6.1 PROCESS MANAGEMENT

Digital UNIX provides a rich environment to users due to its multiprocessing and multi-user nature. The ability for multiple users to each run multiple jobs simultaneously is a blessing for end users. Of course, this ability is not limited to Digital 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 DEC's OpenVMS, and Microsoft's Windows NT. UNIX, however, and Digital 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 multi-user database applications, such as those based on Oracle, Informix, and Sybase.

A Digital 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 log-ins 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 dozen processes on a small, lightly used 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 I will cover the various attributes of a process, how these attributes interrelate, and which attributes can actually be adjusted to change the behavior of the process. In addition,...