Return to PROB_REP CVS log

Up to [Power 6/32 Unix Tahoe 4.2BSD] / cci / d / ether

Power 6/32 Unix version 1.2b

COMPUTER CONSOLES INC.				INTER-OFFICE MEMO
-----------------------------------------------------------------

						Jan 7th, 1985


TO:	  Naresh Desai

FR:	  Pham, Phuc M.

SUBJECT:  Report of Ethernet Controller Diagnostic Problems.


	Following are the problems of the ethernet controller
functionality that I found while trying to develop a diagnostic
program for it.


	1. In loop 2 mode, the rbc of the receiver buffer are
	   not updated to reflect the length of the buffered
	   message, but instead, the crs (the first word of the
	   receive buffer) always contains a value of 0xB000.
	   This causes the error-checking mechanism to generate
	   the following errors even though the message is corr-
	   ectly received.

		- CRC error
		- Underrun error (because rbc = 0)
		- Oddbit error

	2. In loop 3 mode, the crs word of the receive buffer
	   always contains a value of 0xA000 which, again,
	   causes the error checking mechanism to generate CRC
	   and underrun errors for every message transmitted.
	   Moreover, as seen in the attached sample run, no mess-
	   age has shown up in the receive buffers. 

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.