IBM 5280 Distributed Data System - Index of

Pointers to Global System TablesEach global system table pointer contains the address of a global system table.System tables contain the addresses of prompts, formats, tables, and other dataareas. System tables are used within each partition to contain the addresses of thedata areas within that partition. The global system tables contain addresses ofglobal data areas that are stored within the common area rather than within apartition. Data areas stored within a partition can be used only by that partition;however, global data areas can be used by any partition. Global data areas includea printer configuration table, screen formats, prompts for keyboard/display I/O,edit formats for diskette, printer, or communications I/O, data tables for tableoperations, and self-check data for self-check operations.Common Functions and Help TextFollowing the system control block is an area of variable length that containscommon function routines. These routines can be called from any partition; returnis made to the calling partition.The routines stored in the common functions area depend upon the individualsystem. A table of help text messages may be included in the common area. Thesemessages can be called from the keyboard in response to the Help key.Configuration TableA configuration table is included in the common area if one or more printers areattached to the system. The address of the configuration table is stored in thesystem control block.The configuration table has one entry for each printer. Each entry has such informationas the device subaddress and the number of entries the printer has in the softerror count table.Error Recording TablesTwo error tables are stored in the common area as global tables 0 and 1: (1) thesystem hardware error log, and (2) the soft error count table. The system error logis of variable length and is used by the microprocessors to record system hardwarerelatederrors. Each table entry has information to identify the device, lOB andprogram associated with the error. The soft error count table is used by the printermicroprocessor to record the number of soft printer errors that occur during programexecutions. These error tables provide a history of system hardware-relatederrors and I/O errors that can be written to a diskette with a special error logdump program. See the Data Areas and Diagnostics Aids Handbook for informationabout communications error tables.8