Batch Multiprogramming VS. Time Sharing Table 2.3 Batch Multiprogramming versus Time Sharing Batch Multi multiprogramming Time Sharing Principal objective Maximize processor use Minimize response time Source of directives to Job control language Commands entered at the operating system commands provided with the terminal 11
11 Batch Multiprogramming vs. Time Sharing
Early EXample: CTSS Compatible Time-Sharing System(CTSS Developed at mit as project mAc Time Slicing When control was passed to a user User program and data loaded Clock generates interrupts about every 0.2 sec At each interrupt os gained control and could assign processor to another user 12
12 Early Example: CTSS • Compatible Time-Sharing System (CTSS) – Developed at MIT as project MAC • Time Slicing: – When control was passed to a user – User program and data loaded – Clock generates interrupts about every 0.2 sec – At each interrupt OS gained control and could assign processor to another user
CTSS Operation 0 Monitor Monitor Monitor 5000 5000 5000 JOB 3 10000 JOB I JOB 2 20000 (OB 2) Free 5000 Free Free 32000 32000 200 Monitor Monitor Monitor 5000 5000 5000 JOB 4 JOB 1 15000 JOB 2 (JOB 1) 20000 20000 (JOB 2) (JOB 2) 25000 25000 25000 Free Free Free 32000 32000 32000 Eigure2-eissoperation
13 CTSS Operation
Roadmap The evolution of operating systems eOs Objectives and Functions Instruction Execution Interrupts The Memory Hierarchy Cache Memory 10 Communication Techniques
14 Roadmap – The Evolution of Operating Systems –OS Objectives and Functions – Instruction Execution – Interrupts – The Memory Hierarchy – Cache Memory – I/O Communication Techniques
Operating system A program that controls the execution of application programs An interface between applications and hardware Main objectives of an os Convenience Efficiency ability to evolve
15 Operating System • A program that controls the execution of application programs • An interface between applications and hardware • Main objectives of an OS: – Convenience – Efficiency – Ability to evolve