operating system course

Question Bank 20.1 Why Linux is considered an open-source system? 20.2 With a diagram explain the three main components of a Linux system. 20.3 What are the steps in successfully installing a Linux system? 20.4 Which are the popular Linux systems? 20.5 Which Linux is most often used as servers? 20.6 Why are Linux clusters popular?

Question Bank 19.1 List and describe five major functions of a system administrator. 19.2 What are typical start-up and closing down considerations? 19.3 What are the provisions a system administrator need to make for a new user? 19.4 In a multi-user system, how is the disk quota allocated? 19.5 How the disk partitions are created? 19.6 What is the role of .rc files? 19.7 Describe the use of .cshrc file 19.8 Describe the typical facilities that a mail system provides. 19.9 Describe five typical provisions to facilitate chat sessions over a network. 19.10 What are terminal settings? Describe the characteristics of vt100 terminal. 19.11 What is terminal emulation? How does it help? 19.12 Give an example of use of sty command. 19.13 What is the role of a print cap file? What is spooling? 19.14 How are the floppies handled in Linux environment? 19.15 What are the disk integrity checks? Give at least two checks to check out the integrity of a disk. 19.16 Create a mark display system. This h...

Question Bank 18.1 What is a GUI as opposed to an API? 18.2 What are X-servers and X-clients? 18.3 What is a “window manager”? List five distinct window manager functions. 18.4 How are the functions a window manager handled? 18.5 Describe the use of xterm. 18.6 Describe the role of a .xinitrc file. What is its role in at the start up and subsequently? 18.7 Suppose your terminal is connected to host iiitb1. Your application is required to run on iiitb2. But you have to display the results on the screen of iiitb3. How can you achieve this? 18.8 Describe some of the considerations that you may have if you were to customize an API for the following applications a. A data-base query interface b. A web application interface

Question Bank 17.1 Why is a versioning tool needed? 17.2 Why does SCCS use a special format? 17.3 What is the admin command used for? 17.4 What are the state transitions possible in SCCS? 17.5 Describe the use of various options available in SCCS? 17.6 Write a program in c which may have variability of options to choose by selecting appropriate configuration. Draw the corresponding versioning tree. 17.7 Repeat the problem above in Windows environment with the configurability determined by the dll files. 17.8 Corresponding to the SCCS in UNIX what is the facility available in Linux and Windows. 17.9 Use the SCCS tool to generate different versions of a program and print all the different versions.

Question Bank 16.1 What is the primary use of tar command? 16.2 Describe the options available and their use in tar command. 16.3 What is the strategy you would follow to transfer your files over the network when you change your place of work? (Assume your new location has given you a login account.) 16.4 Write a shell script that will replicate the behavior of tar program. 16.5 What is the extent of compression achieved say for text files under UNIX? Compare the efficacy of the compression when you zip with when you use compress command for text files. 16.6 Why compression of image files can be organized differently then say text files? 16.7 What is a lossy compression? Is the compression of a text file using compress command in UNIX lossy? 16.8 How does one attempt profiling of a program? Suppose a program is developed by having a main program which is used as a switching program to always call a function. Suggest a strategy that will find out which function engages the processor mos...

Question Bank 15.1 What is the basic facility make provide under UNIX? 15.2 How does make help to enhance personal productivity? 15.3 How does make help to enhance project productivity? 15.4 What is the basic file structure of a make file? 15.5 What are the different options available under make? What does -i option indicate under make? Show its use by an example. 15.6 What is the basic inferencing mechanism under make. 15.7 What are interpretations of the macros $@, and $< in make. 15.8 What are some of the standard conventions used by experienced make file users? 15.9 What is a Mastermakefile and what is its use? 15.10 Write a make file for the following • Makefile • a.c • b.c • c.c • abc.h • prog1.c • prog2.c a.c is defined as #include <stdio.h> void a() { printf("function a\n"); } b.c is defined as #include <stdio.h> void b() { printf("function b\n"); } c.c is defined as #include <stdio.h> void c() { printf("function c\n"); } abc.h...

Question Bank 14.1 What is Kernal? Describe the steps involved in booting. 14.2 Describe how the user and kernel space is divided and used in UNIX operating system. 14.3 What are system calls? Describe any two system calls and the action taken when the calls are made. How is the system calls used in application programs? 14.4 Describe the role of a scheduler. 14.5 Explain user interface and process management in UNIX. 14.6 What are the Kernel's responsibilities to facilitate I/O transfer?

