Hardware multitasking

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BOTOKILLER

Joined: 07 Jan 2011
Posts: 154
Location: Ukraine

BOTOKILLER 14 Apr 2011, 05:09

Hi everyone!
I saw that stuf on wikipedia and I have some questions
1. Is it worth of using it?
2. How to code that stuf?

14 Apr 2011, 05:09

Tyler

Joined: 19 Nov 2009
Posts: 1216
Location: NC, USA

Tyler 14 Apr 2011, 06:05

I've read it's not the most efficient way to implement multitasking. To code it, you open get a copy of Intel Manual 3A, build a GDT with a TSS descriptor in it, and a TSS.

Also, you need to make friends with chap 7 of the same manual.

14 Apr 2011, 06:05

BOTOKILLER

Joined: 07 Jan 2011
Posts: 154
Location: Ukraine

BOTOKILLER 14 Apr 2011, 09:38

what are the cons and pros of it?

14 Apr 2011, 09:38

ManOfSteel

Joined: 02 Feb 2005
Posts: 1154

ManOfSteel 14 Apr 2011, 10:13

BOTOKILLER wrote:

Is it worth of using it?

Not really. It's a bit slower than s/w multitasking, has a lot more overhead and provides no real advantages. I don't think there's much support for TSS-based task-switching outside the i386-proper architecture, e.g. x86-64 doesn't support it.
AFAIK, h/w task-switching has never been used in real operating systems.

14 Apr 2011, 10:13

BOTOKILLER

Joined: 07 Jan 2011
Posts: 154
Location: Ukraine

BOTOKILLER 14 Apr 2011, 11:15

Quote:

AFAIK, h/w task-switching has never been used in real operating systems.

I'm not in real mode))))

14 Apr 2011, 11:15

ManOfSteel

Joined: 02 Feb 2005
Posts: 1154

ManOfSteel 14 Apr 2011, 13:10

LOL By that I didn't mean real-mode OS, but OS IRL (in real life), such as Windows, the Linux kernel, *BSD, etc. All these use software task-switching and have only one TSS per CPU. That has always been the case AFAIK.

14 Apr 2011, 13:10

neville

Joined: 13 Jul 2008
Posts: 507
Location: New Zealand

neville 14 Apr 2011, 20:00

ManOfSteel wrote:

[H/W multitasking] It's a bit slower than s/w multitasking, has a lot more overhead and provides no real advantages.

With multi-core CPUs we now have the ability to implement truly simultaneous H/W multitasking which must be a lot faster than any time-division S/W multitasking Wink

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14 Apr 2011, 20:00

BOTOKILLER

Joined: 07 Jan 2011
Posts: 154
Location: Ukraine

BOTOKILLER 15 Apr 2011, 11:20

neville wrote:

ManOfSteel wrote:
[H/W multitasking] It's a bit slower than s/w multitasking, has a lot more overhead and provides no real advantages.
With multi-core CPUs we now have the ability to implement truly simultaneous H/W multitasking which must be a lot faster than any time-division S/W multitasking

yeah, you are right)

ManOfSteel wrote:

LOL By that I didn't mean real-mode OS, but OS IRL (in real life), such as Windows, the Linux kernel, *BSD, etc. All these use software task-switching and have only one TSS per CPU. That has always been the case AFAIK.

ouch(, havent read atentively, sorry

15 Apr 2011, 11:20

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