BIOS and divce driver & Interrupt handler?

Hi,

Communication with the bios (and in fact with DOS too) by so called
interrupt routines.

The interrupt vector table must be set up by the bios for this to work.
Basically what happens is that in a certain part (the lowest part) of memory
a table is created. This table consists of address in the bios where a
certain routine start (for instance to output text to your screen, or to
send something to the printer port).

Now when a program wants to clear the screen for instance, it could do it as
follows

xor ah,ah ; Clear the ah register (this will make ah 0 which means call the
function to change graphics mode)
mov al,6 ; Select 640*200 color graphics mode
int 0x10 ; Call the bios function

The ah always contains the function number (which a programmer should just
know). Other registers contain additional data. Then the function is called
by using an interrupt.

Regards Ron AF Greve.

"leza" wrote in message
le.rogers.com...
I am reading about the BIOS and the article says the following
----------------
quote
When you turn on your computer, the BIOS does several things. This is its
usual sequence:
1.. Check the CMOS Setup for custom settings
2.. Load the interrupt handlers and device drivers
3.. Initialize registers and power management
4.. Perform the power-on self-test (POST)
5.. Display system settings
6.. Determine which devices are bootable
7.. Initiate the bootstrap sequence
/end quote
-----------------

My question, in point #2,
1) BIOS load the interrupt handlers? where are these handlers? are they
software?
2) are the device drivers part of the BIOS?? if not where are they? how
the
BIOS loads them??

On Sat, 05 Jul 2003 17:02:04 GMT, "leza"
wrote:

I am reading about the BIOS and the article says the following
----------------
quote
When you turn on your computer, the BIOS does several things. This is its
usual sequence:
1.. Check the CMOS Setup for custom settings
2.. Load the interrupt handlers and device drivers
3.. Initialize registers and power management
4.. Perform the power-on self-test (POST)
5.. Display system settings
6.. Determine which devices are bootable
7.. Initiate the bootstrap sequence
/end quote
-----------------

My question, in point #2,
1) BIOS load the interrupt handlers? where are these handlers? are they
software?
These are BIOS interrupts, such as video, keyboard, and disk interrupt
routines.

2) are the device drivers part of the BIOS?? if not where are they? how the
BIOS loads them??
I assume they're referring to basic device drivers used to access the
hardware such as video, keyboard, disk, etc.