The text read off it
[04.01.03]
and are responsible for maintaining it. In addition, changes in configuration, such as removal of a tape transport for maintenance can be reflected in the table by means of Basic Monitor control cards.
Besides the problem of general unit availability, programs operating within an automatic system are forced to use certain units to carry out specific functions. For example, the units to be used for Library tape, the input (job) tape, and the output (list) tape, cannot be chosen arbitrarily by a processor without doing violence to the notion of continuous operation. In order to provide a uniform way to reference this class of units, they have been assigned symbolic names indicative of their function. The particular unit currently assigned to a given function is found in the Unit Function table of the Nucleus. This table, together with the Unit Availability table, provides complete information on the current status of the I/O units available within the system.
The symbolic function names are alwyas used on Basic Monitor control cards, in order to effect changes in status for specific unit assignment for this class of units. The functional units of the current system are:
| Symbolic Name | Function |
|---|---|
| SYSLB1 | System |
| SYSLB2 | Library |
| SYSLB3 | and |
| SYSLB4 | Alternates |
| SYSCRD | System Card Reader |
| SYSPRT | System Printer |
| SYSPCH | System Punch |
| SYSIN1 | System Input |
| SYSIN2 | and Alternate |
| SYSOU1 | System Output |
| SYSOU2 | and Alternate |
| SYSPP1 | System Peripheral Punch |
| SYSPP2 | and Alternate |
| SYSCK1 | System Checkpoint Tape |
| SYSCK2 | and Alternate |
| SYSUT1 | System |
| SYSUT2 | Utility |
| SYSUT3 | Tapes |
| SYSUT4 |
The participating processors of the system do not necessarily use all of these units; nor do they use the Utility tapes for the same functions. In order to take full advantage of the tape handling facilities of the Basic Monitor, the operator should take the time to learn the unit requirements and usages for the various processors. The table of Section 06.02 provides such information of the CT Compiler, CT Loader, CT Maintenance, and Subroutine Files Updater.