Introducción al Sistemas Operativo z/OS Introducción a los Data Sets USING DATA SETS José Luis Calva Martínez Email:
[email protected] [email protected] INTRODUCTION In working with the z/OS operating system, you must understand data sets, the files that contain programs and data. The characteristics of traditional z/OS data sets differ considerably from the file systems used in UNIX and PC systems. To make matters even more interesting, you can also create UNIX file systems on z/OS, with the common characteristics of UNIX systems. A data set is a collection of logically related data; it can be a source program, a library of programs, or a file of data records used by a processing program. DtDataset recordsarethe bibasicunit of ifinforma tion used bby a processing program. José Luis Calva 1 Introducción al Sistemas Operativo z/OS Introducción a los Data Sets WHAT IS A DATA SET? Nearly all work in the system involves data input or data output. In a mainframe system, the channel subsystem manages the use of I/O devices, such as disks, tapes, and printers, while z/OS associates the data for a given task with a device. z/OS manages data by means of data sets. The term data set refers to a file that contains one or more records. Any named group of records is called a data set. Data sets can hold information such as medical records or insurance records, to be used by a program running on the system. Data sets are also used to store information needed by applications or the operating system itself, such as source programs, macro libraries, or system variables or parameters.