Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83 (MC840302); site daab.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!genrad!panda!talcott!harvard!seismo!mcvax!enea!daab!lasse
From: lasse@daab.UUCP (Lars Hammarstrand)
Newsgroups: net.unix-wizards
Subject: Drive/Device driver performens
Message-ID: <160@daab.UUCP>
Date: Fri, 13-Sep-85 13:02:52 EDT
Article-I.D.: daab.160
Posted: Fri Sep 13 13:02:52 1985
Date-Received: Wed, 18-Sep-85 02:39:47 EDT
Reply-To: lasse@daab.UUCP (Lars Hammarstrand)
Organization: Datorisering AB, Stockholm, Sweden
Lines: 31


	Hello "net folks" !

Here you all have a real brain training problem.

Let's say that you have two different disk drives, one is a STDC whith
DMA transfer to main memory and the other one is a SMD drive but with a very
slow (programmed IO) transfer to main memory, in other words, it has to
pick each byte from the controller one by one from a data-port instead of
transfer it with DMA as in the STDC controller.

Now the problem: 
----------------
How can you measure witch one is faster than the other one in real life?,
and how can you measure the efficiency of the divice driver ?
I mean can you put it black on white in some way?.

One way to test it (that I have done), is by copying a lot of data (a cptree)
from one device to the other and so on with the time command, but it didn't
give me any bigger difference between the drives!. I'm running a Cromemco
SysVr2 machine with a UniPlus+ port.

Tanks in advance:

	Lars Hammarstrand.
	Datorisering AB, Stockholm, SWEDEN.

	UUCP:	{seismo,decvax,philabs}!{mcvax,ukc,unido}!enea!daab!lasse
	ARPA:	decvax!mcvax!enea!daab!lasse@berkley.ARPA
		decvax!mcvax!enea!daab!lasse@seismo.ARPA


Brought to you by Super Global Mega Corp .com