Exec (Amiga)

Exec
DeveloperCarl Sassenrath
OS familyAmigaOS
Working stateCurrent
Source modelClosed source
Initial release23 July 1985; 39 years ago (1985-07-23)
Latest release4.1 Final Edition Update 2 / 12 January 2021; 3 years ago (2021-01-12)
Marketing targetAmigaOS
Available inEnglish
Update methodCompile from source code
PlatformsAmiga Motorola 68000 series (MC680x0, 68k)
Kernel typeMicrokernel
Default
user interface
Command-line interface
LicenseProprietary
Official websitewww.amigaos.net

Exec is the kernel of AmigaOS. It is a 13 KB multitasking microkernel which enabled pre-emptive multitasking in as little as 256 KB of memory (as supplied with the first Amiga 1000s). Exec provided functions for multitasking, memory management, and handling of interrupts and dynamic shared libraries.[1][2]

It acts as a scheduler for tasks running on the system, providing pre-emptive multitasking with prioritized round-robin scheduling. Exec also provides access to other libraries and high-level inter-process communication via message passing. Other comparable microkernels have had performance problems because of the need to copy messages between address spaces. Since the Amiga has only one address space, Exec message passing is quite efficient. The only fixed memory address in the Amiga software (address 4) is a pointer to exec.library, which can then be used to access other libraries. Exec was designed and implemented by Carl Sassenrath.[3]

  1. ^ Sassenrath, Carl (1986). Amiga ROM Kernel Reference Manual. Exec.{{cite book}}: CS1 maint: location missing publisher (link)
  2. ^ Holloway, Tim (January 1991). "The Object-Oriented Amiga Exec: The design of the Amiga operating-system kernel follows the rules of object-oriented programming". Byte. No. January 1991. McGraw-Hill. pp. 329–332, 234. ISSN 0360-5280.
  3. ^ "Carl Sassenrath". Retrieved 2022-05-23.