Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!fluke!ssc-vax!uvicctr!sdean1
From: sdean1@uvicctr.UUCP (Steven A. Dean)
Newsgroups: comp.sys.amiga
Subject: Re: AppleTalk, Networking, Amigas and Offices
Message-ID: <392@uvicctr.UUCP>
Date: 24 Apr 88 00:57:30 GMT
References: <8804180638.AA23679@cory.Berkeley.EDU> <655@cernvax.UUCP>
Reply-To: sdean1@uvicctr.UUCP (Steven A. Dean)
Organization: University of Victoria, Victoria B.C. Canada
Lines: 37
Keywords: Network speed 500KBaud
Summary: Pardon me?  192KBits?  uh... no.

In article <655@cernvax.UUCP> zofka@cernvax.UUCP () writes:
[stuff deleted...]
>>	It's actually easier than that.  All you really need to do 
>>is get some open collector drivers (IEEE-488 style) and connect them to
>>				-Matt
>   Not so easy at all, look at max speed of the amiga (192 kbits) and
>   this with 100% cpu time... 230kbits for appletalk and with alittle
>   card, something like 10% cpu (or less) Few more $$ but more efficient.
>				 Milan (zofka)

Well, let's see here... 192 KBits you say?  Hmm... that's not very much now...
if I do my math here I get some interesting figures... 

      Processor speed  :    7.16 MHz.
      Mem Wait States  :       0 (for a workbench screen)
      Time for a move  :      12 cycles (move.b  (a0),(a1)+)
      Time for a dbra  :      10 cycles (dbra    d7,loop)
      Total CPU time   :      22 cycles per byte.

      7,160,000 / 22 = 325,413 BYTES per second.  

Well, we all know that those speeds are pretty hairy and would require the
entire system to go dead... but I can't see it being too difficult to get about
100K per second... A friend of mine got (with some UGLY code) about 500KBaud.
The serial port is pretty quick...  
 
BTW, does anyone know how fast data can be pushed through the parallel port
with any reasonable amount of efficiency?  I've never played with it... It 
might be an idea to see how well it can grab data.

Steve
--
Steven A. Dean
sdean1@uvunix.BITNET
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