C&T vga - newbie quests

[John van Vlaaderen]

Thanks Peter, but... maybe i should have said:

...In relation to LinuxBIOS...

We know what X and a vgabios are -- what I am asking about are 
references on this mailing list to writing X into a vgabios -- maybe 
VIA -- using code from the bochs vgabios -- or something like that -- 
along w/ Xfree86

Framebuffers are new to me, never really thot about them, I am looking 
of DirectFB right now and it really seems like an acceleration process, 
so I  am wondering why it keeps appearing in LinuxBIOS mailing lists.

What is envisioned for getting X running from LinuxBIOS ??  Clusters 
obviously have no need for them, but there are huge hungry embedded 
people out there.  I would like to join the fray with some useful 
information.

Only part of the need is being kewl, the more important issue becomes 
getting proprietary code out of the PC completely, as dictated by the 
GNU religion, and gaining support among the youth.








On Thursday, January 23, 2003, at 08:11 PM, Peter Stuge wrote:

> On Fri, Jan 24, 2003 at 01:14:53PM -0500, John van Vlaaderen wrote:
>> I am writing a glossary right now and I need to know the difference
>> between:
>>
>> vgabios, framebuffer and X
>
> Wow, ok, not that this is the best place, but ok.
>
> LinuxBIOS is currently mostly operational on what's commonly referred 
> to as
> the PC platform.  The last standardized graphics controller on this 
> platform
> was the VGA. (Video Graphics Array)  This VGA card had a BIOS that would
> initialize the card when the main system BIOS traversed all expansion 
> cards
> looking for any BIOSes on them.
>
> The VGA BIOS knows the details of how to program the graphics card.  
> The VGA
> BIOS is closely tied to every single hardware.  Different graphics 
> chipset -
> different VGA BIOS.  Graphics chipset makers are often reluctant to 
> release
> detailed programming information for their chipsets, but a VGA BIOS is
> always included with the card.  So if LinuxBIOS can make use of the VGA 
> BIOS
> it is trivial to use the computer screen e.g. for startup debugging.
>
> 'framebuffer' has a couple of different meanings.  One is the video 
> memory
> on the graphics card.  Another is the Linux drivers for accessing the 
> said
> memory.  Writing a Linux framebuffer driver requires the same detailed
> programming information as for a VGA BIOS.  Framebuffer drivers aren't 
> all
> that common, it has become sort of a niche, used frequently for 
> Set-Top-Box
> and other embedded systems.  (Reference: DirectFB.)  Think of the
> framebuffer drivers as a VGA BIOS in Linux for Linux, it allows Linux to
> know all (or at least a lot) about the graphics controller in the 
> system.
>
> X is usually short for X-Windows which is the windowing system providing
> core GUI functionality in almost all available Unix systems.  When open
> source people say X or X server they're often talking about XFree86, an 
> open
> source X-Windows server.  The X server also needs detailed knowledge 
> about
> graphics chipsets, in order to provide and perform the desired 
> functions in
> an efficient manner.
>
>
> Short summary:
>
> The VGA BIOS, a framebuffer driver and the X server all need detailed 
> info
> on programming the graphics controller.  They differ in whom they 
> provide
> services for.
>
> The VGA BIOS provides services mainly meant for MS-DOS and
> other "classical" textmode applications like LILO and Linux itself.
>
> The framebuffer driver provides services mainly meant for Linux and is 
> also
> a part of Linux.
>
> The X server provides services to X clients and/or the window manager.  
> All
> programs run in X are X clients.
>
>
> Hope this clears it up.
>
>
> //Peter
>
>
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