Question Bank 13.1 Write a shell script which will list the files that correspond to c programs and have an extension (.c) in it. 13.2 Write a shell script that will display the setting of your path variable. 13.3 Suppose you are in your home directory which has sub-directories dir-1, dir-2, dir- 3, dir-4 and dir-5. Write a shell script which uses touch command in it to create files fil-i in dir-i for i taking values from 1 to 5. 13.4 Write a shell script that will display five most recently modified files. 13.5 Write an interactive shell script which will wait to accept a message from you and then promptly responds with “thanks for your communication”. 13.6 Write a shell script that accepts a file name from the user as a command line argument and then outputs the information when it was last modified. 13.7 Suppose in the current directory, amongst other files we have k files by name file1, file2, … filek where we do not know the value of k. Write a shell script that shall append these...

Question Bank 12.1 How can we make the AWK to respond case insensitive to case. 12.2 Suppose we create a phone directory of friends with family name, first name and phone number on each line. How shall we use AWK to determine which is the most commonly occurring family name in our phone directory? 12.3 Suppose in for the phone directory generated for question above, we additionally have a field city. How can be use AWK to get a count of friends in each city? 12.4 Suppose the tax deduction is done as follows: a. If an employee has a salary of Rs. 5000/- p.m. or less the tax is not deducted b. If the salary is between Rs. 5000/- and 10000/- p.m. and the age is over 55 years then also the tax is not deducted. c. In the case the salary is higher than the “no-tax” limits as defined in a and b above then the tax is deducted at 30% for the excess income for the first slab of Rs.10000/- and 40% of the remaining. How will you write an AWK program to process a file that has employee salary detai...

Question Bank 11.1 Which of the following commands are filters: a. ls b. ps c. egrep d. who e. find 11.2 Suppose you have a phone file with names and associated phone number in each line. Can you use grep command to locate a friend’s phone number? How? 11.3 List all the files in the current directory with names not exceeding two characters. 11.4 How can we enforce restricting the search to the last 10 lines of the file in the phone file described in 1 above. 11.5 Suppose a system has several user logged on – how will you find if your friend is logged on to the system? 11.6 Suppose there are a large number of users who are logged on to the system. We need to sort the users in the order of their login time. How should we proceed if we only need to know the user who logged on earliest amongst them? 11.7 What is the use of "find" command in UNIX environment? What are the options available with find command and how are the options utilized? 11.8 What is the difference between the ...

Question Bank 10.1 Follow the sequence given below: a. Use editor vi to create a 10 line text file called tfile. b. To this append the following line: The quick brown fox jumped on lazy dog. c. Move the cursor to the top and yank the first two line to the bottom of the page. d. Give an edit command to search for the string “lazy” and replace it by a string “not so lazy a”. e. Undo the last step. f. Delete the 4th and 5th lines. 10.2 Follow the steps in sequence given below a. Create a directory called Level1 in your directory b. Create a directory called Level2 under Level1 and change directory to Level2 c. Create a text file called tfile under the directory Level2 d. Copy the file tfile in the directory Level1 e. While you are still in directory Level2, list the contents of directory Level1. 10.3 Repeat question no. 10.2 with the modification of step d modified to read as follows: a. Create a link to tfile in directory Level1. 10.4 Like me you too have a problem of "roll-over...

Question Bank 9.1 What is vulnerability? 9.2 What is a security breach? Give two examples to illustrate a security breach. 9.3 What is a logic bomb? How it may manifest it self? 9.4 What precautions need be taken by a user in choosing password? Suggest a way to choose a good password. 9.5 What is authentication? Describe the authentication protocol you experience in using an ATM (automatic teller machines used by banks). 9.6 How does OS provide for security? What are the ways in which a systems' security may be compromised? 9.7 Differentiate between protection and security in the file system. . 9.8 Explain any two ways in which a password can be maintained. 9.9 Describe the process of encryption. What is public Key encryption? 9.10 Gives names of at least two agencies in the area of security standards and services. 9.11 Consider three sets of users, professor, TA and student. There exists a folder marks to which only professor can write into and student and TA can only read from. T...

