Re: How does Ethernet device know address of transfer buffer
High,
On Wed, 7 Nov 2001 descdata@att.net wrote:
> Hi,
>
> I can successfully install the 3c905 Ethernet driver,
> but I don?t know why it works. This proves I don?t know
> what is going on. I hope that someone can offer some
> light.
>
> I use install parameters ?irq=11" and I don?t set an io
> address. If I try fill in the address e.g. ?io=0x220" I
> receive an error the param_io is invalid.
>
> Don?t the irq number and the address of the buffer go
> together? Doesn?t the os put data in a buffer before
> sending, and then make in interrupt to tell the hardware
> to come get it?
>
> Can someone tell me where the buffer is and how linux
> and the hardware agree on its address?
>
The 3c905 is a pci card, so you do not need to give an irq either. At
computer bootup, the BIOS generates a database of the hardware installed
and assignes irq's and io addresses to the hardware installed in your
computer. This is done before any OS starts. Linux uses this bios database
to set up its hardware. If you want to see more information about your pci
cards, just do a 'cat /proc/pci'. /proc/interrupts and /proc/ioports give
also a lot of information.
That is how it works roughly, I am not sure about details.
Greetz,
Sebastiaan
--
NT is the OS of the future. The main engine is the 16-bit Subsystem
(also called MS-DOS Subsystem). Above that, there is the windoze 95/98
16-bit Subsystem. Anyone can see that 16+16=32, so windoze NT is a
*real* 32-bit system.
>
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