os-习题1-answer.docVIP

FILL IN THE BLANKS.(10 * 1分) A program that is loaded into memory and is executing is commonly referred to as ________.(process) A software generated interrupts caused by an error or by specific request form user program that an operation system service be performed is called_________. (trap) There are two common models of communication. they are called ______、______(message-passing model and shared-memory model) A process, when it is not executing ,is placed in some waiting queues. there are two major classes of queues in the operating system :_____queue 、____queue(I/O request 、ready) In general, _______scheduling has a minimal average waiting time.(SJF) CHOICES(8 * 1分) which of the following instructions is not privileged( )B A.Clear memory B. Arithmetic operation C. Turn off interrupts D. Switch from user to monitor mode which of the following scheduler has the highest frequency( )B A. Long-term scheduler B. Short-term scheduler C. Medium-term scheduler In order to achieve minimal response time in foreground processes, you prefer to use ( ) scheduling.D A. FCFS B. Preemptive SJF C. Nonpreemptive SJF D.RR In which state of a process can be scheduled by dispatcher( )A A. Ready B. Running C. Waiting D. New 5、 Which of the following items is not a part of PCB( )D A. Process state B. Program counter C. CPU registers D.User data 6 which of the following model can cause the entire process block if a thread makes a blocking system call( ) C. A one to one model B many to many C many to one D none of them 7 which kind of OS have well-defined , fixed time constraints( )A A real –time B time –sharing C batch system