Question Bank 8.1 From point of view of requirements, how is a real-time operating system different from general purpose operating system? 8.2 What is a hard real-time system and how can we differentiate it from a soft realtime system? 8.3 How does a device drive in a RTOS differ from the usual? 8.4 What is a micro-kernel? 8.5 What is an embedded system? Give at least two examples of embedded systems. 8.6 Describe the general strategy to define priority structure in a RTOS. 8.7 How does one determine “schedulability” in RTOS? In which context it is required? 8.8 Describe the following policies. a Earliest deadline first b Least laxity first 8.9 What is rate monotonic scheduling? When is its use recommended? 8.10 Define the essential properties of the following types of operating systems. a Real time b Hand held c Main frame d Tightly coupled system 8.11 What is priority inversion? How does it manifest it self in practice? 8.12 How can one resolve the problem of priority inversion? 8.13...

Question Bank 7.1 What is the motivation for establishing inter-process communication? 7.2 What are system calls? Explain the system call flow with the help of a block diagram. 7.3 How is a new process spawned? How does one populate code in a newly spawned process? 7.4 Describe at least three environmental variables that are carried by the child process from the description of parent process. 7.5 Differentiate between different exec system calls. 7.6 What are the limitations of a pipe as an IPC mechanism? 7.7 How is a shared file mechanism implemented to achieve IPC? 7.8 How is the shared memory model implemented to achieve IPC? 7.9 How is message based IPC achieved? 7.10 When a process receives a signal, it may respond in a variety of ways. Give an explanation of at least three different ways in which a process may respond. 7.11 What is a mail box and how it may be utilized for IPC. 7.12 What is a “port” and how it is utilized for establishing inter process communication? 7.13 What ar...

Question Bank 6.1 What is mutual exclusion? Depict a scenario where mutual exclusion is required. 6.2 What is a dead-lock? List the necessary conditions for a deadlock to occur. 6.3 Bring out the difference between Deadlock avoidance and deadlock prevention scheme. 6.4 Explain why having multiple copies of a resource does not prevent deadlocks from happening. 6.5 Define the critical section problem and explain the necessary characteristics of a correct solution. 6.6 With the help of the model of resource management, explain the tasks and goals of the resource manager. 6.7 When does deadlock happen? How does Banker’s algorithm avoid the deadlock condition. 6.8 Explain critical region and mutual exclusion with respect to produce consumer problem. 6.9 What are semaphores? What are binary semaphores? 6.10 When do we need semaphores with structures like a semaphore array? In which applications do we need to use structured semaphores? 6.11 Write the algorithms for wait() and signal() functio...

Question Bank 5.1 What are the main issues in IO management? Explain the differences in IO for human interaction as opposed to devices that communicate on-line. 5.2 Explain clearly how the devices are attached to the CPU and main memory through a bus and controllers. 5.3 What are the different modes of Interrupt? How is polling achieved? 5.4 What is the difference between polling of devices and programmed mode of I/O? 5.5 Explain the difference between an internal interrupt and a software interrupt. 5.6 Explain how interrupt is handled in Linux implemented using 8086 family of processors. 5.7 How is the interrupt enabled and detected? 5.8 What is an interrupt vector? How is the interrupt service obtained with vectored interrupt? 5.9 How is the DMA set up? 5.10 What is a device driver? Give a schematic explaining how a device driver helps establish device communication. 5.11 Explain the concept of buffering? How is the double buffering scheme organized? 5.12 Explain the concepts of spoo...

Question Bank 4.1 What is the motivation for main memory management? 4.2 What is the impact of fixed partitioning on fragmentation? 4.3 Give the relative advantages and disadvantages of load time dynamic linking and run-time dynamic linking. Differentiate them from static linking. 4.4 Explain the process of linking and loading? 4.5 Give arguments to support variable partitioning for main memory management. 4.6 How would you classify the buddy system of memory allocation? Write a short critique on the scheme. 4.7 What is meant by virtual memory? With the help of a block diagram explain the data structures used. 4.8 Describe first-fit and best-fit strategies for disk space allocation, with their merits and demerits. 4.9 What is a page and what is a frame. How are the two related? 4.10 What is swapping? Why does one need to swap areas of memory? 4.11 Discuss virtual memory management scheme. Compare any two page replacement policies 4.12 Explain the software and hardware methods of implem...

