Csc 221 Computer Programs PDF

CSC 221 (Ayeni S.) SYSTEM AND APPLICATION PROGRAM Computer Programs Definition: Computer software is a set of programs and procedures that are intended to perform specific tasks on a computer system. There are mainly two types of computer software: System Software and A...

CSC 221 (Ayeni S.) SYSTEM AND APPLICATION PROGRAM Computer Programs Definition: Computer software is a set of programs and procedures that are intended to perform specific tasks on a computer system. There are mainly two types of computer software: System Software and Application Software Computer Programs 2 Computer Programs Computer Software is a collection and integrated computer programs which perform specific task or generic tasks. Software can be written using a low level language such as assembly language Software can also be written using a high level language such a C, C++, C#, Java or Fortran Computer Programs 3 Computer Programs Computer programs are set of instructions that helps the user manage the resources of the computer system. Computer system resources can also be referred to as the computer hardware These Hardware resources include the following: Computer Programs 4 Computer Programs Central Processing Unit (CPU) Memory (RAM-Random Access Memory) Registers Storage(Hard drive) Arithmetic and Logic Unit (ALU) Peripheral Devices - Keyboards - Mouse - Monitor or Visual Display Unit Computer Programs 5 Computer Programs Ports - USB Port - Serial Port - Parallel Port Cache Memory Control Unit ROM (Read Only Memory) Computer Programs 6 System Programs System program/software is a category of computer software which interface between the application software and the computer hardware In other words system software allocates the resources of the computer system to the application program(s) currently running on the computer system Computer Programs 7 System Programs For instance the computer system may run two(2) or more application programs at the same time-such as a VLC media player and a word processor Then the question is how does the computer manages the two application programs currently running on the computer system at the same time? Computer Programs 8 System Programs So, the system software does that; how? By allocating the computer system hardware resources such as CPU, Memory, Storage and Registers to the two application programs using a scheduling algorithm. An example of the system software is the Operating System Computer Programs 9 System Programs The Operating system is a powerful system software and the most important system software in the computer system Without the operating system your computer can not run Examples of system software includes: Computer Programs 10 System Programs 1) Operating System 2) Device Drivers 3) Utility Programs 4) Language Processors 5) Firmware (e.g. BIOS) Computer Programs 11 System Programs A reason why you need an operating system to interface between application program and computer hardware is because the native language the computer operates on is the machine language Machine language is a low level language which represents data and instructions in zero’s (0’s) and One’s (1’s)- a binary system Computer Programs 12 System Programs For example the table below show the binary equivalence of numbers: Decimal Binary 1 0001 2 0010 3 0011 4 0100 5 0101 Computer Programs 13 Operating Systems The operating system is the most important system software in the computer system The operating system starts working as soon as the system is switched on and stops only when you switch it off When you power on your computer system, the BIOS then starts the boot sequence. It looks for the operating system in a storage. Computer Programs 14 Operating Systems The BIOS will then fetch the operating system from the storage (e.g. hard drive) and load it into the RAM The BIOS then transfers control to the operating system until you power off your computer Computer Programs 15 Operating Systems The BIOS is Basic Input/output System which is a firmware that interface between the computer hardware and the operating system Topics/concepts of interest in operating system include: - Basic principles of operations - Features of operating system Computer Programs 16 Operating Systems - Types of operating system - Examples of operating system - Functions of operating system - Process - Deadlock - Resources management Computer Programs 17 Operating Systems Functions of operating system - Resources management - Process management - File management - Deadlock handling - Creating and managing virtual memory Computer Programs 18 Operating Systems Examples of operating system - Window OS - Linux OS - Unix OS - DOS - Android OS Computer Programs 19 Operating Systems The figure below shows the operating system managing the access of more than one application programs to the computer hardware Computer Programs 20 Application Programs Application software is a specific purpose software Users interact directly with application software while the application software interact with the system software The system software interact with the computer hardware resources Computer Programs 21 Application Programs Hence the application software can be said to require the system software to run Without the system software you can not run the application software on the computer Examples of the application software are: Computer Programs 22 Application Programs 1) Word Processors 2) Spreadsheet 3) Presentation software 4) Database Management System Software Computer Programs 23 Word Processors A word processor such as Microsoft word can be used to create documents, letters or reports You can edit, modify and make corrections, adjustment, or amendments to your documents, letters or reports after creating them Computer Programs 24 Word Processors Examples of word processors include: - Microsoft word - Google Doc - iWork - Latex Computer Programs 25 Spreadsheets A spreadsheet is a versatile computer application program, versatile for it wide range of dynamic calculation Spreadsheet such as Microsoft excel can be used to plot or create high quality graphs and charts such as pie charts, bar charts and histograms Computer Programs 26 Spreadsheets Typically a spreadsheet application has worksheets arranged into workbooks Each worksheet has a page layout or a work space of rectangular grid of rows and columns Hence you have cells, each cell can hold or store at least a value Computer Programs 27 Spreadsheets The value stored could be an integer number such as 2, 10, or 100 or a real/floating point number such as 2.12, 10.56 or 100.26 You can the complete a computational task of simple or complex mathematical calculations on the data when the formula to use is known Computer Programs 28 Presentation Software It is an application software program that allows you to create electronic slide shows It is used to present information in a organized manner to an audience in a meeting, class or conference In slide you can insert text, clip art, sound clips, movie clips, graphs, organizational charts, imported web screens and pictures Computer Programs 29 Presentation Software You can easily create a presentation and convey your message clearly and logically to your audience Computer Programs 30 Database Management Software Database Management System (DBMS) is a software program that controls the organization, storage, management and retrieval of data in a database Examples include MySQL, SQLite and MS Access Computer Programs 31 Database Management Software The DBMS makes the manipulation of data involving data retrieval and data update possible via query languages such as SQL Features of a DBMS include: Data integrity, Data security, Backup and recovery, Concurrency control, Data mining and Data sharing Computer Programs 32 Computer Operations The computer system is versatile for the following types of operations - Calculations - Logical functions - Text manipulation Computer Programs 33 Computer Instructions Instructions tell the computer what to do at a particular time Usually one task per instruction Examples - Sub a, b - add a, b Computer Programs 34