INTRODUCTION SOFTWARE HARDWARE DIFFERENCE BETWEEN THE S/W AND H/W

TYPES OF SOFTWARE APPLICATIONSYSTEM SOFTWARE

Application software -Easy-to-use programs designed to perform specific tasks. System software -Set of programs designed to operate and control the computer.

OPERATING SYSTEM It is a collection of programs that controls and manages the computer Examples Windows, Unix, MSDOS

Functions Of OS It provide an interface between the hardware and the user. It controls and co-ordinate the entire computer system. It controls the allocation and use of various resource by various user and task. It controls the various application programs. Scheduling the jobs. Process management, Memory management, Device management etc,.

TYPES OF OS Single user/ single tasking OS Single user/ multi tasking OS Multi user/ multi tasking OS Time sharing OS Virtual storage OS Real time system

Single user/Single tasking OS One user works on the system Performs one task at a time Take up little space on disk Run on inexpensive computers Example MS-DOS

Single user/Multitasking OS User performs many tasks at once Most common form of OS Require expensive computers Tend to be complex Example: Windows XP

Multi user/Multitasking OS Many users connect to one computer Each user has a unique session Maintenance can be easy Requires a powerful computer Example: UNIX, Linux, etc,.

Time sharing OS It handles multiple jobs at a time. It switches the CPU among various jobs that are running on the computer whenever there is a program break or a fixed time has expired.

Virtual storage OS It uses the technique Demand paging. i.e. whenever the program size is larger than the main memory it splits the program into many pages. Only the needed page is loaded to the main memory for execution.

Real-time operating system It gets data from an on going event. Respond quickly to user input. Example: Reservation system

LOGICAL SYSTEM ARCHITECTURE

HARDWARE The physical components present in the computer is called Hardware. Example: Keyboard, Monitor etc,.

SOFTWARE It is a collection of programs which, performs some task. System s/w Application s/w

System S/W It is collection of programs that controls and manage the computer. Types:OS,Language processor etc,.

TYPES OF SOFTWARE APPLICATIONSYSTEM SOFTWARE Example: Operating system, Device drivers, Language Processor, System utilities etc,. Example: Ms-Office, Reservation system, Payroll processing system Hospital management system etc,. GENERAL CUSTOMISED

OS It is a collection of programs that controls and manages all the components present in the computer

Device drivers It is set of programs, which act as an interface between the computer and the device. It is responsible for the proper functioning of the device. COMPUTER DRIVERSDRIVERS DEVICE 1 DEVICE 2 DEVICE n

Language Processor It is a system s/w that translates the programs written in High level language to Machine language. Machine language: 0’s and 1’s. High level language: C, C++, Java etc,. Example: Compiler, Interpreter, Assembler

Compiler It converts the programs written in high level language to machine language i.e. it translates the source code to object code. HIGH LEVEL LANGUAGE COMPILERCOMPILER MACHINE LANGUAGE

Interpreter It converts the programs written in high level language to machine language. It executes the source code in line-by-line manner. INTERPRETREINTERPRETRE HIGH LEVEL LANGUAGE MACHINE LANGUAGE

Assembler It converts the programs written in Assembly language to machine language. ASSEMBLERASSEMBLER ASSEMBLY LANGUAGE MACHINE LANGUAGE

System Utilities These programs performs tasks related to the maintenance of computer –Example: Disk clean-up.

APPLICATION SOFTWARE It is collection of programs that performs a specific task. – Customised – General

APPLICATION SOFTWARE (Cont) Customised Application s/w It is developed to meet the requirements of limited user. General Application s/w It is developed to meet the requirements of many user.

S/W Terminologies Firmware It is a software, which is permanently stored on the memory Eg: BIOS Open source It is software developed by some programmers and released for public use The programming code is available so that the user can modify it.

S/W Terminologies (Cont) Freeware It is a copyrighted software which is given away free by the owner. Commercial s/w It is developed by business organizations to earn profit

SYSTEM DEVELOPMENT LIFE CYCLE Steps: Requirement analysis Design Coding Testing Implementation & maintenance

SDLC Requirement Analysis Impl & Maintenance Testing Coding Design

Requirement analysis It produce the Software requirement document (SRS),which specifies all requirements of the customer.

Design It is the process of designing how the requirements to be implemented.

Coding It is the process of developing code for the software.

Testing It is the process of executing the software with sample data to verify whether it has errors or not.

Implementation & maintenance It involves installation of the s/w, giving training to the customer etc,.