spc restarts

Ben Lindstrom mouring at eviladmin.org
Mon Feb 27 04:09:42 EST 2012

On Feb 26, 2012, at 9:02 AM, Mark Anderson wrote:

> I was wondering why scp didn't have a restart-in-the-middle
> option when transferring a large file.  Isn't that something
> that is supported by the underlying ssh protocol?  Is there
> some other program that can give me this functionality ?

Scp came from rcp.. Which is a stupid simple(ish) protocol
more like doing:  tar -cvf | ssh tar -xvf.  So it really has nothing
to do with the ssh protocol itself as it just needs a streaming
socket to throw data at.

I suspect you're thinking sftp service, and that could be easily 
extended to support it.  I did a cheap proof of concept that 
required adding an sha1 hash request extension to the server 
so I could determine where I needed to pick up in the transfer.  
It really was an attempt to implement a simplified rsync over sftp.

However, that code is long since dead and burned.

- Ben

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