This chapter describes a socket based communications interface (SCI) which provides a Berkeley socket style programming interface for VA Smalltalk applications using TCP/IP for communication tasks. The implementation of the socket based communications interface is a subset of those functions available in any typical Unix network programming environment.

Most implementations of this specification will consist of a Smalltalk interface to an existing commercially available TCP/IP package. These packages maintain data structures that represent and manage the sockets. The Smalltalk part of the implementations will have classes and instances that interface to the underlying implementation and in some cases have OS handles and copies of the structures used in these implementations.