[Info-vax] Working with broken hardware, was: Re: DECnet Phase IV broken after VSI update

[kemain.nospam at gmail.com]

>-----Original Message-----
>From: Info-vax <info-vax-bounces at rbnsn.com> On Behalf Of Simon Clubley
>via Info-vax
>Sent: November-06-21 5:42 PM
>To: info-vax at rbnsn.com
>Cc: Simon Clubley <clubley at remove_me.eisner.decus.org-Earth.UFP>
>Subject: [Info-vax] Working with broken hardware, was: Re: DECnet Phase IV
>broken after VSI update
>
>On 2021-11-06, Robert A. Brooks <FIRST.LAST at vmssoftware.com> wrote:
>>
>> Unless they are referring back to the mid-90's when the early PCI
>> Ethernet adapters on Alphas were not-so-great, that info is a bit stale.
>>
>> VMS Engineering (specifically, the guy who's been writing our Ethernet
>> drivers for over 30 years) has stated that auto-negotiate should always
be
>used.
>>
>> If it doesn't work, he'll fix it, or determine that the switch is
>> non-conforming to the standard.
>>
>
>That's a very interesting way of expressing that and leads to a more
>interesting general question:
>
>Does VMS support hardware which doesn't correctly implement a standard
>(by implementing a workaround as Linux tends to do), or has VMS Engineering
>over the decades outright said that it doesn't follow the standards, so
it's
>broken, so we won't support it ?
>
>If it's the latter, is that going to change for x86-64 VMS, given some of
the
>hardware out there ?
>
>Simon.
>
>--

FWIW .. its still an industry problem (even today) - same issue on Linux and
Windows and Telecom gear in general platforms with old(er) switches and gear
that do not conform to todays standards.

Just google "auto-negotiation problems" ..

Sample - 
<https://knowledge.broadcom.com/external/article/167467/why-am-i-getting-aut
onegotiation-problem.html>
"Auto-negotiation problems are common; they result from errors on the
Ethernet devices connected to the appliance, causing dropped packets,
reduced throughput, and session drops. Devices that are connected, such as
the router or a LAN switch could also switch from full-duplex to half-duplex
(and vice versa) because of auto-negotiation problems, resulting in poor
network performance. 

In some cases, if a duplex mismatch occurs when the interface is
auto-negotiated and the connection is set to half-duplex, or the
auto-negotiation does not provide the optimal outcome. As a result, manually
setting the duplex setting might be the workaround to avoid this problem."

Since it is likely impossible for a host driver to be able to detect all
related issues (especially in X86 world), I would suggest the driver do a
small internal test and if it detects an issue, simply log the issue on the
console or host error log / event viewer. 

Regards,

Kerry Main
Kerry dot main at starkgaming dot com






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