On Sun, 19 Dec 1999, Ernest N. Wilcox Jr. wrote:
> First there is the reason Linux is so difficult for the new user. Linux does
> not try to support all hardware combinations imaginable, and it only installs
> support for what is really needed on the system (I'm guessing here).
Yah also linux handles hardware communication more efficiently than win. Lots o' 1s
and
0s get lost in Windows's software layer between the main OS and the hardware,
which i suspect is also one of the reasons Windows is so bloated. I mean it's
alot easier to just open a file and then write out data to the open file
descriptor (as linux does) rather than talking to a driver which in turn
interprets that to the hardware. . .there's a great description of device file
handling in Linux Programming Unleashed if anyone wants more specifics. . .
> Second and I suspect the real reason for stability is the fact that Linux
> starts in "protected mode" and remains there throughout the session, while
> Windows 9x starts in "real mode", then switches to "protected mode" when it
> starts the GUI. But then at the same time, DOS is still running in "real mode"
> underneath the rest of Windows 9x - which is operating in protected mode?!
Actually the way windows uses processor states is really loopy (big
surprise eh?). It's like. . .it starts in v86, then dips into pmode long
enough to activate pmode memory addressing, then falls back into v86 mode. So
its like. . .running DOS but being able to see all the memory without an
ems/xms driver. So we're doing a really phased out hybrid of 20 bit addressing
and 32 bit addressing, in which case im pretty sure preemptive multitasking is
not possible. That in mind, when you run multiple apps under windows, you
essentially have a bunch of things floating around in this one big shared
memory/resource pool. Inevitably, some of them are going to request
resources that are unavailable, ie an in use memory space, or request the
services of an already in use library or something like that. Under ideal
circumstances windows will just say oops cant do that and wait till the
resource is open, but as we all probably know, that usually doesnt happen.):
The AMD K6 Multimedia Technology Manual has a really good write up on
different multitasking environments. Also one of the guys from the demogroup
Triton wrote a really neat paper on pmode memory access under v86 mode. . .i think its
somewhere on scene.org if anyone wants to read up on that. Windows also manages
virtual machines really strangely. It will actually start up VMs in different
processor states, ie it can start one up in pmode, then one in v86 mode
depending on what kind of app is being run. . .probably one of the
reasons that running win3.1 apps under win9x is not really advocated. . .putting
the two together=badness. . .therein being another linux coolness. Since X
isnt in itself another OS, ie its just a separate program, there is no need for
X to set its own machine state up, as windows does. All of linux's VMs are in
pmode.
> Maybe someone can explaine better than I. It just seems to me that Windows is
> going about the thing in too complex a maner, while Linux is doing it the
> simple and elegant way.
>
yah. . .and at the same time its like. . .windows is really specific about what
it needs to run and linux is sorta abstract about things, or i guess
adaptable is a better term. . .its like one of my friends comparison between
Direct3D and OpenGL The developers of OpenGL (sgi) were/are 3D pros who
probably said, "how can we make a really functional open api that displays fast,
stable 3D graphics,will work in a slew of different operating environments, and
is also easy to implement?", whereas the designers of DX/D3D probably said "hmm
we need to figure out how to be able to do fast 3D gfx in Windows so people
will stop writing games in DOS." The result being that sgi turned out a pretty
well built, sleek, easy to use, OPEN api, and MS turned out a rather bloated,
not that easy to use, platform dependent api that does what it needs to and
nothing else. I mean over in the windows world we'er all ooing and ahhing
about the fact that DX7 has hardware T/L but OpenGLs had it forever. to go
off on a tangent, its like that great scene in firebirds where Nick Cage and
Tommy Lee J are in the chopper doing a simulated night time flight and Cage is
pretty much chowing. Cage says "im doing it' im doing it!!" and Tommy L
replies "yeah but youre doing it ugly."
.. . .although i gotta say id love to see Cubase for linux. . .
--
Seth Gibson
Co-Founder/Moderator, Beginner's OpenGL Programming Site/List
"We Support The Newbie Linux3d Project!"
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