Resuming a file transfer

Factual Questions
1

does anyoneknow how resuming a file transfer from where it left off actually works?

Chief’s Domain - http://www.seas.ucla.edu/~ravi

2

I might, but you need to specify what you’re talking about more precisely. Resume a file that’s being transferred using what protocol?

If you’re talking about FTP, the protocol includes a REST (restart) command; some (but not all) ftp clients provide access to it. You can read the details in the RFC:

http://www.pmg.lcs.mit.edu/cgi-bin/rfc/view?959

I suppose it just does a seek() on the server according to how much data is already present, and the client just starts appending the new data to what it has already.

If you’re talking about HTTP, I believe there is a range identifier for GET requests. You can find the RFC here:

http://www.pmg.lcs.mit.edu/cgi-bin/rfc/view?number=2068

If you’re talking about something else, like rcp or zmodem or whatever, you’ll have to specify, and maybe I can give a more appropriate answer.

–
peas on earth

3

An additional note regarding FTP resumption: The server also has to support the command, although I grant you that most do at this point…