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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Release1.0Requirements" by DougCutting
Date Wed, 08 Oct 2008 17:41:36 GMT
Dear Wiki user,

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The following page has been changed by DougCutting:

  ''Language Neutral - yes it will mean duplicated client-side and hence more work. From what
I have observed in the design discussion,  keeping the client side small was a criteria because
we were expecting language neutral protocols down the road. Do you feel that we should not
bother with language neutral protocols at all? --SanjayRadia''
+ ''I think we should be very careful about which network protocols we publicly expose.  Currently
we expose none.  I do not think we should attempt to expose all soon.  A first obvious candidate
to expose might be the job submission protocol.  Before we do so we should closely revisit
its design, since it was not designed as an API with long-term, multi-language access in mind.
 Any logic that we can easily move server-side, we should, to minimize duplicated code.  Etc.
 The HDFS protocols will require more scrutiny, since they involve more client side logic.
 It would be simpler if all of HDFS was implemented using RPC, not a mix of RPC and raw sockets.
 So we might decide to delay publicly exposing the HDFS protocols until we have made that
switch, should it prove feasable.  I think we could reasonably have a 1.0 release that exposed
none.  I do not see this as a gating issue for a 1.0 release.  We could reasonably expose
such protocols in the course of 1.x releases, no?  
  === Versioning Scheme - Manual or Automated ===
  Hadoop is likely to see fairly significant changes between 1.0 and 2.0. Given the compatibility
requirements, we need some scheme (manual or automated) for versioning the RPC interfaces
and also for versioning the data types that are passed as parameters to rpc.

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