Questions and Answers of Computer Engineering

List two disadvantages of ULTs compared to KLTs.
Define jacketing.
Briefly define the various architectures named in Figure 4.8.
List the key design issues for an SMP operating system.
Give examples of services and functions found in a typical monolithic OS that may be external subsystems to a microkernel OS.
List and briefly explain seven potential advantages of a microkernel design compared to a monolithic design.
Explain the potential performance disadvantage of a microkernel OS
List three functions you would expect to find even in a minimal microkernel OS.
It was pointed out that two advantages of using multiple threads within a process are that (1) less work is involved in creating a new thread within an existing process than in creating a new
In the discussion of ULTs versus KLTs, it was pointed out that a disadvantage of ULTs is that when a ULT executes a system call, not only is that thread blocked, but also all of the threads within
In OS/2, what is commonly embodied in the concept of process in other operating systems is split into three separate types of entities: session, processes, and threads. A session is a collection of
Consider an environment in which there is a one-to-one mapping between user-level threads and kernel-level threads that allows one or more threads within a process to issue blocking system calls
If a process exits and there are still threads of that process running, will they continue to run? LEWI96-42
The OS/390 mainframe operating system is structured around the concepts of address space and task. Roughly speaking, a single address space corresponds to a single application and corresponds more or
A multiprocessor with eight processors has 20 attached tape drives. There is a large number of jobs submitted to the system that each require a maximum of four tape drives to complete execution.
List four design issues for which the concept of concurrency is relevant.
What are three contexts in which concurrency arise?
What is the basic requirement for the execution of concurrent processes?
List three degrees of awareness between processes and briefly define each.
What is the distinction between competing processes and cooperating processes?
List the three control problems associated with competing processes and briefly define each.
List the requirements for mutual exclusion.
What operations can be performed on a semaphore?
What is the difference between binary and general semaphores?
What is the difference between strong and weak semaphores?
What is a monitor?
What is the distinction between blocking and non-blocking with respect to messages?
What conditions are generally associated with the readers/writers problem?
Consider the following program: Const int n = 50; Int tally; Void total () { Int count; For (count = 1; count
Is busy waiting always less efficient (in terms of using processor time) than a blocking wait? Explain.
Consider the following program: Boolean blocked [2]; Int turn; Void P (int id) { While (true) { Blocked [id] = true; While (turn! = id) { While (blocked [1-id]) /* do nothing */; Turn =
Now consider a version of the bakery algorithm without the variable choosing. Then we have Int number[n]; While (true) { Number[i] = 1 + getmax (number [], n); For (int j = 0; j < n; j++)
Give examples of reusable and consumable resources.
What are the three conditions that must be present for deadlock to be possible?
What are the four conditions that create deadlock?
How can the hold-and-wait condition be prevented?
List two ways in which the no-preemption condition can be prevented.
How can the circular wait condition be prevented?
What is the difference among deadlock avoidance, detection, and prevention?
What requirement is memory management intended to satisfy?
Why is the capability to relocate processes desirable?
Why is it not possible to enforce memory protection at compile time?
What are some reasons to allow two or more processes to all have access to a particular region of memory?
In a fixed-partitioning scheme, what are the advantages of using unequal-size partitions?
What is the difference between internal and external fragmentation?
What are the distinctions among logical, relative, and physical addresses?
What is the difference between a page and a frame?
What is the difference between a page and a segment?
What is the difference between simple paging and virtual memory paging?
Explain thrashing.
Why is the principle of locality crucial to the use of virtual memory?
What elements are typically found in a page table entry? Briefly define each element.
What is the purpose of a translation look aside buffer?
Briefly define the alternative page fetch policies.
What is the difference between resident set management and page replacement policy?
What is the relationship between FIFO and clock page replacement algorithms?
What is accomplished by page buffering?
Why is it not possible to combine a global replacement policy and a fixed allocation policy?
What is the difference between a resident set and a working set?
What is the difference between demand cleaning and precleaning?
Differentiate between an abstract resource and a physical resource. Give two examples of each.
What abstractions do the IBM PC BIOS routines provide to the Intel 8088 abstract machine that are not available by using the hardware directly?
