System files: primary assignments, reassignments, record formats

Primary assignments

At the start of a task, the system files in BS2000 are assigned to particular input/output devices. This is known as the primary assignment of the files and is dependent on the type of job (interactive mode or batch mode). The various options are summarized in the following table:

System file	Primary assignment
	in interactive mode	in batch mode
SYSDTA	Terminal	Spoolin file or ENTER file
SYSIPT	No primary assignment	Spoolin file or ENTER file
SYSOUT	Terminal	Temporary spoolout file (EAM file) which is output on the printer at task end and then deleted
SYSLST SYSLSTnn	Temporary spoolout files (EAM files), which are output on the printer at task end and then deleted
SYSOPT	Temporary spoolout file (EAM file), which is output on floppy disk at task end and then deleted.

Table 12: Primary assignments of the system files

Reassignments

The assignment of the system files can be changed in the course of a task by using the ASSIGN-system-file command, i.e. they can be redirected to other devices, system files, or even cataloged files.

A detailed description of the command can be found in the “BS2000/OSD-BC Commands” manual [3].

System file	Reassigned to ...	using the command
SYSDTA	cataloged disk file (SAM or ISAM) or PLAM library	ASSIGN-SYSDTA filename ASSIGN-SYSDTA *LIBRARY(library, element)
	floppy disk	ASSIGN-SYSDTA *DISKETTE(...)
SYSIPT	cataloged disk file (SAM or ISAM)	ASSIGN-SYSIPT filename
SYSOUT	cataloged disk file (tape or disk)	ASSIGN-SYSOUT filename (in batch mode only)
SYSLST SYSLSTnn	cataloged disk file (SAM)	ASSIGN-SYSLST filename ASSIGN-SYSLST *SYSLST-NUMBER(...)
	dummy file (*DUMMY)	ASSIGN-SYSLST *DUMMY
SYSOPT	cataloged disk file (SAM)	ASSIGN-SYSOPT filename or ASSIGN-SYSOPT filename, OPEN-MODE = EXTEND
	dummy file (*DUMMY)	ASSIGN-SYSOPT *DUMMY

Table 13: Reassignments of system files

Record formats

The system files process fixed-length records (record format F) or variable-length records (record format V). The following table provides an overview of the record formats and record lengths permissible in each case.

System file	Record format	Record length
SYSDTA	V	When input via terminal or disk file: max. 32 Kbytes
	F	When input via card reader: max. 80 bytes
SYSIPT	F, V	Max. 80 bytes of data if SAM file. Max. 80 bytes: 72 bytes of data if ISAM file, bytes 73-80 contain ISAM key.
SYSOUT	V	In batch mode: max. 132 bytes (+ 1 line-feed character)
		In interactive mode: max. 32 Kbytes
SYSLST SYSLSTnn	V	Max. 133 bytes: 1 byte control information and 132 bytes data
SYSOPT	F	Max. 80 bytes: 72 bytes of data; bytes 73-80 contain the first 8 characters of the name from the PROGRAM-ID

Table 14: Record formats and record lengths for system files