gtpi1m5u | System Installation Support Reference |
The following glossary of selected terms gives a quick overview of terms
used throughout this chapter; it is not intended to be complete and
exhaustive. Rather than being listed alphabetically, the terms progress
from simple to more complex concepts.
- globals.
- A generic term referring to any or all of the entities in the area of main
storage called the global area or to copies of these entities on DASD.
- global record.
- A logical collection of data, treated as a single entity, that can reside
in the main storage global area and that also resides on DASD as
large (1055-byte) records (also called application
core-resident records). As that name implies, global records are
typically used by application programs that need convenient access to main
storage records. TPF macros provide a variety of efficient services for
retrieving, addressing, and filing these records. The records can have
various attributes such as keypointability, SSU uniqueness or commonality, and
I-stream uniqueness or commonality.
- global field.
- A subset of certain global records, ranging in size from 1 to 256 bytes in
length. Global fields are individually addressable using the GLOBZ
macro, and they can share many of the attributes of global records.
- global block.
- The global records loaded from DASD with an ID of GL. These records
contain the data that make up the global fields, and they are the first items
loaded into global areas 1 and 3.
- global directory.
- A series of 8-byte fields at the start
of global area 1 and global area 3 that point to the main storage address and
file address of global records. These pointers are defined,
respectively, by the GL0BA and GL0BY DSECTs.
- subsystem user (SSU) unique/common.
- In a system with the Multiple Database function (MDBF), global records and
fields
can be shared among subsystem users (SSUs) in a subsystem or can be unique for
each SSU. In other words, an ordinal number used by different SSUs
either points to the same common record or to different unique ones.
- I-stream unique/shared.
- Records in a
tightly coupled (TC) system can be declared unique or shared among
I-streams. This term applies only to global records (not global fields)
and only to main storage copies (not DASD copies).
- primary globals.
- Globals that reside below the 16MB boundary
and are therefore accessible to programs running in 24-bit addressing
mode.
- extended globals.
- Global records that reside in an area of storage defined above the 16MB
boundary. The extended global area greatly expands the amount of
storage available for globals and relieves constraints on the amount of
storage available for data that must be accessible to programs running in
24-bit addressing mode. For each primary global area there is a
corresponding extended area. A system can be generated with or without
extended globals.
- global attribute table (GAT).
- Each global directory slot has a corresponding global attribute table
entry that identifies the characteristics of the global for example, SSU
unique/common or I-stream unique/shared. System programs use a special
macro to address this table; application programs do not require access
to it.
- SSU table.
- A table generated during system restart
that contains, for each SSU in the system, the address, size, and protection
key of each associated primary and extended global area and GAT. The
SSU table is organized by I-stream within global area within SSU. (The
global area organization is SSU within I-stream within global area).
- global storage allocator (GOA).
- A #GLOBL fixed-file
record that contains the information needed by the Application Core Load
program (GOGO) to load all the other #GLOBL records to the global areas (see
data macro GO1GO). A GOA must be manually prepared for each SSU as
input to the System Test Compiler (STC) so that it becomes part of a pilot
tape. The first such record in a chain is called the prime
GOA.
- super GOA.
- #GLOBL fixed file records that are used by the
GOGO program as an index to find the GOA associated with each I-stream/SSU
combination. A super GOA must be manually prepared as input to system
test compiler (STC) so that it becomes part of a pilot tape.
- global synchronization.
- A process that permits changes made to global fields and records to be
communicated among 2 or more active I-streams in a loosely coupled (LC) or
tightly coupled (TC) system to maintain currency. Synchronization
involves offline data record generation, online restart processing, and
real-time application interface processing.
- system interprocessor global table (SIGT).
- In an LC or
TC system, a table that stores information necessary for controlling the
locking, unlocking, and synchronization of user-specified synchronizable
global records or fields.