CP/M

CP/M, sold by Digital Research, Inc. of Pacific Grove, California, is very different from other software. For one thing it isn't written for any particular system. There are versions currently available for most of the popular small computers.

CP/M is also different in that it carries a substantial cost. It sells for $100 direct from Digital Research, and a version for the TRS-80 is priced at $150 from FMG Corporation. Lifeboat Associates of New York offers versions for many computers. Their price is $145.

While large corporations are accustomed to spending hundreds or thousands of dollars on software, small computer users have come to expect quite a bit for software in the above $100 category. They get it in CP/M. It is a major piece of software that not only provides the user with an expanded, more powerful operating system, it also serves as the foundation for many other programs. Language processors for BASIC, FORTRAN, and COBOL as well as application programs like word processors, data bases, and payroll software have been written for CP/M. These programs use the general purpose software routines incorporated in CP/M to reduce the amount of work that must be done to get a program written, debugged, and on the market. Tailoring applications software to CP/M rather than a particular computer also expands the population of potential purchasers. To the user, having CP/M means being less dependent on the manufacturer of the computer for applications software since most programs written for CP/M can be run on any computer that has CP/M.

CP/M requires a disk system and a substantial amount of memory to be used most effectively. CP/M is thus not part of a typical small system for home use, but an increasing number of businesses are buying disk based systems and CP/M. Such a combination, while priced well above the cost of entry level systems, is very competitive with the minicomputer alternatives that do the same jobs in a business environment. The manuals for CP/M are several hundred pages long. CP/M is composed of several subcomponents that do a particular job:

• Console Command Processor
• Basic Disk Operating System
• Editor
• Peripheral Interface Program
• Dynamic Debugging Tool

Console Command Processor CCP is part of the real world interface for the system. It is what the user talks to, and it in turn directs some of the activities of other subcomponents. CCP also has built-in routines to han- dle input and output from peripherals like printers and a CRT.