Setting aside space for a file. Mainframes make you set aside space for things stored on disk so that less disk space is wasted.
For more info on how to allocate a dataset click here
Batch Processing
Generally, an application that processes data with little to no user interaction. This is good for processing large databases where the process must go through each and every record. EXAMPLE: payroll, credit card payments (For more details click here)

Internal component of the z/OS operating system that points to where a data set is on DASD.

Cataloged Procedure
Prewritten JCL code. They include the IGYWC command and its varients.

A grouping of similar data sets. Several physical data sets come together and form a logical data set together.

CICS (Customer Information Control System) makes it possible for the system to run interactive programs written in COBOL, PL/I, assembler language, C, C++, or Java. (For more details click here)

Hardware in a mainframe that acts as a storage device. It comes as magnetic tape or optical drives.(For more details click here)

(Data Definition) It is used in a JCL to allocate the data sets needed to run a program.
For more info on how to fill in your Data Definitions click here

Data Set
A data set is comparable to a file. It is a collection of like data items stored on a mainframe. As an example, a cobol program is a data set. They must be allocated before they can be used. See Allocation. (See Data Set Tutorial)

DB2 (Database 2) is a database management system. It manages relational databases that can be accessed using SQL (Structured Query Language). (For more details click here)

Data Set List: A wonderful tool available to you through your ISPF that allows you to see a list of all the datasets you've ever allocated.
For more info on how to get to your DSLIST click here

(Extended Binary Coded Decimal Interchange Character) Likened to ASCII, this is the code used to store characters in the database z/OS operating system. It was developed before ASCII. This site gives you a comparison between ASCII and EBCDIC.

(Entry-Sequenced Data Set) Sequential data set where data is stored in the order in which it is entered. Each data item is located by its address which is static.

A simple poem. The only rule the writer must follow is that there must be five syllables in the first line, seven syllables in the second, and five in the third. Here are some examples.

(IntegrateD Catalog Access Method) Can perform a multitude of operations on a data set. Such activities include defining, loading, and deleting data sets. (For more details click here)

An IBM designed Hierarchical Database. (For more details click here)

ISPF (Interactive System Productivity Facility) provides a menu-driven, full-screen interface to most of TSO’s facilities. A part of ISPF called PDF is used to develop source programs and the JCL to compile and run them. For usage, see this page.

(Job Control Language) A set of instructions that communicates with the operating system to tell a mainframe what to do. These instructions can compile programs, but they can also accomplish other tasks. It names the job, and, depending on the what is in it, it can pull in other files that a job may need. (For an example of JCL code see here)

The Job Entry Subsystem (JES) keeps track of jobs and their output as they’re processed by the system. There are two versions of JES: JES2 and JES3.

(Key-Sequenced Data Set) Also known as "indexed data set," this format organizes data with indexes pointing to the data items. This leaves no holes as indexes can be reused to point to new data items as a database is updated.

Method of Access
Pulling data from a file can be done one of three ways:
  • Sequential - Data pulled in order from first to last
  • Random - Specific data pulled using a key
  • Dynamic - A combination of sequential access and random access'
(For more details click here)

Online Processing
Application involving heavy user interaction. This is good for processes that need accurate up-to-date information per update.

(Partitioned Data Set) You can look at it like file folders. They can hold many "files" called members. A PDS is named the following way HLQ.UDQ.LLQ(member).
  • HLQ (Hight Level Qualifier) - In our case, it is the username under which we are logged in. It functions as a root directory for all of our PDSs.
  • UDQ (User Determined Qualifier) - A user can determine this qualifier with whatever text they want. It generally describes what is stored within according to the user's preference.
  • LLQ (Low Level Qualifier) - It is a descriptive name that tells what type of files are stored within. Such ending are COBOL, JCL, DATA, TEXT, and LOAD.
  • Member - It is like the end file in a PDS. Many members can be stored in one PDS.
Each qualifier is 1-8 characters long, and the qualifiers are separated by periods.
(For more details click here)

RACF (Resource Access Control Facility) ensures that a user has the correct authority to access system resources and facilities.

(Relative Byte Address) Locates a part of a data set by using the starting point and the data item's displacement from that point.

(Relative-Record Data Set) Sometimes referred to just as a "relative data set," data is stored in fixed blocks of memory ordered by RRNs (Relative Record Numbers). Holes are left if none of the data fits that block of memory--for example if there is no customer with account number 00020, the memory space for 00020 is still allocated but left empty.

(System Display and Search Facility) This allows you to view jobs and their statuses. It includes an input queue, ouput queue, and held ouput queue. For usage, see this page.

Sequential Data Set
A data set that is written as a collection data stored in sequence from beginning to end. A PDS is a collection of these, that is to say, members are sequential data sets.

Cobol's equivalent of a function or subroutine. It is software that performs a particular operation. Other programs can call this program and have this service performed.

TSO/E (Time Sharing Option/Extended), often referred to just as TSO, is a subsystem that lets terminal users invoke system facilities interactively. (For more details click here)

(Virtual Storage Access Method) Advanced method of storing data. Similar to the idea of a buffer.

VTAM (Virtual Telecommunications Access Method) provides centralized control over all of the terminal devices attached to the System

Comes from the zSeries mainframe operating systems developed by IBM. Learn more on IBM's website.