Materials prepared by Dhimas Ruswanto, BMm Skill Area 310 – Part B Materials prepared by Dhimas Ruswanto, BMm

Lecture Overview CPU Main Memory User Interface Systems Software Concepts Utility Programs

Computer System Processing (CPU/Memory) Input Devices Output Devices Storage Devices

CPU Also called CPU, processor or microprocessor “Brains” of the computer Performs all computer operations

Main Memory Where all the input data and results stored Random Access Memory (RAM) Read Only Memory (ROM)

RAM RAM is volatile = data are lost when computer is turned off Read current info and also write new info Very important in determining capabilities of the computer system Stores work when they are in use. Word Document Spreadsheet Power Point

ROM ROM is non-volatile = permanent and are not affected where computer is turned lost Can read info Stored in ROM Can not write new info into ROM Used for “internal workings” of computer Boot Software

User Interface A function of the operating system that allows individuals to access and command the computer Command-based User Interface A particular user interface that requires text commands be given to the computer to perform basic activities E.g., unix, DOS Graphical User Interface (GUI) A user interface that uses pictures (icons) and menus displayed on the screen to send commands to the computer system Input Devices -> keyboard, mouse, monitor, touch-screen Features of GUI -> Windows, Icons, Menus, Pointer

Systems Software Concepts Hardware Independences Memory Management Processing Tasks Networking Capability Access to System Resources and Security File Management

Systems Software Concepts Hardware independence Operating system (OS) provides hardware independence for application software Application software interfaces (API) with the operating system which interfaces with the hardware Memory management Control how memory is accessed and maximize available memory and storage

API Application Programming Interface (API) A language and message format used by an application program to communicate with the operating system or some other control program such as a database management system (DBMS) or communications protocol Application Program Interface Links Application Software to the Operating System

Systems Software Concepts Processing Tasks Multitasking / Multiprogramming: More than one program in RAM at the same time Allows more than one active user program to be stored in main memory simultaneously Fairly sophisticated All the jobs that enter the system are kept in the job pool. This pool consists of all processes residing on mass storage awaiting allocation of main memory. If there is not enough room, then the system must choose among the jobs. A time-sharing system is a multiprogramming system.

Processing Tasks (cont’d) Time-Sharing Sharing of a computing resources among many users by means of multiprogramming Allowing a large number of users to interact concurrently with a single computer Dramatically lowered the cost of providing computing capability Made possible for individuals and organizations to use a computer without owning one Promoted the interactive use of computers and the development of new interactive applications

Systems Software Concepts Networking Capability Features and capabilities of the OS that aid users in connecting to a computer network Allow connected computers to: Communicate Share resources Divide work

Systems Software Concepts Access to system resources and security Protection against unauthorized access Logins and passwords File management Ensures that files in secondary storage are available when needed and that they are protected from access by unauthorized users

Utility Programs Help to perform maintenance or correct problems with a computer system. Designed to limited range of tasks E.g. : Hardware utilities, Virus-detection Recovery utilities File-compression utilities, Spam and pop-up blocker utilities

Summary CPU is a ‘brain’ of a computer Main Memory: User Interface RAM (volatile) & ROM (non-volatile) User Interface Command-based User Interface Graphical User Interface Systems Software Concept: Hardware Independences Memory Management Processing Tasks Networking Capability Access to System Resources and Security File Management