System Software：练习题

Which of the following is the primary purpose of an Operating System (OS)?

During the compilation process of a high-level language, the compiler first performs a stage where it removes comments and whitespace and converts the source code into a stream of tokens. What is the name of this stage?

A server with virtual memory enabled is experiencing a significant drop in performance. Monitoring shows that the hard disk activity is nearly constant, while the CPU utilization has fallen to a very low level. Which of the following best describes the cause of this situation?

A multi-tasking operating system is managing several processes. One specific management task involves the allocation of the CPU to a process in the Ready queue using a Round Robin algorithm. Which operating system management task is primarily responsible for this activity?

Consider the following Backus-Naur Form (BNF) definition for a simple mathematical expression:

<digit> ::= 0 | 1 | 2 | 3
<op> ::= + | -
<expr> ::= <digit> | <digit> <op> <expr>

Which of the following strings is NOT valid according to these rules?

State one primary purpose of an Operating System (OS) in a computer system.

Explain how the use of Dynamic Link Library (DLL) files allows an operating system to manage primary memory more efficiently when multiple applications that share common routines are executing simultaneously.

System Software

An Operating System (OS) is a fundamental component of any computer system.

(a) Explain two key purposes of an Operating System, providing an example for each.

(b) Describe how an Operating System manages processes, outlining the three main process states.

A multi-tasking operating system (OS) manages several processes simultaneously using various scheduling and memory management techniques.

(a) Describe the transition of a process from the Running state to the Blocked state, and subsequently from the Blocked state to the Ready state. Identify the specific types of events that would trigger each transition.

(b) During a context switch, the operating system must save the state of the current process so it can be resumed later. Identify two items of data, other than the process state, that would be stored in the Process Control Block (PCB) or equivalent structure to facilitate this.

(c) The operating system uses virtual memory to manage physical RAM efficiently.
(i) Distinguish between paging and segmentation by comparing how memory is divided and allocated in each method.
(ii) Explain the cause of disk thrashing and describe its impact on the CPU utilization of the computer system.