Hardware Basics: Inside The Box Chapter 2
Bits, Bytes, and Buzzwords
Thomas J. Watson, Sr. Created a culture of invention
IBM remains an industry leader and innovator
What Computers Do Receive Input Process Information Produce Output
What Computers Do Store Information
Input Devices The keyboard is the most common input device
Pointing devices like the mouse also receive input
Output Devices Computers produce information and send it to the outside world. A video monitor is a common output device.
Printers also produce output.
Process Information The processor, or central processing unit (CPU), processes information and performs all the necessary arithmetic calculations.
The CPU is like the “brain” of the computer.
Store Information Memory and storage devices are used to store information Primary storage is the computer’s main memory
Secondary storage uses disks or other media
Information Information comes in many forms Text 1 2 3 Numbers Sounds Pictures
Computers store information in digital form
Bit Basics is the smallest unit of information can have two values: 1 or 0 On
can represent numbers , codes , or instructions
Bits as Numbers Each switch can be used to store a tiny amount of information, such as: An answer to a yes/no question A signal to turn on a light Larger chunks of information are stored by grouping bits as units
8 bits (byte) = 256 different messages
Bits As Codes ASCII – American Standard Code for Information Interchange
Most widely used code, represents each character as a unique 8-bit code.
Bits as Instruction The computer stores instructions as collections of bits. For instance, 01101010 might instruct the computer to add two numbers.
Other bit instructions might include where to find numbers stored in memory or where to store them.
Bits, Bytes, and Buzzwords
Terms used to describe file size or memory size:
The CPU and Memory The microprocessor that makes up your personal computer’s central processing unit , or CPU, is the ultimate computer brain , messenger , ringmaster and boss . All the other components—RAM, disk drives, the monitor— exist only to bridge the gap between you and the processor. Ron White, in How Computers Work
The CPU interprets and executes instructions performs arithmetic and logical data manipulations
communicates with the other parts of the computer system.
The CPU The CPU is a complex collection of electronic circuits. When all of those circuits are built into a single silicon chip, the chip is referred to as a microprocessor .
The circuit board that contains a computer’s CPU is called the motherboard or system board .
Compatibility & Speed Compatibility Speed
When purchasing a computer, selecting a CPU is very important. The two most critical factors are:
Compatibility Software is written for a specific processor and may not be compatible with another CPU. Every processor has a built-in instruction set or vocabulary of instructions that only the processor can execute.
CPUs in the same family are generally designed to be backward compatible so newer processors can process all of the instructions handled by earlier models.
Speed A computer’s speed is determined in part by the speed of its internal clock The clock is a timing device that produces electrical pulses to synchronize the computer’s operations.
A computer’s clock speed is measured in units called megahertz (MHz) , for millions of clock cycles per second
Speed Clock speed by itself doesn’t adequately describe how fast a computer can process words, numbers, or pictures.
Speed is also limited by architecture and word size.
Speed Parallel processing places multiple processors in a computer.
Most supercomputers have multiple processors that divide jobs into pieces and work in parallel on the pieces.
The Computer’s Memory RAM (random access memory): is used to store program instructions and data temporarily unique addresses and data can be stored in any location can quickly retrieve information
will not remain if power goes off (volatile )
The Computer’s Memory information is stored permanently on a chip.
contains startup instructions and other permanent data.
Buses, Ports, and Peripherals Buses connect to storage devices in open areas in the box called bays.
Information travels between components through groups of wires called buses .
Buses, Ports, and Peripherals Busses also connect to slots inside the computer
Sockets on the outside of the computer called ports .
Buses, Ports, and Peripherals Slots and ports also allow external devices called peripherals to be added to the system (keyboard, monitor, and mouse).
Without peripherals , the CPU and memory are like a brain without a body.