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Article #5998Poor Latency using Digiboard 16em
From: bigdaddy_paul
Date: Thu, 21 Oct 1999 00:00
Date: Thu, 21 Oct 1999 00:00
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1819 bytes
I am attempting to communicate with a number of external devices via 115200 bps async serial connections brought in to an AlphaServer 800 by a Digiboard 16em. The Alpha is running DEC Unix 4.0f. The external devices are polled in a half-duplex manner. Each message (inbound and outbound) is relatively short (In the range of 10 to 250 bytes). The external devices respond to the poll requests with latencies in the range of 2 to 5 milliseconds. However, I am observing latencies in the range of 15 to 30 milliseconds when using getclock to fetch timestamps at the start and end of the exchange. I have set the poll parameter for the Digiboard using Digi's ditty utility to its shortest value of 2000 microseconds. I would be most grateful for any useful suggestions including other hardware that could be used instead of the Digiboard that would perform better (A minimum of 8 ports must be supported with 16 being the preferable value). Paul Wilson Sent via Deja.com http://www.deja.com/ Before you buy.
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 106cd7,404abeb1ba8be574,start X-Google-Attributes: gid106cd7,public X-Google-Thread: fee84,404abeb1ba8be574,start X-Google-Attributes: gidfee84,public X-Google-Thread: 1164f8,404abeb1ba8be574,start X-Google-Attributes: gid1164f8,public From: bigdaddy_paul@my-deja.com Subject: Poor Latency using Digiboard 16em Date: 1999/10/21 Message-ID: <7unj6s$c3v$1@nnrp1.deja.com> X-Deja-AN: 538816021 X-Http-Proxy: 1.0 x42.deja.com:80 (Squid/1.1.22) for client 161.184.135.85 Organization: Deja.com - Before you buy. X-Article-Creation-Date: Thu Oct 21 17:40:45 1999 GMT X-MyDeja-Info: XMYDJUIDbigdaddy_paul Newsgroups: comp.sys.dec,comp.unix.osf.osf1,fa.alpha-osf-managers X-Http-User-Agent: Mozilla/4.01 [en] (WinNT; U)