MadSci Network: Computer Science

Re: Is it possible to download something in parts?

Area: Computer Science
Posted By: Keith Little, Systems Analyst/Programmer
Date: Fri Jan 10 14:35:16 1997
Message ID: 848785463.Cs


In general, downloads are always accomplished in one session.  To
my knowlege, neither HTTP or FTP support partial downloads.

However, If you have access to a TCP/IP compatible terminal
emulator that supports the ZMODEM protocol, it's possible to do what
you want.  In fact, I download portions of files at different times that
way.  This is the trick:

1) Start your emulator and make sure you select whatever option will
   allow you to KEEP aborted download files.

2) Establish TELNET session with whatever BBS you want to get
   the file from (it has to support Internet TELNET sessions).

3) Select the file for download and use the ZMODEM (with resume)

4) Whenever you want to stop the transfer, hit the "abort" button
   (whichever one is appropriate for your emulator).

5) Exit your emulator.

6) Repeat steps 1 though 5 (at various times) until all of the file
   has been received.

The reason this works is that ZMODEM will restart the transfer each
time at the byte address following the last one received.

Hope this helps, and have a great day!

Keith Little

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