Path: utzoo!attcan!lsuc!maccs!beame
From: beame@maccs.dcss.mcmaster.ca (Carl Beame)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: PC/TCP speed
Message-ID: <2742AF8F.813@maccs.dcss.mcmaster.ca>
Date: 15 Nov 90 15:09:03 GMT
References: <302@srchtec.UUCP>
Organization: McMaster University, Hamilton, Ontario, Canada
Lines: 34

In article <302@srchtec.UUCP> mra@srchtec.uucp (Michael Almond) writes:
>Does anyone know if PC-NFS (Sun Microsystems) runs faster than PC/TCP
>(FTP Software, Inc.)?  We are testing out a copy of PC/TCP and it runs/access
>files from our Ultrix system slower than our current 3COM server.  I thought
>NFS would be at least as fast as anything written by a company that does
>DOS software.
>
>
>---
>Michael R. Almond (Georgia Tech Alumnus)           mra@srchtec.uucp (registered)
>search technology, inc.				        emory!stiatl!srchtec!mra
>Atlanta, Georgia                                         (404) 441-1457 (office)
>[search]: Systems Engineering Approaches to Research and Development

There is a reason why NFS is slower then 3Com. Basically 3Com 
protocols and structures are designed sepcifically for the DOS environment.
As an example under 3Com a read request is made for a large number of bytes,
the 3Com server sends many packets to the client at a speed which the remote
client can receive all of them. Under NFS, the servers sends data as fast as
possible and the dumb ethernet cards of the PCs can't receive the packets
fast enough and lose some, causing ALL of the packets to be retransmitted.
Also the maximum read size is 8K.

One reason for the difference in speed is the amount of data that can be
read or written at one time and wether or not the data is checksummed.
All PC based NFS packages checksum the incoming data (I hope!).

	PC-NFS uses 8K unchecksummed writes and 1K reads
	InterDrive uses 1K checksummed writes and 1K reads
	BWNFS uses 8k checksummed writes and up to 8K reads

- Carl Beame
  Beame@McMaster.CA