>Number:         2176
>Category:       port-i386
>Synopsis:       incomplete ed.4 man page
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Tue Mar  5 22:05:01 1996
>Last-Modified:
>Originator:     John M Vinopal
>Organization:
The Wailer at the Gates of Dawn            /   banshee@resort.com          |
Just who ARE you calling a FROOFROO Head? /                                |
DoD#0667  "Just a friend of the beast."  | http://www.resort.com/~banshee/ |
2,3,5,7,13,17,19,31,61,89,107,127,521,607....\      Port and Absinthe      |
>Release:        1.1
>Environment:
System: NetBSD gabriella.resort.com 1.1A NetBSD 1.1A (GABRIELLA-NCR) #0: Sun Feb 4 16:16:19 PST 1996 banshee@gabriella.resort.com:/usr/local/NetBSD/src/sys/arch/i386/compile/GABRIELLA-NCR i386

>Description:
	People are often confused and dismayed by 3c503 cards.  While
	their poor taste in hardware is their own problem, we can apply
	a nice coat of gloss.  The base of this text appeared on usenet
	recently, and is apparently part of the original driver release
	documentation.  While there are other diagnostic messages, this
	is the most common.
>How-To-Repeat:
>Fix:
*** /usr/src/share/man/man4/man4.i386/ed.4      Fri Oct 13 18:28:52 1995
--- ed.4        Tue Mar  5 18:21:31 1996
***************
*** 57,62 ****
--- 57,97 ----
  .It Novell NE1000
  .It Novell NE2000
  .El
+ .Sh DIAGNOSTICS
+ The DP8390 Ethernet chip implements a shared-memory ring-buffer
+ to store incoming packets.  When this buffer overfills, the 
+ .Nm
+ driver produces a message similar to the following:
+ .Pp
+ .Bl -tag -width -offset indent -compact
+ .It ed1: warning - receiver ring buffer overrun
+ .El
+ .Pp
+ The 16bit boards (8013 series) have 16k of memory as well as
+ fast memory access speed.  Typical memory access speed on these
+ boards is about 4MB/second.  These boards generally have no
+ problems keeping up with full ethernet speed and the ring-buffer
+ seldom overfills.
+ .Pp
+ However, the 8bit boards (3c503, and 8003) usually have
+ only 8k bytes of shared memory.  This is only enough room for about
+ 4 full-size (1500 byte) packets.  This can sometimes be a problem,
+ especially on the original WD8003E and 3c503, because these
+ boards' shared-memory access speed is quite slow; typically
+ only about 1MB/second.  The
+ overhead of this slow memory access, and the fact that there is
+ only room for 4 full-sized packets means that the ring-buffer
+ will occassionally overrun.  When this happens, the board must
+ be reset to avoid a lockup problem in early revision 8390's.
+ Resetting the board causes all of the data in the ring-buffer
+ to be lost, requiring it to be retransmitted/received, congesting
+ the board further.  Because of this, maximum throughput
+ on these boards is only about 400-600k per second.
+ .Pp
+ This problem is exasperated by NFS because the 8bit boards lack
+ sufficient memory to support the default 8k byte packets that NFS and
+ other protocols use as their default.  If these cards must be used
+ with NFS, use the NFS -r and -w options to limit NFS's packet size.
+ 4096k byte packets generally work.
  .Sh SEE ALSO
  .Xr ifconfig 8 ,
  .Xr intro 4 ,

>Audit-Trail:
>Unformatted: