What is 1.0 courier?

Courier 1.0, formally defined in RFC 991, is a remote procedure call (RPC) protocol developed by Xerox in the early 1980s. It served as a foundational technology in the development of distributed computing.

Key aspects of Courier 1.0 include:

• Purpose: It was designed to facilitate communication between different programs or services on a network, enabling them to call procedures or functions on each other as if they were local.

• Data Types: Courier defined a set of standard Data%20Types for representing common data structures like integers, strings, and arrays. These were machine-independent, enabling interoperability between systems with different architectures.

• Procedure Calls: The protocol specified how to encode Procedure%20Calls and their parameters for transmission over the network, as well as how to handle return values and errors.

• Error Handling: Courier included mechanisms for handling errors that occurred during remote procedure execution. These mechanisms allowed clients to detect and respond to failures in a robust manner.

• Usage: It saw use in various Xerox products, particularly in applications involving network services and distributed printing. It influenced later RPC protocols.

• Limitations: While innovative for its time, Courier 1.0 had limitations, including a relatively complex specification and certain restrictions on data type flexibility. Later RPC systems addressed these limitations.