System files

The (standard) file names SYSDTA, SYSSTMT, SYSCMD, SYSIPT, SYSLST, SYSLST01, SYSLST02, ..., SYSLST99, SYSOPT and SYSOUT designate (system) files used by the operating system for data and command input to the operating system and for data output by the operating system. These files are created in each case by the task and initially designate (primary) specified input or output areas.
Users may cancel the primary assignment and assign their own cataloged files or complex S variables (when the SDF-P software product is used) to the (standard) file names.

The following system files are available to a job for input:

SYSCMD	Commands given by users to control the execution of their jobs are expected from SYSCMD. During the processing of the commands, i.e. in command mode (system mode), SYSCMD is active.
SYSDTA	The system file SYSDTA is used for the input of input data, i.e. data, parameters and statements, which a program reads in without the SDF interface (see the CMDRST or RDATA macro in the “Executive Macros” manual [22]). SYSDTA is active the moment a program begins execution, i.e. in program mode.
SYSIPT	This system file is only still available for reasons of compatibility and is consequently no longer described.
SYSSTMT	This system file is used for the input of statements to programs. The statements must be defined in a syntax file (see the “SDF-A” manual [33]).  The allocation made for the system file SYSDTA also applies for system file SYSSTMT. The continuation lines, continuation characters and comments used when entering SYSSTMT statements must comply with the rules for SYSCMD command entry.
The following system files are available to a job for output:
SYSOUT	The system directs logging messages and error messages arising during the currently executing job to SYSOUT. Utility routines and compilers also use SYSOUT in this way.  File name on primary allocation: S.OUT.tsn.yyyy-mm-dd.hhmmss.nnnn  If the system parameter SSMMILOG=Y is set during allocation to a PLAM library member then the output records are also written to the file S.OUT.lib.elem.tsn.nnnn.
SYSLST	In general larger data sets, such as memory dumps and listings generated by utility routines and compilers, are written to the system file SYSLST. In addition, SYSLST may contain records from the SYSOUT system file, if desired (specify LOGGING in the SET-LOGON-PARAMETERS or MODIFY-JOB-OPTIONS command).  File name on primary allocation: S.LST.tsn.yyyy-mm-dd.hhmmss.nnnn  If the system parameter SSMMILOG=Y is set during allocation to a PLAM library member then the output records are also written to the file S.LST.lib.elem.tsn.nnnn.
SYSLST01, SYSLST02, ..., SYSLST99
	Unlike the system file SYSLST, these system files do not have their own EAM area for storing output data. They are used for buffering and are operative only when cataloged files are assigned to them.
SYSOPT	This system file is only still available for reasons of compatibility and is consequently no longer described.

Meaning of the file name parts:

tsn	TSN of the task (4 characters)
yyyy-mm-dd	File creation date, where mm=month, dd=day of the month, yyyy=4-digit year specification
hhmmss	File creation time, where hh=hours, mm=minutes and ss=seconds
nnnn	4-digit counter
lib	First 7 characters of the PLAM library
elem	First 7 characters of the element name

The system files for output are normally output when a job is ended (EXIT-JOB or LOGOFF command) if no cataloged file or a complex S variable has been assigned to them and output was not suppressed on job termination. Depending on the setting of the system parameter SSMOUT, the files are output to printer or sent by email. If they cannot be sent by email, they are output to printer. Before the job has been completed, the system file can be output to printer using the PRINT-DOCUMENT command or sent by email using the MAIL-FILE command. Using the COPY-SYSTEM-FILE command, the system file SYSLST can also be copied to a file if SYSLST has the primary assignment.

In the PRINT-DOCUMENT and DELETE-SYSTEM-FILE commands, the (standard) file names SYSOUT and SYSLST may also be specified when cataloged files or complex S variables have been assigned to them. SYSLST and SYSOUT are rejected in the MAIL-FILE command if an S variable is assigned to them. 