Question Bank 3.1 What is the difference between a program and a process? 3.2 What is CPU utilization? 3.3 What is the motivation for a. Multi-programming and b. Time sharing. 3.4 What is “response time”? 3.5 With the help of a state transition diagram, explain various states of a process. 3.6 What is a zombie process and how it may manifest itself? 3.7 Explain the architecture of the simple operating system employing queue data structures? 3.8 Describe a queue based state transition model. Assume that OUR_OS, a new OS is designed to support processes with two levels of priority “high” and “low”. a. How would you redraw the queue based state transition model? b. If we have additionally, three devices that provide the services in FCFS c. Mode then how will we modify the state transition diagram. 3.9 Explain the difference between busy waiting and blocking. 3.10 Explain the role of a Process control block (PCB). 3.11 Show the changes in the process control Block(PCB) when a. A new proces...

Question Bank 2.1 For the file extensions given below indicate the corresponding file type and the usually associated purpose. a. BAT , exe, zip, au b. bin, lib, tex, gif, ar 2.2 Describe the file system organization. Describe how file hierarchy is managed? 2.3 Describe at least three file operations. 2.4 Interpret the following instructions: a. ls -a , b. rm a* c. cp ?aa* ?ab* 2.5 What is the short cut to move up one level from current directory? 2.6 What happens when you give a command: touch a_file? 2.7 Describe the interpretation of the following under the command chmod: a. 444 b. 111 001 101 2.8 Describe an encryption method provided in Unix to secure files. How does one retrieve an encrypted file using an encryption command? Explain the basic principle. 2.9 Describe briefly a. The methods of file accessing. b. Two level directory structure. 2.10 What is the role of an inode? 2.11 Describe the structure of Inode in UNIX. What entries undergo changes when a file is opened to read /...

Question Bank 1.1 What is an operating system? What are the functions of the operating system? 1.2 Describe the users view of the operating system. 1.3 Name two devices that are used as input devices only. Name two devices that are used as output devices only. Name at least one device that can be used as an input as well as output device. 1.4 Explain the difference between multi-programming and time sharing. 1.5 When do we say a system is "multi-programming"? When do we say it is an "online" system? 1.6 Give an example of an operational environment when the system would have to be both multi-programming and on-line system. 1.7 Explain the difference between platform and environment. 1.8 What are some of the options available in UNIX command ps? Give description of at least two options. 1.9 Give examples of at least two applications which in your opinion are real-time applications. Support your example with appropriate rationale. 1.10 Enumerate all the HCI support yo...

Linu x Installation Amongst various flavors of UNIX, Linux is currently the most popular OS. Linux is also part of the GNU movement which believes in free software distribution. A large community of programmers subscribe to it. Linux came about mainly through the efforts of Linus Torvalds from Finland who wanted a UNIX environment on his PC while he was a university student. He drew inspiration from Prof. Andrew Tanenbaum of University of Amsterdam, who had earlier designed a small OS called Minix. Minix was primarily used as a teaching tool with its code made widely available and distributed. Minix code could be modified and its capability extended. Linus Torvalds not only designed a PC-based Unix for his personal use, but also freely distributed it. Presently, there is a very large Linux community worldwide. Every major university, or urban centre, has a Linux group. Linux found ready acceptance and the spirit of free distribution has attracted many willing voluntary contributors....

DEVICE DRIVERS ON LINUX Introduction: Most of the Linux code is independent of the hardware it runs on. Applications are often agnostic to the internals of a hardware device they interact with. They interact with the devices as a black box using operating system defined interfaces. As far as applications are concerned, inside the black box sits a program that exercises a protocol to interact with the device completely. This program interacts with the device at a very low level and abstracts away all the oddities and peculiarities of the underlying hardware to the invoking application. Obviously every device has a different device driver. The demand for device drivers is increasing as more and more devices are being introduced and the old ones become obsolete. In the context of Linux as an open source OS, device drivers are in great demand. There are two principal drivers behind this. Firstly, many hardware manufacturers do not ship a Linux driver so it is left for someone from the o...

Linux File Systems Introduction: Linux retains most fundamentals of the Unix file systems. While most Linux systems retain Minix file systems as well, the more commonly used file systems are VFS and ext2FS which stand for virtual file system and extended file systems. We shall also examine some details of proc file system and motivation for its presence in Linux file systems. As in other UNIXES in Linux the files are mounted in one huge tree rooted at /. The file may actually be on different drives on the same or on remotely networked machines. Unlike windows, and like unixes, Linux does not have drive numbers like A: B: C: etc. Th e mount operation : The unixes have a notion of m ount operation. The mount operation is used to attach a filesystem to an existing filesystem on a hard disk or any other block oriented device. The idea is to attach the filesystem within the file hierarchy at a specified mount point. The mount point is defined by the path name for an identified directory....