SOFTWARE CONCEPTS

1. SOFTWARE CONCEPTS

2. Application software :- The software that controls internal computer operations . • Application software :- an application software is the set of programs necessary to carry out operations for a specified application . TYPES OF SOFTWARE

3. System software can further classified into two categories :- • Operating system :- an operating system is a program which acts as an interface between a user and the hardware (i.e., all computer resources). • Language processor :- 1. assembler 2. interpreter 3. compiler SYSTEM SOFTWAE

5. Application software can further classified into three categories :- 1.packeges 2.utilities 3.customised software APPLICATION SOFTWARE

6. In earlier day’s user had to design the application according to the internal structure of the hardware. Operating System was needed to enable the user to design the application without concerning the details of the computer’s internal structure. In general the boundary between the hardware & software is transparent to the user. The need of operating system

7. 1. Easy interaction between the human & computer. • 2. Starting computer operation automatically when power in turned on. • 3. Loading & scheduling users program. • 4. Controlling input & output. • 5. Controlling program execution. • 6. Managing use of main memory. • 7. Providing security to users program.

9. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between application programs and the computer hardware, although the application code is usually executed directly by the hardware and will frequently call the OS or be interrupted by it.

10. No matter what operating system you pick today, whether it is the most popular Linux distributions, Windows or Mac, you will find that it has lots of bloat and garbage shoved in there for no real reason except to add supposed value to that operating system. • Be honest now, how many of you who use windows actually use note or WordPad? I will bet ten bucks to the dollar that (note. this is just a figure of speech, not an actual bet. I'm just a poor boy in a poor family :) )that in place of note you download some program with more functionality and in place of WordPad you use some office program. Don't get me started on internet explorer either.

11. The fact of the matter is, if you could remove all the un-needed and unwanted junk and bloat from any operating system you would be left with a lean, mean computing machine which requires far less hardware resources than what is needed today. As far as I know there is only one operating system with which you can do that but I am not writing this to promote that particular, albeit excellent, operating system.

13. The fact of the matter is, if you could remove all the un-needed and unwanted junk and bloat from any operating system you would be left with a lean, mean computing machine which requires far less hardware resources than what is needed today. As far as I know there is only one operating system with which you can do that but I am not writing this to promote that particular, albeit excellent, operating system.

14. Back to the title question, why do we need an operating system? Why not have our programs interact directly with the hardware? They would run much better and not need as much ram.  • Back in the dawn of computing they did just that. There was no operating system. Programs were written for a computer and those programs interacted directly with the hardware. They ran fast, they ran lean and they could only run on that machine.

15. This is why an operating system is needed. It allows a program to run on multiple different types of hardware. An operating system provides a layer between the program and hardware to enable a program to use a standard interface no matter what hardware is used. The operating system translates the software calls to the hardware calls for that particular piece of hardware.

17. Sure this slows things down a bit and uses more resources however the benefits are great. What is gained is increased flexibility and greater range of scope for a particular program. If it weren't for the operating system then computers would not be as wide spread as they are today.

18. In the in the working of a modern computer system, memory plays a central role. As both CPU and I/O system interacts with memory. Memory is large array of words or bytes, each with its own address. The CPU reads from and writes to specific memory addresses. STORAGE MANAGEMENT

19. A program must be assigned some memory area and loaded into memory in order to be executed. As the program executes, it accesses program instructions and data from memory by generating addresses from the allocated memory. When the program terminates, its memory space is declared free, and the next program may be given the same memory area.

21. In this classical approach, each problem, which is to be executed, is allocated a contiguous storage memory. At every job step initiation, the OS has to ensure that sufficient contiguous area is available to accommodation. Contiguous Storage Allocation

22. In non contiguous storage allocation, a program can be stored in non contiguous memory areas. A program is divided into smaller components of equal sizes. One of more components can be stored in the non contiguous memory areas. Each component in that particular memory area is provided addresses 0, 1, 2....n. for example; a program P x requires 90k memory for its execution. Non Contiguous Storage Allocation

23. Now that, we have seen, that a program can be stored at non contiguous locations, suppose even if we use all available free memory area still the program cannot be loaded into main storage because the total free memory is still less than the size of the program. Virtual storage helps one perform such an execution, which is being covered in the next section. Two main approaches to virtual storage are 1.Program-paging 2.Program segmentation • In paging, the computer system is responsible for silting a program into program segments called pages whereas in segmentation approach, the program identifies the logical entities in the program and declare the as program components.

