9. Real-time UNIX executables

While historically the world of real-time was reserved for general-purpose executables, in the 1980s players from the UNIX world began to take an interest in this field. Indeed, as application domains grew, for many applications the advantages of a UNIX interface could outweigh the disadvantages, to the extent that certain real-time features could be obtained.

Two main approaches were followed:

• one in line with the POSIX standard: this consists of enriching the standard with services adapted to real time ;

• the other, later, in the Linux movement. The latter can again be divided into two approaches:

  • that of making the kernel pre-emptive, thus providing real-time reaction capabilities for applications,

  • using a real-time...