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Re: DECstation ESAR checksum?

Subject: Re: DECstation ESAR checksum?
From: Richard van den Berg <>
Date: Sat, 26 Sep 1998 18:12:26 +0200 (MET DST)
In-reply-to: <>
On Sat, 26 Sep 1998, Thomas Bogendoerfer wrote:

> On Fri, Sep 25, 1998 at 08:00:46PM +0200, Richard van den Berg wrote:
> > Is there someone able to tell how the checksum of the Ethernet Station
> > Address ROM is calculated? This is the ROM layout with 'ba' being the
> > base address of the ROM:
> I've checked my AMD manuals and couldn't find an exact algorithm for doing it.
> And as you can't attach the address prom directly to the lance and c-lance
> like it's possible with the PCnet chips, it's probably up to the hardware
> designer how to calculate the checksum.

The only place where verification of the checksum is mentioned is in the
hardware maintenance guide in the base system tests section. Allthough
the prom layout is mentioned in several DEC docs.
> FYI, the pcnet has 16 bytes of address prom. 0 to 5 are the address octets,
> 6 to 11 is unused, 12 (LSB) and 13 (MSB) is the checksum, 14 and 15 should 
> be 0x57. The checksum is calculated over 0 to 11, 14 and 15.
Thanks, I've been puzzling on it but can't figure the checksum for the
DEC out.

BTW, do you know if there is such a thing as initializing a network driver
The Right Way (tm)? In the network code I've come across several methods,
and comments at checks for bad methods.



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