1. Operating system:  after being loaded into the computer by a boot program, it manages all of the other application programs in a computer.  

2.  data bus: transfers data between a computer's memory and its CPU

3.  instruction register:  the part of a CPU's control unit that holds the instruction currently being executed or decoded.

4.  accumulator: a memory location used to store the intermediate results of arithmetic and logical operations.

5. program counter: keeps track of the memory address of the next instruction to be executed in a program.  

6. control unit:  subcomponent of CPU that manages computer operations

7.  Memory management systems 

   1. single allocation is the simplest memory management technique. All the computer's memory, usually with the exception of a small portion reserved for the operating system, is available to a single application.

   2. Partitioned allocation divides primary memory into multiple memory partitions, usually contiguous areas of memory. Each partition might contain all the information for a specific job or task. Memory management consists of allocating a partition to a job when it starts and unallocating it when the job ends.

   3. Paged allocation divides the computer's primary memory into fixed-size units called page frames, and the program's virtual address space into pages of the same size. The hardware memory management unit maps pages to frames. The physical memory can be allocated on a page basis while the address space appears contiguous.

8. fetch-decode-execute cycle:

   1. Fetching an instruction from memory - supplying the address and receiving the instruction from memory.

   2. Decoding the instruction - interpreting the instruction and then reading and retrieving the required data from their addresses.

   3. Executing the instruction - the CPU carries out the required action  

9.  von Neumann architecture: consists of main memory, a central-processing unit (CPU) or processor or core, and an interconnection between the memory and the CPU 

polling: periodic checking of devices, by a central device to sample their status.