Lecture 1 Computer Organization Review v.3 PDF

AN INTRODUCTION COMPUTER SYSTEM BLOCK DIAGRAM Next VON NUEMANN ARCHITECTURE VON NUEMANN ARCHITECTURE Bus Electrical pathway used to move data between components Local bus: Connects the CPU with the memory Expansion bus...

AN INTRODUCTION COMPUTER SYSTEM BLOCK DIAGRAM Next VON NUEMANN ARCHITECTURE VON NUEMANN ARCHITECTURE Bus Electrical pathway used to move data between components Local bus: Connects the CPU with the memory Expansion bus: Connects the CPU with peripheral devices VON NUEMANN ARCHITECTURE Bus clock speed Rate of speed data moves from one location to another Measured in Mhz (millions of clock cycles per second) Bus width The number of bits of data moved on a bus at any one time Measured in bits 16 bits 32 bits The System Unit What is the system unit? Case that contains electronic components of the computer used to process data ▪ Sometimes called the chassis The System Unit What are common components inside the system unit? power supply drive bays Processor Memory processor Adapter cards ▪ Sound card ports memory ▪ Video card Ports Drive bays Power supply sound card video card The System Unit What is the motherboard? Main circuit board in system unit Contains adapter cards, processor chips, and memory chips Also called system board The System Unit A microchip connected directly to the CPU and thus responsible for tasks that require the highest performance. Southbridge is a reference to a chipset on a PC motherboard. This chipset controls or manages input and output (I/O). The System Unit What is a chip? Small piece of semi-conducting material on which integrated circuits are etched ▪ Integrated circuits contain many microscopic pathways capable of carrying electrical current Chips are packaged so they can be attached to a circuit board Processor What is the central processing unit (CPU)? Interprets and carries Processor out basic instructions Control Control Arithmetic Arithmetic Unit Logic Unit (ALU) (ALU) that operate a computer Unit Logic Unit ▪ Control unit directs and Instructions coordinates operations in Data computer Information ▪ Arithmetic logic unit (ALU) performs Input Output Devices Data Memory Information Devices arithmetic, comparison, and logical operations Instructions Also called the processor Data Information Storage Devices Processor Processor What is a register? Temporary high-speed storage area that holds data and instructions Stores location from where instruction was fetched Stores Stores data instruction while it is while ALU being decoded computes it Stores results of calculation Processor What is a machine cycle? Four operations of the CPU comprise a machine cycle Step 1. Fetch Obtain program instruction or data item from memory Memory Step 2. Step 4. Store Decode Write result to memory Translate instruction into Processor commands ALU Control Unit Step 3. Execute Carry out command Processor What is pipelining? CPU begins fetching second instruction before completing machine cycle for first instruction Results in faster processing Processor What is the system clock? Controls timing of all computer operations Generates regular electronic pulses, or ticks, that set operating pace of components of system unit Pace of system clock is clock speed Processor speed can Each tick Most clock speeds are also be measured in is a in the gigahertz (GHz) millions of instructions clock cycle range (1 GHz = one per second (MIPS) billion ticks of system clock per second) Processor Which processor should you select? The faster the processor, the more expensive the computer Intel Processor Desired Clock Speed Itanium or Xeon 1.3 GHz and up 3.0 GHz and up Pentium family 2.4 GHz to 3.0 GHz Up to 2.4 GHz Celeron 2.2 GHz and up Processor What are heat sinks, heat pipes, and liquid cooling? Heat sink—component with fins that cools processor Heat pipe —smaller e device for notebook computers Liquid cooling—uses a continuous flow of fluids to transfer heat away Processor What is parallel processing? Using multiple Control Processor processors simultaneously to execute a program faster Processor 1 Processor 2 Processor 3 Processor 4 Requires special Memory Memory Memory Memory software to divide problem and bring results together Results combined Data Representation How do computers represent data? Most computers are digital ▪ Recognize only two discrete states: on or off ▪ Use a binary system to recognize two states ▪ Use Number system with two unique digits: 0 and 1, called bits (short for binary digits) Data Representation What is a byte? Eight bits grouped together as a unit Provides enough different combinations of 0s and 1s to represent 256 individual characters ▪ Numbers ▪ Uppercase and lowercase letters ▪ Punctuation marks ▪ Other Data Representation What are three popular coding systems to represent data? ASCII—American Standard Code for Information Interchange EBCDIC—Extended Binary Coded Decimal Interchange Code Unicode—coding scheme capable of representing all world’s languages ASCII Symbol EBCDIC 00110000 0 11110000 00110001 1 11110001 00110010 2 11110010 00110011 3 11110011 Data Representation How is a letter converted to binary form and back? Step 1. The user presses Step 2. the capital letter T An electronic signal for the (shift+T key) on capital letter T is sent to the the keyboard. system unit. T Step 4. Step 3. After processing, the binary The signal for the capital letter T code for the capital letter T is is converted to its ASCII binary converted to an image, and code (01010100) and is stored in displayed on the output device. memory for processing.