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Sample of interactive PDF 1 chapter 2 Software concept Unit 1 of CBSE class 11 Computer Science a) ‘Hardware is of no use without software and software cannot be used without hardware.’ Explain. Ans: The saying Hardware is of no use without software and software cannot be used without hardware is indeed true because every computer systems have both hardware and software existing together and each depend on the other. Hardware refers to the tangible part of the computer that is used to interact with the computer. Software refers to set of programs which are used to perform various on the computer and there by controlling the operations of the computer. The hardware needs software to perform its operations. Software requires hardware on which it can reside and run. Hence, only with the two co-operating can the actual working of the computer take place. b) How can the software be classified? Name at least one software in each of the categories. At a broad level, the software can be classified as follows. Ans: 1) System software. Examples include Windows, Machintosh, Linux, Android iOS, C++ compiler, Java interpreter etc. 2) Utility software. Examples include Norton Antivirus, WinZip compressor, Windows Explorer etc. 3) Application software. Examples include Office 365 suite (which includes Microsoft Word, Microsoft Excel etc), Oracle, MS SQL Server etc. The following diagram gives more detailed classification of the software. Software

Sample of interactive PDF ( A) SystemSoftware ( B) UtilitySoftware (C) Application software( A) SystemSoftware (1) OperatingSystem (2)Language Translators (2.1) Compiler (2.2) Assembler (2.3) Interpreter (C) Application software (1) General Purpose (2) Customized Software c) What is an operating system? Write names of any two popular operating systems. Ans: An operating system is a crucial part for the operation of the computer. It is the first program that is loaded into the memory as soon as the computer is switched on. It is a set of instructions and programs that monitor and regulate the working of a computer. It is also responsible to provide various services which the application software, programmers and users use. Few of the various responsibilities of the operating system are as follows: a. Managing the hardware b. Managing the software c. Input processing d. Output Processing e. Information flow into and out of the processor f. Prioritization of various tasks to be handled etc Operating system also acts as a interface which the user can interact with to communicate with the computer hardware. Few of the most popular Operating systems are Windows, Macintosh, Linux, Unix, Solaris etc d) What is the role of a Page Map Table in Virtual Memory Management? Ans:

Sample of interactive PDF d) Using the virtual memory technique, it is possible to run programs that require memory more than the main memory of the computer. While using this technique, the program is partially loaded onto the memory and starts executing. To achieve this, the operating system divides the main memory into multiple fixed-length continuous blocks called pages. A part of the large program is then loaded onto the main memory. This is known as active set. The remaining part of the program is then stored in the secondary storage device in the form of blocks or sectors or tracks. Page Map Table (PMT) helps the operating system to keep track of the mapping of in which page of main memory is storing which block of secondary memory. It uses the virtual addresses to map either the main memory or the secondary memory. e) Explain the major functions of an operating system. Ans: Few of the salient functions of the operating system are as follows: 1. Processor Management: In this, it manages the CPU through scheduling in which it allots the CPU time to different processes. Scheduling either priority scheduling in which the tasks are run based on the priority or it can be round robin/time sharing in which each task is run for a fixed amount of time. 2. Divice Management: In this, the operating system communicates with the hardware and the attached devices and maintains a balance between them and the CPU. This can be done either through buffering or overlapped processing in which the input or output data is temporarily stored in input buffers or output burffers and then sent to / from the program. Or it can be done through Spooling (Simultaneous Peripheral Operation On Line) where in the processing of different tasks on the same input/output device is managed through temporarily storing the data on the hard disk of the device and processing the tasks one by one. 3. Memory Management: The program that need to be executed is loaded into memory and then once it the program is completed executing, the memory is cleared. This can be achieved through partitioning in which the memory is divided into multiple partitions of fixed or varying lengths into which the programs are loaded and executed. Or it could be achieved through virtual memory in which the main memory is divided into equal sizes called pages and even programs which require more memory then main memory can be loaded partially

Sample of interactive PDF into memory and executed by maintaining Page Map Tables. 4. File Management: The Operating system manages file/folders/directories by maintaining File Allocation Table (FAT) which is used for storing general information about files. The file manager helps in creating, editing, copying and allocating the memory to the files and updating the FAT tables. It also handles the read/write/edit permissions of the files. f) What is the purpose of a language processor? Ans: Machine code is the only language that the computers can understand. This machine language is primitive and comprises of only zeros(0) and ones(0). However, it is very complex and tedious task for humans to write the programs in the machine language. So, we write programs in assembly language or high level languages (which are human readable) like BASIC, C++, Python, Java etc. These programs are commonly known as source program or source code. However, these programs as these programs can not be directly executed by the computers, they are translated to the machine code before running them. The special translators used for this purpose are known as language processors. g) Differentiate between: (i) An interpreter and a compiler. (ii) Priority Scheduling and Round Robin Scheduling (iii) Buffering and SPOOLING (iv) Time Sharing and Real Time Operating System Ans: The following are the differences between an interpreter and a compiler. Interpreter Compiler It translates the source program into machine code proceeding one statement at a time. It translates the whole source program into machine code all at once. The program thus translated is known as Object Code. The source program can be translated to object code only if there are no errors. The translated line is immediately executed. The program is executed only after the entire translation. If an error is encountered in a line it immediately terminates the translation.