Abstract For a digital computer operating under a multilevel periodically occurring priority routine wherein information is transferable from a first field to a second field of a data store only during the lowest priority level, there is disclosed a method for updating information stored in the first field. The method contemplates preventing indiscriminate access to the first field. Instead, when during any level but the top priority level access is required to the first field for updating, the work being performed is interrupted and the computer switched to the top priority level. In this level, the updating information is simultaneously stored in corresponding locations of the first and second fields. Thereafter, the computer is restored to perform the interrupted work.
In a digital computer having a data store, an instruction store and a central processing unit, said digital computer working in real time on different priority levels and wherein variable data is transferable from a first address of a first field of the data store to a second address of a second field of the data store during the lowest priority level, the method of updating data in the first address when the digital computer is operating at a priority level other than the highest priority level, said method comprising the steps of interrupting the operations being performed by the digital computer when the updating is called for, switching the digital computer to the highest priority level, transferring the updating data to both the first address of the first field and the second address of the second field, and thereafter restoring the digital computer to continue performing the interrupted operations.
Claim 2
Dependent Claim
150 words
In a digital computer having a data store, an instruction store and a central processing unit, said digital computer working in real time on different priority levels and wherein variable data is transferable from a first address of a first field of the data store to a second address of a second field of the data store during the lowest priority level, the method of updating data in the first address when the digital computer is operating at a priority level other than the highest priority level, said method comprising the steps of interrupting the operations being performed by the digital computer when the updating is called for, switching the digital computer to the highest priority level, transferring the updating data to both the first address of the first field and the second address of the second field, and thereafter restoring the digital computer to continue performing the interrupted operations.