Keyboard

Enhanced Definition

In the context of IBM mainframe systems, a keyboard is the primary input device used by users to interact with the z/OS operating system and its applications. It facilitates the entry of commands, data, and program code, predominantly through **3270 terminals** or their modern emulations.

Key Characteristics

- 3270 Keyboard Layout: Features a distinct layout with dedicated function keys (Program Function or PF keys), Program Attention (PA keys), Enter, Clear, Erase EOF, and other specific keys crucial for mainframe interaction.
- Block Mode Operation: Unlike character-mode terminals, 3270 keyboards operate in block mode, where input is buffered locally on the terminal and sent to the host only when an AID (Attention Identifier) key (e.g., Enter, PF keys, PA keys) is pressed.
- EBCDIC Character Set: While physical keyboards transmit scan codes, the logical input processed by the mainframe is typically encoded in EBCDIC (Extended Binary Coded Decimal Interchange Code).
- Terminal Emulation: Modern mainframe users primarily interact using 3270 terminal emulators (e.g., IBM Personal Communications, x3270) on PCs, which map standard PC keyboard keys to their 3270 equivalents.
- Non-Programmable Device: The physical keyboard itself is a "dumb" input device; all processing logic resides within the terminal controller or the terminal emulator software.

Use Cases

- TSO/ISPF Interaction: Entering TSO commands, navigating ISPF panels, editing JCL, COBOL programs, or other datasets using the ISPF editor.
- CICS Transaction Entry: Typing transaction codes and input data into CICS (Customer Information Control System) applications for online processing.
- IMS TM Interaction: Entering commands and data for transactions managed by IMS Transaction Manager (IMS TM).
- System Console Operations: System programmers and operators use keyboards to issue z/OS operator commands (e.g., DISPLAY, START, STOP) to monitor and control the system.
- Application Data Entry: For legacy green-screen applications, operators use keyboards for high-volume data entry into databases like DB2 or IMS DB.

Related Concepts

The keyboard is inextricably linked to the 3270 terminal architecture, serving as the user's interface to the terminal's display and controller. Its input is processed by interactive environments like TSO/ISPF, CICS, and IMS TM, which interpret the entered commands and data. The concept of AID keys is fundamental to how keyboard input is transmitted and processed in the 3270 block mode, distinguishing it from ASCII terminal interactions.

Best Practices:

Master 3270 Key Functions: Familiarize yourself with the specific functions of PF keys, PA keys, Clear, Erase EOF, and other unique 3270 keys for efficient navigation and command execution.
Customize PF Keys: Leverage the ability to customize PF keys in ISPF and other applications to quickly execute frequently used commands or navigate panels.
Utilize Emulator Shortcuts: Learn and use keyboard shortcuts provided by your 3270 terminal emulator for common tasks like copy/paste, screen capture, or session management.
Efficient Data Entry: For applications requiring high-volume data input, practice touch-typing and understand application-specific field navigation to maximize throughput.
Security Awareness: Be mindful of sensitive information entered via the keyboard, especially in shared environments, and ensure your terminal emulator and connection are secure.