25. In paging, each programs split into fixed size program component called pages. Pages in a program, and words in page, both are numbered from 0.....n, i.e., their logical address space. • In order to execute a program, some pages of it are loaded in the main memory depending upon the storage availability. During its execution, the program generates page number which is mapped to find its physical location. Virtual Storage Using Paging

26. When the required page is not in main storage, an interrupt, known as missing page interrupt, is raised. The OS now takes action by bringing the required page from the secondary storage into an empty page block; this operation is called page-in.

27. This scheme is implemented in the same manner as paging is implemented. The point where it differs from paging is, us of program segment. A program segment is a logical unit of program as defined by programmer. • For accessing a particular word in the segment, its logical address consists of two parts: • (i) segment number and (ii) word number. Virtual Storage Using Segmentation

29. This segment number is mapped on to segment table to physical address of the segment and by adding the words identification number, physical or actual address of the words found out. Again the hardware unit, Address Transformation Unit, is responsible for actual address of the of required word within segment. • To increase the efficiency of a system sometimes paging and segmentation is combined. Now within this paging can be implemented, making Swapping possible. It improves the efficiency of the system as access of page within segment and word in a page. For each segment, a separate PMT ( page map table) is maintained.

30. A computer system works with ‘information’. It stores information, processes information, provides information etc. this information management component of OS is structured as follows: • Physical IOCS ( Input Output Control System ) is responsible for device management for ensuring device independence. It provide a basic capability for the program to perform their own IO. • Logical IOCS is responsible for efficient organisation and access of data on IO device. It provide a basic capability for the file definition, choice of method and access methods. • File System is responsible for protection and controlling sharing of files. INFORMATION MANAGEMENT

31. The major functions of file system are given below : • It provide file naming freedom to the users. • Provide long and short term storage of files by allowing operations • Provide safety of content by supporting file access permissions. • Provide security against loss of information.

33. Linux • Linux is the name of a popular computer operating system. It is the most famous example of free software and open source development, as it is not only freely available, but also its underlying source code is available to all and anyone can freely openly use it, modify it and redistribute it. • The Linux kernel was written originally by a Finnish university student Linux Thorvaldsen. Linux is one very popular operating system, supported by many big manufactures and vendors. Linux can be downloaded from www.linux.org. • Linux is part of the popular web server set of program – LAMP (Linux, Apache, My SQL and PHP). Some commonly used operating systems

34. Windows • Microsoft Windows is the name of several families of GUI (Graphical User Interface) operating systems by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 in response to the growing interest in graphical user interfaces (GUIs). Microsoft Windows came to dominate the world’s personal computer market, overtaking Mac OS, which had been introduced previously. The most recent client version of Windows in Windows 7.

35. BOSS (Bharat Operating System Solutions) Linux • BOSS (Bharat Operating System Solutions) Linux is an Indian distribution of GNU/Linux based on the Debi an. It consists of the Linux operating system kernel, office application software suite BharteeyaOO, Internet access software (e.g., Firefox (web browser), Thunderbird (email), Pidgin (chat) etc.), and file sharing/converter and multimedia applications have been localized to enable the use of Indian languages.

37.  Solaris • The Solaris Operating System, usually known simply as Solaris, is a free Unix-based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS. • Mobile Operating Systems • These days mobile devices have turned smart, courtesy smart mobile operating systems. We are discussing below some most popular mobile operating systems. • Android.Android OS is a Linux- based platform for mobile phones. Android was released under the Apache v2 open source license. Google and the Open Handset Alliance (OHA), a coalition of hardware, software and telecommunications companies, have developed Android.

38. Windows Phone.Windows Phone7 is a mobile operating system developed by Microsoft, and is the successor to its Windows Mobile platform, although incompatible with it. Windows Phone 7 was Microsoft’s answer to the flourishing smart-phone world. • Apple iOS. iOS (known as phones OS before June 2010) is Apple’s mobile operating system. It is exclusively for Apple’s smart devices like phones, iPods and iPod touch etc. • RIM Blackberry OS. Blackberry OS used in all Blackberry devices such as Blackberry phones and play-books, is developed by the Research In Motion (RIM) – a Canadian Global telecommunications company. • Blackberry’s latest OS is called QNX which is set to replace the older BlackBerry OS.

39. THE END

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41. MADE BY :- 1. AASTHA 2. BHUMIKA 3. GOURAV 4. HARSH 5. JATIN 6. KANISHKA GROUP II