Guide to Multitasking Operating Systems:Index

Guide to Multitasking Operating Systems
Introduction Fundamentals of Hardware Organization Fundamentals of Operating Systems Overview of the OS/2 Operating System Reference Material Troubleshooting Concepts Index

Machine language

The instructions which are recognized and executed by, the CPU of a computer. A machine language program is simply long sequence of 0's and 1's. The CPU will typically take a 32-bit string of 0's and 1's as an instruction. Since it is extremely difficult to write machine language programs directly, assemblers are used, in which the programmer uses mnemonics to symbolize the machine language instructions.

Typical Assembler Mnemonic:

MOV EAX,EBX     ;Move contents of EBX into EAX
Corresponding machine language instruction:
(wild guess...  get intruction formats and manually
  assemble the above instruction.)
  ...0110 1100 0101 0011...

Queue

A queue is like a waiting line at a bank with one teller, in which the first people that come into the line are the first people to be serviced by the teller, hence the First In First Out(FIFO) term.

Time-Slice

A time-slice The operating system keeps track of the value of the time-slice, and how much time each job has used up on its current time-slice.

Context-switching

Context-switching refers to the mechanism used by the operating system to stop running one job and to start running another. Among other things, the operating system must save the state of the CPU of the current job, i.e. contents of registers, stack and load the state of the CPU for the job that will take control of the CPU.

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