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From: gandrews@netcom.COM (Greg Andrews)
Newsgroups: comp.sys.3b1
Subject: XMODEM file padding (was Re: UMODEM on local connections)
Summary: XMODEM pads the file.
Keywords: UMODEM XMODEM local
Message-ID: <1991Apr13.014747.7144@netcom.COM>
Date: 13 Apr 91 01:47:47 GMT
References: <1991Apr8.221615.1195@cbnewsj.att.com> <1991Apr9.161637.12059@oswego.oswego.edu>
Distribution: na
Organization: Netcom - Online Communication Services  UNIX System {408 241-9760 guest}
Lines: 19

In article <1991Apr9.161637.12059@oswego.oswego.edu> ostroff@oswego.Oswego.EDU (Boyd Ostroff) writes:
>
>The only problem I've noticed is that there are often a bunch of NULLs 
>appended to the end of the file, as though the two programs couldn't agree 
>on where the file ends...
>

XMODEM doesn't send any file name or file length information to the
receiver, and the data packets are 128 bytes in size, period.

If the file size doesn't match up to an exact multiple of 128 bytes, the
last packet will be only partly full of file data.  The protocol has to
put SOMEthing into the packet to fill it out, and nulls are often used.

-- 
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|  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
|                 |   Internet: gandrews@netcom.COM                      |
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