Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Southeastern University 501 I Street SW Washington, DC 20024 Tel: (202) 488-8162 Fax: (202) 488-8093 Midterm Exam: Feb 9, 2002 Course: COSC 513 Operating Systems Instructor: Prof. M. Anvari Student Name: ___________________________ Student ID: ______________________ 1. Enter the names for layers 1,3, and 4 of computer system, as programmers and users view them. 4 3 1 2. How User-visible registers, and Control and status registers are used? User-visible registers – Enable programmer to minimize main-memory references by optimizing register use – May be referenced by machine language – Available to all programs - application programs and system programs Control and status registers – Used by processor to control operating of the processor – Used by operating-system routines to control the execution of programs Page 1 of 4 COSC513-Midterm Exam February 9, 2002 Prof. M Anvari 3. What types of information are kept in User-visible registers, and Control and status registers? Types of registers in User-visible registers: –Data –Address Index Segment pointer Stack pointer Types of registers in Control and status registers Program Counter (PC) –Contains the address of an instruction to be fetched Instruction Register (IR) –Contains the instruction most recently fetched Program Status Word (PSW) –Condition codes –Interrupt enable/disable –Supervisor/user mode 4. What is Interrupt and why do the Operating Systems provide interrupt-handling functions? Interrupts are provided as a way to improve processing efficiency. Handlers are responsible for managing the Interrupts. A program that determines nature of the interrupt and performs whatever actions are needed Control is transferred to this program Generally part of the operating system 5. In few words define Multiprogramming, Multiprocessing, Multithreading and Multitasking. Multiprogramming = Multitasking. Multiprocessing = Parallel Processing Multithreading = Ability to support multiple threads of execution within a single process and Not single thread of execution per process. 6. What is Cache Memory? Small cache of expensive but very fast memory interacting with slower but much larger memor Invisible to OS and user programs but interact with other memory management hardware Processor first checks if word referenced to is in cache If not found in cache, a block of memory containing the word is moved to the cache Page 2 of 4 COSC513-Midterm Exam February 9, 2002 Prof. M Anvari 7. What are the technological achievements of current modern operating systems? Processes Memory Management Information protection and security Scheduling and resource management System structure 8. What are the characteristics of current modern operation systems? Microkernel architecture Multithreading – Process is divided into threads that can run simultaneously – Process is a collection of one or more threads Symmetric multiprocessing Distributed operating systems Object-oriented design 9. How does the Operating System get executed? Non-process Kernel –execute kernel outside of any process –operating system code is executed as a separate entity that operates in privileged mode Execution Within User Processes –operating system software within context of a user process –process executes in privileged mode when executing operating system code Process-Based Operating System –major kernel functions are separate processes –Useful in multi-processor or multi-computer environment 10. What are the reasons for process terminations? Normal completion Time limit exceeded Memory unavailable Bounds violation Protection error –example write to read-only file Arithmetic error Time overrun –process waited longer than a specified maximum for an event I/O failure Invalid instruction –happens when try to execute data Privileged instruction Data misuse Operating system intervention –such as when deadlock occurs Parent terminates so child processes terminate Parent request Page 3 of 4 COSC513-Midterm Exam February 9, 2002 Prof. M Anvari 11. What are the categories of computers with parallel processing capabilities? 12. Describe the functions of User-level thread, Kernel-level thread, and Light-weight process. Which of the modern OS uses the LWP concept? Page 4 of 4 COSC513-Midterm Exam February 9, 2002 Prof. M Anvari