Specifying Class Buffer Limits
Buffer limits for class requests are specified with the CL command. (The CL command supercedes the SL command.) If the upper class limit does not leave at least 1000 words of SAM remaining, the generator issues a warning. The command
CL,1000,2000
can be used to set the lower and upper limits for class requests. With this command, the class system will suspend a program when more than 2000 words of SAM are being used by buffers allocated for that class number. This suspension allows the buffers to be used by other programs. Class requests will restart when less than 1000 words of SAM are being used by the allocated buffers.
The default lower limit is 1/16 of SAM and the upper limit is 1/8 of SAM. To specify the default values, either enter CL without parameters or enter •CL,,,".
If you do not have class I/O in your system, you may enter:
CL,0,0
If you do have class I/O, specifying the CL command with zeros does not give the default values.
Note that CI uses class I/O, so do not specify a limit of zero if your system has CI.
Specifying Background Priority and Timeslice Quantum
Background program swapping priority is specified following SAM allocation. The default background priority limit is 30, but any number between 0 and 32767 can be used. (The highest program priority in RTEA is 1.) Refer to the System Design Manual for further information.
Next, the quantum timeslice value is specified. This value is specified in milliseconds in the range of 0 and 32767. Timeslicing begins at a particular priority limit specified in the quantum timeslice command string. The default timeslice quantum is 1000 milliseconds and the default timeslice priority is 50.
Specifying Shared Programs
Following the timeslicing specification, the number of shared programs is specified. The generator creates a table of five words for each shared program. The command
SP,2
allows space for up to two shared programs in the system. This allows up to two different shared programs in the system. Each different shared program requires an entry in the shared program table. The number of copies of each shared program is limited by the number of ID segments in the system.
If you do not have VC+, enter:
SP,0
74 Memory Allocation Phase