Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!columbia!cunixc!lih
From: lih@cunixc.cc.columbia.edu (Andrew Lih)
Newsgroups: comp.sys.mac
Subject: Re: Kermit question
Summary: Kermit transfer rates
Keywords: mac kermit transfer
Message-ID: <1630@cunixc.cc.columbia.edu>
Date: 28 Jun 89 14:37:16 GMT
References: <320@umabco.UUCP> <7233@cg-atla.UUCP> <32533@apple.Apple.COM> <3769@viscous.sco.COM>
Reply-To: lih@cunixc.cc.columbia.edu (Andrew Lih)
Followup-To: comp.sys.mac
Organization: Columbia University
Lines: 46

In article <3769@viscous.sco.COM> jamesm@sco.COM (James M. Moore) writes:
>One thing I've noticed about Kermit (using 9(40)) is that the transfer
>rate seems very slow.  I'm running a 9600 baud direct connect to a XENIX
>box, and kermit reports the effective baud rate for file transfers at
>about 1200. Is there any way to get this speed up, or is this just something
>I have to live with? 

One nice thing about version 0.9(40) is that you can adjust the packet
size of the send/receive packets.  Kermit normally uses a packet size
of 94 bytes.  You can significantly increase throughput by doing
several things:

	1.  Increase the packet size.  If you increase the size to
	    a higher byte count (512 bytes or even up to 1024 bytes)
	    more data will be transfered without all of the packet
	    headers as overhead.  This usually gives you the most
	    dramatic increase.

	2.  Adjust the block check accordingly.  MacKermit presently
	    supports three types of block check (1,2,3).  Block check
	    type 1 is a simple checksum, which is the fastest to
	    calculate.  If you have a very clean line (dedicated line,
	    or direct connect) then this is all that you will need.
	    Block check type 3 is a full CRC check, so it will take
	    a while to compute this for each block.  On a Mac Plus
	    there is a noticable slowdown.  Use a higher block check
	    when there is more chance for an error.

	3.  Download to a quick storage medium.  If it is possible,
	    download to a RAM disk, and second to a hard disk.
	    Downloading to a floppy will slow things down
	    since reads/writes to a floppy are rather slow.

If you have a noisy line, then you will want to decrease your packet
size (perhaps no larger than 512 bytes) since retransmission of
anything larger will bog down your file transfer.

Hope this helps!

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 """""""   Andrew "Fuz" Lih	              Columbia University Center
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