CHAPTER 6: THE SYSTEM UNIT

SYSYEM UNIT

• known as " sysyem chassis".
• container of electronic component that make up computer system.
• 4 basic types:

        ~Desktop contain the system's electronic components and selected secondary storage. Input and output devices are located outside of system unit.

http://www.techshout.com/hardware/2008/13/acer-aspire-3450-desktop-launched-in-the-indian-market/


        ~Notebook are much smaller and portable.It often called laptops.The monitor is attached by hinges.

http://hi.baidu.com/wangzhiyun85/blog/item/793fd6180628b80035fa4142.html


        ~Table PC are highly portable devices that support stylus tp input commands and data. (a)Accepts stylus input and has monitor swivels and folds onto its keyboard.

http://www.tabletpc2.com/Archives/2005%20Archives/News-Archive-December-2005.htm

                 (b)Has removable keyboard

http://techsupport24hours.com/tech-support-for-asus-eee-pc-t91/

   
        ~Handheld is the smallest and designed to fit into the palm of one hand.The most widely used handheld computers are personal digital assistants(PDAs) and smartphones.

BINARY CODING SCHEMES

• convert binary data into characters.
• 3 such schemes:

        ~ASCII-the most widely used for microcomputers.
        ~EBCDI-developed by IBM ,used primarly by large computers.
        ~Unicode -16bit code support both ASCII and EBCDI codes and internationallanguages.

SYSTEM BOARD

• known as motherboard.
• connects all system components and allows input and output devices to communicate with system unit.
• a flat circuit board covered with these electronic components including:

        ~Sockets provide connection points for chips.A chips is also called silicon chip,semiconductor,or integrated circuit.
        ~Slots provide connection points for specialized cards or circuit boards.
        ~Bus lines provide pathways that support communication.

http://computer.yourdictionary.com/slot-1

MICROPROCESSOR

• is a single chip that contains the central processing unit(CPU).
• 2 basic components:

        ~Control Unit tells the computer system hoe to carry out program instructions.
        ~Arithmetic-logic unit(ALU)performs logical and arithmetic operations.       

http://www.shutterstock.com/pic-8145061/stock-photo-close-up-of-microprocessor-chip-on-motherboard-in-computer.html

MEMORY

• is a holding data,instructions,and information.
• 3 types momory chips:

        ~RAM is called temporary or volatile storage because their contents are lost if power is disrupted.
   (a)Cache memory-a high speed holding area for frequently used data and information.
   (b)DIMM-to expand memory.
   (c)virtual memory-divides large programs into parts that are read into RAM as needed.

http://www.tomshardware.com/reviews/ram-scaling-notebook,1920-6.html


        ~ROM are nonvolite storage and control essential system operations.

        ~Flash Memory is a type of memory that does not ose it contents when power is removed.it is used to store information about a computer's configuration.



*** Information is getting from the book - Computing Essential 2011