BIB-VERSION:: CS-TR-v2.0
          ID:: STAN//CS-TR-86-1134
       ENTRY:: May 01, 1995
ORGANIZATION:: Stanford University, Department of Computer Science
       TITLE:: UIO: A Uniform I/O System Interface for Distributed Systems
        TYPE:: Technical Report
      AUTHOR:: Cheriton, David R.
        DATE:: November 1986
       PAGES:: 32
    ABSTRACT:: A uniforrn I/O interface allows programs to be written
               relatively independent of specific I/O services and yet work
               with a wide variety of the I/O services available in a
               distributed environment. Ideally, the interface provides this
               uniform access without excessive complexity in the interface
               or loss of performance. However, a uniform interface does not
               arise from careful design of individual system interfaces
               alone; it requires explicit definition.

               In this paper, we describe the UIO (uniform I/O) system
               interface that has been used for the past five years in the V
               distributed operating systems, focusing on the key design
               issues. This interface provides several extensions beyond the
               I/O interface of UNIX, including support for record I/O,
               locking, atomic transactions and replications as well as
               attributes that indicate whether optional semantics and
               operations are available. We also describe our experience in
               using and implementing this interface with a variety of
               different I/O services plus the performance of both local and
               network I/O. We conclude that the UIO interface provides a
               uniform I/O system interface with significant functionality,
               wide applicability and no significant performance penalty.
       NOTES:: [Adminitrivia V1/Prg/19950501]
         END:: STAN//CS-TR-86-1134