A Service Package Interpreter (SPI) is a software

Computer software

Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....

 module that takes special tasks (Packages) from a generic HTTP

Hypertext Transfer Protocol

The Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web....

 daemon

Daemon (computer software)

In Unix and other multitasking computer operating systems, a daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user...

 and handles them with the help of UI

User interface

The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

 components.

The SPI module usually sits in kernel space as a UI driver from one side, and as an Ethernet

Ethernet

Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

 device at the other side. The SPI then captures network traffic in order to find Package Requests (PR). When it captures one, the HTTP daemon sets up the FLGOT_POST_PACKAGE or FLGOT_GET_PACKAGE. The SPI compares both Ethernet data and HTTP request, interprets them and passes the interpreted data to the UI peripheral.

History

The first SPI prototype created by the M5 Commission, after the overall conclusion pointed about the lake of dynamic interpreter for the HTTP standard.
It became a standard in 1998 by the same M5 Commission.