They write software to handle specific jobs, such as a program used in an inventory control system or one to guide a missile after it has been fired. They also may work alone to revise existing packaged software. Systems programmers, on the other hand, maintain the software that controls the operation of an entire computer system. These workers make changes in the sets of instructions that determine how the central processing unit of the system handles the various jobs it has been given and communicates with peripheral equipment, such as terminals, printers, and disk drives. Because of their knowledge of the entire computer system, systems programmers often help applications programmers determine the source of problems that may occur with their programs.
Many programmers develop packaged software.
Working Conditions Programmers work in offices in comfortable surroundings. They usually work about 40 hours a week, but their hours are not always from 9 to 5. Because programmers spend long periods of time in front of a computer monitor typing at a keyboard, they are susceptible to eyestrain and back discomfort and hand and wrist problems. Employment Computer programmers held about 555,000 jobs in 1992. Applications programmers work for all types of firms that use computer systems.