If you have to ask, don't do OS development, do reading.

[Pype.Clicker]

What are tha advantages of using pmode

you're no longer limitted to DOS+WritingAssistant systems, but you can open your OS to multiprogramming, efficient GUI, third-party drivers, virtual memory, network stack, efficient disk caching and all the other things i could have ommitted.

[KieranFoot]

Sounds like a good thing to use, i'l take solar's advice and read a bit on the subject.

[Pype.Clicker]

true ... i suggest you read one chapter of a generic book about OSes (not 'Design & Implementation yet ... rather Schilberscatz&Galvin or 'Computer OS -- a modern approach') and then one of the Intel Manual ... It should give you a good feeling on what is to be done and the kind of techniques that exists to do it ...

then you'll be ready to start development: using techniques that exists to do things that need to be done

[Schol-R-LEA]

For details on working in p-mode itself, the Intel manuals are pretty much the best source; however, as a supplement to them, I found the section on protected mode operation Indispensable PC Hardware Book to be quite helpful.