Slow performance copying large files from OES server

  • 7021903
  • 28-Sep-2017
  • 05-Oct-2017


Client for Open Enterprise Server 2 SP4 (IR4)
Client for Open Enterprise Server 2 SP4 (IR5)
Client for Open Enterprise Server 2 SP4 (IR6)


Slow performance when copying files from an OES server to the local workstation.
Normal performance when copying files to an OES server from the local workstation.


Fixed in Client for Open Enterprise Server 2 SP4 (IR7)


With Client for OES 2 SP4 (IR4 - IR6), when copying a file from an OES server, only the first NCP 'Read File' request from the Client for OES is 87,72 and all subsequent NCP 'Read File' requests are 87,64, which results in slow performance when copying a large file from the OES server. The difference in performance by using NCP 87,64 instead of NCP 87,72 for reading a large file becomes more obvious when the size of the file to be copied is larger and/or when the network connection between the workstation and server is slower.

Additional Information

Note that even on servers which do support NCP 87,72, it is not expected that NCP 87,72 will be used for every read request.  The fix in Client for OES 2 SP4 (IR7) corrects the problem where the Client should have continued using NCP 87,72 but was unnecessarily falling back to NCP 87,64.  But there are still cases where we expect to see the Client correctly use NCP 87,64 instead of NCP 87,72. The Client is designed to give the best performance for both large data transfers which can be accomplished with a single NCP request/reply, and for application requests which fit within the NCP 87,64 limitation (i.e. 64KB or less). 

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