Summary

The framework in which a process carries on its activities is its processing environment. The processing environment consists of a number of components . A series of identification numbersprocess ID, parent process ID, and process group IDare used to reference the individual process, its parent, and the group with which the process is affiliated . In its environment a process has access to resources (i.e., files and devices). Access to these resources is determined by permissions that are initially set when the resource is generated. When accessing files, a process can obtain additional system information about the resource. All processes are constrained by system-imposed resource limits. A process can obtain limit information using the appropriate system call or library function. Processes may receive signals that in turn may require a specific action. The values passed via the command line to the process can be obtained. In addition, the process has access to, and may modify (in some settings), environment variables . Linux also supports a /proc directory that contains special files with information about the kernel, its data structures, and all active processes.