Accessing system files

With the help of system files, user programs can input and output data. The system file SYSCMD represents an exception; it is accessible only to the system via privileged macros. The following table lists the macros and statements required to access system files.

System file	Macros that access system files	Language statements referring to system files:
	Assembler	COBOL	FORTRAN	PL/I	RPG3
SYSCMD	privileged	-	-	-	-
SYSDTA	RDATA	ACCEPT dataname FROM TERMINAL	READ (1,... READ (5,... READ (97,...	GET without FILE option	(DEVICE=) READER, no explicit statement
SYSSTMT	CMDRST 1) RDSTMT	1)	1)	-	-
SYSIPT 2)	-	-	-	-	-
SYSOUT	WROUT	DISPLAY dataname UPON TERMINAL	WRITE (2,...	DISPLAY dataname (without REPLY)	DSPLY
SYSLST	WRLST	DISPLAY dataname; DISPLAY dataname UPON SYSLST	WRITE (6,... WRITE (99,...	PUT without FILE option	(DEVICE=) PRINTER, no explicit statement
SYSOPT 2)	-	-	-	-	-

Table 5: Accessing system files

1)	There exists a High-Level Languages program interface for the programming languages C, COBOL and FORTRAN. The functions of the most important SDF macros (such as RDSTMT, CORSTMT and TRSTMT) are supported in function calls (see the “SDF-A” manual [33]).
2)	The system files SYSIPT and SYSOPT are only still available for reasons of compatibility.

Primary assignment and redirection of system files

In general, a specific assignment for the system files is preset. With the help of commands, this primary assignment can be changed; the following table provides an overview of this. Examples may be found in the descriptions of the commands involved.

System file	Primary assignment	Further assignments	Commands for changing the assignment
SYSCMD	in dialog: terminal in batch: spooling file (S.IN.), spooled in via magnetic tape device or ENTER file.	cataloged disk file (SAM/ISAM), library member or complex S variable	CALL-PROCEDURE: assignment to a cataloged file, a library member or a complex S variable End of procedure: assignment in effect when the last procedure was exited.
SYSDTA	same as SYSCMD primary assignment	cataloged file (SAM/ISAM), library member, complex S variable	ASSIGN-SYSDTA: assignment to a cataloged file, to a library member, to a complex S variable, to SYSCMD or back to the primary assignment. End of procedure: assignment in effect when the last procedure was exited.
SYSSTMT	same as SYSDTA primary assignment	same as SYSDTA	same as SYSDTA
SYSIPT	This system file is still provided for reasons of compatibility.	-	-
SYSOUT	in dialog: terminal in batch: temporary spoolout file (S.OUT.) which at the end of the job is printed out or sent by email and then deleted	cataloged file (SAM/ISAM), library member or complex S variable; no automatic printout or transfer by email	ASSIGN-SYSOUT: assignment to a cataloged file, to a library member, to a complex S variable, to SYSCMD or back to the primary assignment. End of procedure: assignment in effect when the last procedure was exited.
SYSLST	temporary spoolout file (S.LST.) which at the end of the job is printed out and then deleted (created only when needed)	cataloged file (SAM), library member or complex S variable; no automatic printout or transfer by email	ASSIGN-SYSLST: assignment to a cataloged file, to a library member, to a complex S variable, to SYSCMD or back to the primary assignment. End of procedure: assignment in effect when the last procedure was exited.
SYSLST01 . . . SYSLST99	current assignment of SYSLST	same as SYSLST; also possible between each other	same as SYSLST
SYSOPT	This system file is still provided for reasons of compatibility.	-	-

Table 6: Primary assignment and redirection of system files

Termination of the procedure and the resultant change in assignment can be explicitly effected by means of an EXIT-PROCEDURE, CANCEL-PROCEDURE or END-PROCEDURE command (only non-S procedures). A procedure is implicitly terminated on reaching end of file (EOF condition).