[BYTEIO-WG] Notes from the OGSA ByteIO session at OGF19

[Andre Merzky]

Hi Neil, 


Quoting [Neil P Chue Hong] (Jan 31 2007):
> 
> Notes from OGSA-ByteIO Session at OGF19, Chapel Hill
> ====================================================
> 
> [...]
> 
> With GridFTP, because of the lack of partial transfer you could implement
> something in which the first time you talk to the service, you get sent
> back information to gridftp the whole thing (file?), then store it locally
> and access chunks back on client - could implement this but it is a silly
> way to do it. Basically GridFTP is targetted to moving the whole chunk of
> data, whereas ByteIO targetted to being cleverer at getting just the bytes
> it needs.

Maybe I am missing something here, but GridFTP as protocol
_does_ support partial file access, doesn't it?   It is not
implemented in all GridFTP servers though AFAIK.

The spec says (I may not have the latest version though,
will check):

  All implementations of this specification SHOULD implement
  the following Partial File Transfer ERET module:
  
    ERET <SP> PFT="<offset>,<length>" <filename>
  
    offset::= string representation of a positive 64 bit integer
    length::= string representation of a positive 64 bit integer
  
  Note that the offset specified here is the offset in the
  file and is not related to the offset specified in the
  MODE E header, which is the offset in the transfer over
  the wire.


Cheers, Andre.


-- 
"So much time, so little to do..."  -- Garfield