list of letters
This site contains terms and definitions from many IBM software and hardware products as well as general computing terms.
16-bit code set
See double-byte character set.
See disk 16 pack.
A keyboard for non-programmable workstations that is associated mostly with IBM terminals that are attached to IBM controllers such as the 3174, 3274, and 5294. It has 104 keys in all versions except Katakana, which has 106 keys. A numeric key pad option adds another 18 keys to the keyboard. See also G keyboard.
See One Face To Development.
A method of transaction processing where transactions are committed on the primary server and then propagated to the secondary server afterward. If the primary server fails before it sends the transactions to the secondary server, the transactions will not be visible on the secondary server. See also 2-safe algorithm.
Virtual storage below the 16 MB address in a z/OS address space. Addresses below the 16 MB address are accessed by 24-bit addressing, and programs can use this storage when they run in AMODE 24 or higher.
24-bit storage addressing
The addressing structure of the original MVS operating system, which supports addressing up to 16 MB of real and virtual memory. The architecture has since been extended with 31- and 64-bit addressing. See also 31-bit storage addressing, 64-bit storage addressing.
24-bit virtual storage constraint relief (24-bit VSCR)
The movement of areas of code or control blocks to storage above the 16 MB line, or the reduction of code or control blocks below the 16 MB line. These actions increase the storage available for user programs and data that use 24-bit addressing.
See 24-bit virtual storage constraint relief.
2 B-channel transfer feature
See Integrated Services Digital Network two B-channel transfer.
See biconnected graph.
See Two-Party Key Distribution Protocol.
A method of transaction processing where transactions are not considered committed on the primary server until the transaction is confirmed committed on the secondary server. All updates to the data are applied to both copies synchronously. The disadvantage of a 2-safe system is that if the secondary server fails, the primary server stops accepting transactions. See also 1-safe algorithm.
Virtual storage above the 16 MB address but below the 2 GB address in a z/OS address space. Addresses above the 16 MB address but below the 2 GB address are accessed by 31-bit addressing, and programs can use this storage when they run in AMODE 31 or higher.
31-bit storage addressing
An addressing structure introduced with the MVS/XA operating system that supports addressing up to 2 GB of real and virtual memory, in addition to the prior support for 24-bit addressing. The architecture has since been extended with 64-bit addressing. See also 24-bit storage addressing, 64-bit storage addressing.
31-bit virtual storage constraint relief (31-bit VSCR)
The movement of areas of code or control blocks to storage above the 2 GB bar, or the reduction of code or control blocks below the 2 GB bar. These actions increase the storage available for user programs and data that use 24-bit or 31-bit addressing.
See 31-bit virtual storage constraint relief.
3270 attention field
A field on a display screen that contains a null, a space, or an ampersand in the first position. The field can be selected using the Cursor Select key, which causes data to be sent to the host system.
3270 display emulation
The function of i5/OS 3270 device emulation support that converts 3270 data streams intended for a 3278 display station into data streams that can be recognized by a display station attached to the system.
3270 printer emulation
The function of i5/OS 3270 device emulation support that converts 3270, DSC, and SCS data streams intended for a 328X printer into data streams that can be recognized by a printer attached to the system.
A function of WebSphere Voice Response that provides a software interface between DirectTalk and IBM System/370, System/390, or iSeries architecture business applications that interact with terminals supporting the 3270 data stream. See also custom server.
A mode of running the storage management subsystem (SMS) in which up to 32 names, representing systems, system groups, or both, are supported in the SMS configuration. When running in this mode, the system can share source control data sets (SCDSs), active control data sets (ACDSs), and communications data sets (COMMDSs) only with other systems running in 32-name mode. See also compatibility mode.
390 hexadecimal floating point format
See IBM 390 hexadecimal floating point format.
See Triple Data Encryption Algorithm.
The third generation of wireless technology. Multimedia 3G networks transmit wireless data up to 2 megabits per second, making possible the integration of voice, data and video. See also streaming.
See third-generation language.
3-state check box
A square box with associated text that represents a choice. Unlike a regular check box, which has only two states (selected and deselected), a 3-state check box has three states (selected, deselected, and unavailable). The unavailable state is displayed as a halftone and denotes that the 3-state check box cannot be selected.
Any display device that uses the 5250 data stream. See also Programming Development Manager.
- A Lucent Technologies switch.
- The ISDN protocol implemented on the 5ESS switch, providing 23 B-channels and a D-channel over a T1 trunk.
Virtual storage above the 2 GB address in a z/OS address space. Addresses above the 2 GB address are accessed by 64-bit addressing, and programs can use this storage when they run in AMODE 64.
64-bit storage addressing
An addressing structure introduced with the OS/390 Version 2 Release 10 for real memory, and enhanced in z/OS Version 1 Release 2 to add support for virtual memory. It supports addressing up to 16 EB of real and virtual memory, in addition to the prior 24- and 31-bit addressing modes that support 16 MB and 2 GB of addressable memory. See also 24-bit storage addressing, 31-bit storage addressing.
An algorithm for encoding data for transmission in which each 8-bit data byte is converted to a 10-bit transmission character. 8B/10B encoding supports continuous transmission with a balanced number of ones and zeros in the code stream and detects single bit transmission errors.
A single-byte character that consists of eight bits, which means that the code point is in the range 128 through 255. See also single-byte character.
See compatibility mode.
See disk eight pack.