Re: 10 Mbps and 100 Mbps ISA cards

On Mon, 3 Nov 2003, Miguel Gonz=E1lez Casta=F1os wrote:

>  I have a 486 working as a router using linux RedHat 7.3. It has two
> 3Com ISA cards, a Etherlink Fast 100 Mbps (driver 3c515) and Etherlink
> III 10 Mbps (driver 3c509).
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>  The router is connected to a cable modem through the 10 Mbps ISA card
> and the other one interfaces with a switch-hub to the LAN.
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>  I am considering if due to the limits of the bandwidth of the ISA bus
> if it really is worth to have a 100 Mbps to the LAN interface in the
> 486.

No, it's not.

> If I use that 100 Mbps ISA i.e. in a Pentium III the performance
> would be similar to a PCI NIC?

Not at all.
Even the worst $5 10/100 PCI NIC is far better than any ISA device.

>  I am having problems to configure the parameters in the monolithic
> kernel for using the two NICs in the /etc/lilo.conf because the system
> detects the 3c509 card, but not the 3c515. What is funny is that If I
> boot using modules, it uses isapnp, I cant make them work either, but i=
f
> I reboot to the monolithic kernel then It suddenly appears to detect th=
e
> 3c515. If I shutdown and boot again the monolithic kernel, says that no
> 3c515 card found...I=B4m stumped.

This is a ISA-PnP bug in the kernel -- there is a PnP reset sequence
that needs to be sent correctly.

>  Anyway I dont know if the 3c515 is trying to use the wrong IRQ. When I
> succeed to recognize the 3c515 card (using the trick of booting the
> modular kernel first), it seems that IRQ 10 is fine, but uses the DMA 3
> channel...Is this right?

It's whatever IRQ and DMA channel is assigned by the PnP code.

The 3c509 has a non-PnP activation mode that uses the IRQ and I/O from
the EEPROM.  Otherwise it uses the ISA-PnP assigned values.

--=20
Donald Becker				[email protected]
Scyld Computing Corporation		http://www.scyld.com
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