Technology Component: Computer Hardware – Part 2 Basic Components Dr. V.T. Raja Oregon State University

Basic Components of Hardware Input Devices Processor/Central Processor/Chip –CPU/ALU –Primary Storage Secondary Storage Output Devices Communication Devices (to be discussed later in another chapter)

Processor Processor (Chip) has CPU and Primary Memory CPU does all the processing work in a computer Primary memory stores data and instructions Instruction: A command that tells a computer how to accomplish a given task CPU has Arithmetic Logic Unit (ALU) and Control Unit Control Unit accesses data and instructions from Primary Memory, and transfers them to ALU ALU performs basic arithmetic and logical operations

Types of Primary Memory: ROM and RAM ROM –PROM –EPROM RAM –SIMM –DIMM –SDRAM –RDRAM ROM stores some basic instructions permanently ROM is non-volatile RAM acts as a temporary storage for data and instructions RAM is volatile RAM size commonly expressed in MB or GB e.g,. 256 MB RAM; 2 GB RAM

Types of Primary Memory: Cache Memory Cache memory is a temporary storage for frequently used information CPU searches cache memory for data and instructions before it searches RAM Cache is typically located closer to CPU than RAM Bigger the cache, the faster the computer will perform (assuming all other factors are constant) Cache is volatile

Terminology What is clock speed? –Speed at which the processor completes machine cycles –Measured in Megahertz (MHz) or Gigahertz (GHz) Mega: Million; Giga: Billion –Hence, terminologies such as Pentium 4 / 3.2 GHz What is word length? –Number of bits that the processor processes at one time. –Example: 16-bit, 32-bit, 64-bit chips

Terminology What is data bus width? –The number of bits that can be moved at one time between the CPU, primary memory and other devices of a computer. Which would you select? A 16-bit chip with a 16-bit data bus width (or) a 32-bit chip with a 8-bit data bus width? Factors affecting speed of a computer are: –Clock Speed –Word Length –Bus Width

Input Devices Examples of input devices? What is Source Data Automation (SDA)? Examples of SDA? What are some advantages associated with SDA?

Storage Devices Examples of secondary storage? Typical storage capacity of secondary storage devices