TOPIC:    ACCESSING DISKS OVER A NETWORK



          RVD (Remote Virtual Disk Protocol) is a communications protocol
          that enables hosts to read data from, and write data to, secon-
          dary storage over a data network.  It differs from traditional
          "file" servers in providing page-level access to raw disks.  In
          our most commonly used implementation (both server and clients
          running under Berkeley 4.2 UNIX* on VAX 11/750's), performance
          under typical usage patterns is comparable to a locally con-
          nected RK07.

          This talk relates some of the issues we considered, and lessons
          we have learned, in designing and implementing RVD.  I will dis-
          cuss the choice of a remote disk, as opposed to a remote-file,
          protocol, trace the development of flow-control in RVD, and talk
          about some design decisions in the server that strongly affected
          overall performance of this implementation.