Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!apple!claris!peirce
From: peirce@claris.com (Michael Peirce)
Newsgroups: comp.protocols.appletalk
Subject: Re: TOPS vs. PublicFolder (was Re: acintosh Peer-to-Peer Communications)
Message-ID: <10880@claris.com>
Date: 15 Feb 90 19:01:30 GMT
References: <3782@accuvax.nwu.edu> <5374@okstate.UUCP> <1990Feb14.184128.738@intercon.com> <741@suntops.Tops.Sun.COM>
Reply-To: peirce@claris.com (Michael Peirce)
Organization: Claris Corporation, Santa Clara CA
Lines: 40

In article <741@suntops.Tops.Sun.COM> cohen@santa_fe.tops.sun.com (Michael Cohen) writes:
>In article <1990Feb14.184128.738@intercon.com> amanda@mermaid.intercon.com (Amanda Walker) writes:
>>example, copying files via TOPS is optimized for LocalTalk, which means it
>                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>doesn't try very hard to push data across any faster.  Public Folder does
>>a better job of pushing the bits across the wire
>
>  I must object to this claim.  The performance of TOPS vs. PublicFolder for 
>copying files has nothing at all to do with whether TOPS is optimized for
>LocalTalk vs. EtherTalk (or IP or TokenRing, etc.).
>  It has to do with the fact that TOPS is a file-sharing product, not a file
>transfer product. Hence TOPS uses a protocol that is optimized for file-sharing,
>namely a request-response transaction oriented protocol, such as ATP.
>  PublicFolder on the other hand is a file-transfer product, so it uses a
>protocol which is optimized for file transfer, namely a stream-oriented
>protocol, i.e. ADSP.

Ahem, Public Folder does not use ADSP.  It uses ATP.  

I agree that TOPS, being a file server, and Public Folder, being a file
transfer utility, are optimized for different operations.  Public Folder
tries to blast files across the network, nothing more.  TOPS must keep
track of lots of different things as files are opened, closed, read, etc.

Of course, this is also why Public Folder takes up so much less memory
that TOPS does...

One other comment about transfer speeds.  Another variable people haven't
mentioned yet is disk speed at each end.  I've noticed that this can make
a big difference for file transfers - especially when using EtherTalk.

 Claris Corp. | Michael R. Peirce (author of Public Folder)
 -------------+--------------------------------------
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