9.1 Process Management

Tru64 UNIX provides a rich computing environment due to its multiprocessing and multiuser nature. The ability for multiple users to run multiple jobs simultaneously provides great flexibility to end users. Of course, this ability is not limited to Tru64 UNIX, nor even just to UNIX itself, but exists in a variety of computing environments, such as large mainframe environments, vendor proprietary systems such as Compaq's OpenVMS, and Microsoft's Windows 2000. UNIX, however, and Tru64 UNIX in particular, has gained a reputation since the early 1970s as the operating system of choice for supporting software development efforts, especially large team projects, and multiuser database applications, such as those based on Oracle, Informix, or Sybase.

A Tru64 UNIX system administrator comes to this environment needing the skills to understand and manage this multiprocessing capability. In UNIX, a single job, whether it has a system function, such as authenticating user logins or receiving and handling print requests, or is a user activity, such as compiling a C++ program or querying a database, is called a process. Managing these processes, which can be as few as a couple of dozen processes on an individual workstation, or many thousands of processes on a large database or Web server, is an important part of a system administrator's responsibility.

In this chapter, we discuss the various attributes of a process, how these attributes interrelate, and which attributes can be adjusted to change the behavior of a process. In addition, the parent/child process relationship...