Class 2 system parameters (in short: system parameters) can be preset via the startup parameter service after loading of and REP processing for the class 2 EXEC. Systems support is therefore able to react flexibly to changing specifications and objectives during system initialization.
The following restrictions must be observed:
system parameters may not be deleted or added
modification of particular attributes of the options (e.g. length of the permitted values) is not possible.
The keyword for modifying system parameters is SYSOPT-CLASS2.
The maximum number of permissible parameter records is 128.
Format of the parameter record for presetting system parameters
<sysopt> = <value>
sysopt
Denotes the name, not exceeding 8 characters, of a system parameter whose value is to be changed.
value
Denotes the value within the valid range for the specified system parameter. If a system option is assigned an invalid value, the SYSOPT statement is rejected. If more than one valid value is assigned to a system option, the last valid entry will be used.
A statement is valid if the type and the assigned value as well as the length are in keeping with the associated system option.
A brief description of all system parameters with value ranges can be found in the description of the SHOW-SYSTEM-PARAMETERS command in the “Commands” manual [27].
The specific interpretation rules are set forth below:
Type C system parameters (character strings)
The assigned value is interpreted as a character string. If the string is to contain blanks, the value must be prefixed with C and enclosed in apostrophes; in such cases, however, the value itself cannot contain any apostrophes. The string is entered left-justified and padded with blanks if necessary. If the specified string is longer than the maximum length of the system parameter, the SYSOPT statement is rejected.
Type A system parameters (arithmetic values)
The assigned value is interpreted as a positive decimal value. In cases where a minimum and/or maximum is defined for the specified system parameter, the value is checked accordingly. Otherwise, a minimum value of 0 is assumed and the maximum is calculated from the generated length (see length table).
Type X system parameters (hexadecimal values)
The assigned value is interpreted as a hexadecimal value and may therefore contain only hexadecimal digits (prefixed with X and enclosed in apostrophes). A minimum/maximum check is carried out as for type A on the basis of the generated length.
For type A the generated length may be 1, 2 or 4 bytes, for type X 1, 2, 4 or 8 bytes. If no maximum is defined, the following maximum value is accepted:
Length table
Type | Length = 1 bytes | Length = 2 bytes | Length = 4 bytes | Length = 8 bytes |
A | 255 | 65535 | 2147483647 | - |
H | FF | FFFF | FFFFFFFF | FFFFFFFFFFFFFFFF |
Extract from the parameter file
/BS2000 PARAMS : /BEGIN SYSOPT-CLASS2 BMTNUM=32 1. ENCRYPT=Y 2. EAMSPVS=X'01' 3.. TEMPFILE=C'#' 4. /EOF : /END-PARAMS
The number of input/output buffers for catalog management is set at 32.
Type of system parameter: A.It is declared that the system is to operate with encrypted passwords during the next session.
Type of system parameter: C.This statement controls how the SYSEAM file is handled on a shared pubset.
Type of system parameter: X.“#”is declared as a special character which must be prefixed to the names of temporary files and job variables throughout the next session.
Type of system parameter: C.
Dynamically modifiable system parameters
The following system parameters can be modified during operation by the user ID TSOS by means of the MODIFY-SYSTEM-PARAMETERS command:
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Nonprivileged system parameters
The following system parameters and their current values are also displayed for non privileged users by means of the SHOW-SYSTEM-PARAMETERS command:
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