Suppose that you had a collection of “widgets;’ stored in a rectangular grid (like a table). You could reference the widget stored in the ith row, jth column by using the ordered pair of numbers,
In an object-oriented programming language like Java or C++, how can a program cause a value to be stored into a private variable inside of a different object? Another way to think about this is that
Identify which of the following are examples of space-multiplexed sharing, and which are time-multiplexed sharing. If there is a sense that it could be either strategy, explain.a. The land in a
Discuss some factors that must be considered in determining the maximum number of multiprogrammed processes for a particular system. You may assume a batch system with the same number of processes as
Suppose that a multiprogrammed system has a load of N processes with individual total execution times of t1, t2,., tN. How would it be possible that the execution time could be as small as maximum
Suppose that a multi programmed system has a load of N processes with individual total execution times of t1, t2 tN. How would it be possible thatT > t1 + t2 + … + tN?That is, what could cause
When is batch processing the preferred strategy for work to be done by the computer? When is timesharing the preferred strategy?
How might a timesharing processor scheduler’s policy differ from a policy used in a batch system?
What are some distinctions among Windows NT, Windows 2000, and Windows XP?
What are some distinctions between AT&T (System V) UNIX and BSD UNIX?
What is the relationship of POSIX.1 and Linux?
What is the purpose of the hardware abstraction layer in a Windows operating system?
How is a UNIX make file similar to a batch file? How is it different from the control file described in the chapter?
What is the contribution of timesharing technology to contemporary operating systems?
What is the contribution of embedded systems technology to contemporary operating systems?
Write a program to merge two sorted files into a single file using Linux/UNIX.
Write a program to merge two sorted files into a single file using any version of Windows.
Successive overrelaxation (SOR) is a method used to solve linear n × n systems of equations, Ax = b. Given the coefficient matrix A, the fight-side vector b, and an initial estimated solution
Write a C/C++ program, vt, that will enable a user to simultaneously execute two interactive sessions. The vt program should support the two sessions by “filtering” all keyboard input before
Write a UNIX program that creates a child process that prints a greeting, sleeps for 20 seconds, then exits. The parent process should print a greeting before creating the child, and another after
Write a Windows program that creates a child process that prints a greeting, sleeps for 20 seconds, then exits. The parent process should print a greeting before creating the child, and then
Suppose that a UNIX kernel supports threads. Would you expect the thread system call to take about the same amount of time to execute as fork ( )? Why or why not?
Provide a C code fragment to show how you could implement the WindowsCreateFile( LPCTSTR 1pFileName,DWORD dwDesiredAccess,DWORD 0,LPSECURITY ATTRIBUTES NULL,DWORD dwCreationDisposition,DWORD FILE
Describe how a shell script (or any other file containing a reference to a program) could “automatically” be executed once every hour in a UNIX system.
POSIX defines a standard thread package in the context of the C programming language. Several manufacturers provide a POSIX thread package as a user library along with their C programming facilities.
Consider the program as shown below. The C stdio library provides a similar set of file operations using the FILE data structure for a file description. Rewrite the simple file copy example in the
Write a shell script to interrogate the operating system to determine the number of processes considered by the short-term scheduler for processor allocation (processes currently “ready to run”)
Write a C/C++/UNIX procedure, getTime ( ), that returns the execution time of code segments by calling it before the code segment is executed and again after the code segment is executed; for
When the trap instruction was introduced, it was suggested that it might not be good for the user program to be able to reference the trap table index for a particular system function. Give some
Speculate about some factors that differentiate between the time to do a normal procedure call from an application program to one of its own procedures, compared to the time it takes to perform a
Assume the OS for a set of workstations provides a message-passing mechanism. Explain how one might implement a shared memory environment on top of the mechanism. Think of arguments explaining why
The original IBM PC and its clones employed the Intel 8088/8086 microprocessor. This machine did not incorporate a mode bit for supervisor and user modes. Hence, any application program (written in
The machine instructiona. br FIXED_DESTcauses the computer to execute its next instruction from memory location FIXED_DEST. What are the detailed steps of the ALU and/or control unit to execute this
The code below describes the fetch-execute algorithm for a sequential control unit. The discussion of the control unit informally describes how a machine can be made to run much faster by overlapping
Suppose a workstation has a clock rate of 25 MHz, which means that the machine is capable of performing 25 million basic operations per second. For example, a register test instruction might take
High-level programming languages can be thought of as abstract machines for machine language instruction sets. Given the C assignment statementa = b + c;do the following:a. Describe an implementation
Evaluate the following expressions that have binary operands. Check your work by converting the numbers to decimal and performing the same operations.a. 10101111 + 00101010b. 11101011 – 10101010c.
Convert each number into a hexadecimal (base 16) representation, then evaluate the expressions in hexadecimal.a. 10101111 + 00101010b. 11101011 – 10101010c. 10111011 x 00001011d. 01001000 / 00001100

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