AKTU 1st Year Sem 2 Solved Paper 2015-16 | COMP. SYSTEM & C PROGRAMMING | Sec A

Paper download link: Paper | Sem 2 | 2015-16

B.Tech.
(SEM-II) THEORY EXAMINATION 2015-16
COMPUTER SYSTEM & PROGRAMMING IN C

Time: 3hrs
Total Marks: 100

Note:-

• There are three sections. Section A carries 20 marks, Section B carries 50 marks and Section C carries 30 marks.
• Attempt all questions. Marks are indicated against each question.
• Assume suitable data wherever necessary.

Section – A

1. Attempt all parts: (2*10 = 20)

1. Give the layout of a typical C program.
   
   The structure of a C program is as follows:

   

   1. Header Files Inclusion
   2. Main Method Declaration
   3. Variable Declaration
   4. Body
   5. Return Statement
2. What do you mean by Algorithm?
   
   The word Algorithm means “a process or set of rules to be followed in calculations or other problem-solving operations”. Therefore Algorithm refers to a set of rules/instructions that step-by-step define how a work is to be executed upon inorder to get the expected results.
3. What are the various components of Operating System?
   
   An operating system has variety of functions to perform. Some of the prominent functions of an operating system can be broadly outlined as:
   • Processor Management: This deals with management of the Central Processing Unit (CPU). The operating system takes care of the allotment of CPU time to different processes. When a process finishes its CPU processing after executing for the allotted time period, this is called scheduling. There are various type of scheduling techniques that are used by the operating systems:
     1. Shortest Job First(SJF): Process which need the shortest CPU time are scheduled first.
     2. Round Robin Scheduling: Each process is assigned a fixed CPU execution time in cyclic way.
     3. Priority Based scheduling (Non Preemptive): In this scheduling, processes are scheduled according to their priorities, i.e., highest priority process is schedule first. If priorities of two processes match, then schedule according to arrival time
   • Device Management:
     The Operating System communicates with hardware and the attached devices and maintains a balance between them and the CPU. This is all the more important because the CPU processing speed is much higher than that
     of I/O devices. In order to optimize the CPU time, the operating system employstwo techniques – Buffering and Spooling.
   • Buffering:
     In this technique, input and output data is temporarily stored in Input Buffer and Output Buffer. Once the signal for input or output is sent to or from the CPU respectively, the operating system through the device controller moves the data from the input device to the input buffer and for the output device to the output buffer. In case of input, if the buffer is full, the operating system sends a signal to the program which processes the data stored in the buffer. When the buffer becomes empty, the program informs the operating system which reloads the buffer and the input operation continues.
   • Spooling (Simultaneous Peripheral Operation on Line):
     This is a device management technique used for processing of different tasks on the same input/output device. When there are various users on a network sharing the same resource then it can be a possibility that more than one user might give it a command at the same point of time. So, the operating system temporarily stores the data of every user on the hard disk of the computer to which the resource is attached. The individual user need not wait for the execution process to be completed. Instead the operating system sends the data from the hard disk to the resource one by one.
     Example: printer
   • Memory management:
     In a computer, both the CPU and the I/O devices interact with the memory. When a program needs to be executed it is loaded onto the main memory till the execution is completed. Thereafter that memory space is freed and is available for other programs. The common memory management techniques used by the operating system are Partitioning and Virtual Memory.
   • Partitioning:
     The total memory is divided into various partitions of same size or different sizes. This helps to accommodate number of programs in the memory. The partition can be fixed i.e. remains same for all the programs in the memory or variable i.e. memory is allocated when a program is loaded on to the memory. The later approach causes less wastage of memory but in due course of time, it may become fragmented.
   • Virtual Memory:
     This is a technique used by the operating systems which allow the user can load the programs which are larger than the main memory of the computer. In this technique the program is executed even if the complete program can not be loaded inside the main memory leading to efficient memory utilization.
   • File Management:
     The operating System manages the files, folders and directory systems on a computer. Any data on a computer is stored in the form of files and the operating system keeps information about all of them using File Allocation Table (FAT). The FAT stores general information about files like filename, type (text or binary), size, starting address and access mode (sequential/indexed sequential/direct/relative). The file manager of the operating system helps to create, edit, copy, allocate memory to the files and also updates the FAT. The operating system also takes care that files are opened with proper access rights to read or edit them.
4. Convert the octal number 2354 to equivalent hexadecimal number.
   
   (2354)₈
   = (010 011 101 100)₂ (on converting to Binary)
   = (0100 1110 1100)₂ (on grouping by 4 bits)
   = (4EC)₁₆ (on converting to Hexadecimal)
5. Write short note on Android Operating System.
   
   Android is an operating system which is build basically for Mobile phones. It is based on the Linux Kernel and other open sources softwares and is developed by Google. It is used for touchscreen mobile devices such as smartphones and tablets. But nowadays these are used in Android Auto cars, TV, watches, camera, etc. It has been one of the best-selling OS for smartphones. Android OS was developed by Android Inc. which Google bought in 2005. Various applications (apps) like games, music player, camera, etc. are build for these smartphones for running on Android. Google Play store features more than 3.3 million apps. The app is developed on an application known as Android Studio. These executable apps are installed through a bundle or package called APK(Android Package Kit).
6. Give architecture of UNIX
   
   
   Figure – system structure
   • Layer-1: Hardware –
     It consists of all hardware related information.
   • Layer-2: Kernel –
     It interacts with hardware and most of the tasks like memory management, task scheduling and management are done by the kernel.
   • Layer-3: Shell commands –
     Shell is the utility that processes your requests. When you type in a command at the terminal, shell interprets the command and calls the program that you want.
     There are various commands like cp, mv, cat, grep, id, wc, nroff, a.out and more.
   • Layer-4: Application Layer –
     It is the outermost layer that executes the given external applications.
7. Differentiate between RAM and ROM.
   
   
8. What do you mean by Software?
   
   Software is a program or set of programs containing instructions which provide desired functionality.
9. Write short note on Structured Programming.
   
   Structured Programming Approach, as the word suggests, can be defined as a programming approach in which the program is made as a single structure. It means that the code will execute the instruction by instruction one after the other. It doesn’t support the possibility of jumping from one instruction to some other with help of any statement like GOTO, etc. Therefore, the instructions in this approach will be executed in a serial and structured manner. The languages that support Structured programming approach are:
   • C
   • C++
   • Java
   • C#

   ..etc

10. Define storage class in ‘C’
    
    Storage Classes are used to describe about the features of a variable/function. These features basically include the scope, visibility and life-time which help us to trace the existence of a particular variable during the runtime of a program.

    C language uses 4 storage classes, namely:

    • auto
    • extern
    • static
    • register