Xref: utzoo comp.os.vms:22687 comp.sys.dec:2694
Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!tut.cis.ohio-state.edu!mailrus!husc6!frooz!cfa.HARVARD.EDU
From: wyatt@cfa.HARVARD.EDU (Bill Wyatt)
Newsgroups: comp.os.vms,comp.sys.dec
Subject: Re: DEQNA -> DELQA Upgrade
Message-ID: <314@cfa.HARVARD.EDU>
Date: 16 Feb 90 15:34:11 GMT
References: <900215144450.266060db@EQL.Caltech.Edu>
Sender: news@cfa.HARVARD.EDU
Followup-To: comp.os.vms
Lines: 32

>> What exactly does the DELQA "fix" or give you that the DEQNA doesn't have?
[...]
>> to the DELQA.  I know that the DEQNA has never been a fast controller; does
>> the DELQA basically give faster performance or are there problems that it fixes
>> as well?

>      The DELQA supports IEEE 802.3, the DEQNA doesn't.  Phase-V DECnet
> is going to require 802.3 support from the ethernet controller (at least
> for VMS; I don't know about Ultrix).

>      Also, DEQNAs (older, out of rev ones, anyway) require that PEDRIVER
> checksumming be enabled for LAVc's.  This puts more overhead on all the
> CPUs in the cluster.  [Naturally, this doesn't matter to Ultrix sites.]

My understanding (from a knowledgeable person in DEC) is that the
DEQNA isn't all that slow; it got that reputation from poor initial
driver implementations, plus that infamous FCO early on. In fact, the
uVax II cannot feed it at the speed it is capable of. 

However, that's not to say the DELQA isn't a better board, and implements
functions that would be much slower on future systems (as mentioned above).
Apparently the DELQA won't necessarily be faster for uVax II's running
current software.

Bill Wyatt, Smithsonian Astrophysical Observatory  (Cambridge, MA, USA)
    UUCP :  {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt
 Internet:   wyatt@cfa.harvard.edu
     SPAN:   cfa::wyatt                 BITNET: wyatt@cfa
Bill Wyatt, Smithsonian Astrophysical Observatory  (Cambridge, MA, USA)
    UUCP :  {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt
 Internet:   wyatt@cfa.harvard.edu
     SPAN:   cfa::wyatt                 BITNET: wyatt@cfa