Transcript How Computers Work

How Computers Work
All Computers
process data
• 1-- Input data
• 2--Store data while being processed
• 3--Process the data according to specific
instructions
• 4--Output the results in the form of new
data
All Computers Process Data According to
specific instructions -- Those instructions
are entered through INPUT DEVICES
• Mouse
• Keyboard
• Touch Screen
Scanner
Drives
Microphone
Camera
Peripheral
devices
All Computers have memory
RAM (Random
Access Memory
Storage -- Hard Drive
Video Memory
All Computers have a CPU
• The CPU is the Central Processing Unit
• It is the equivalent of the human brain for a
computer
• It processes data (input) and makes decisions
based on instructions in the programs
Computer Hardware
(a machine)
Software
(programs)
• Instructions that the computer needs to function
the way we want it to
The number of apps available for
download in leading app stores in July
2014. As of that month, Android users
were able to choose between 1.3 million
apps. Apple's App Store remained the
second-largest app store with 1.2 million
available apps.
Computer Memory
• ROM -- Read Only Memory. Memory
that is “burned” on the chip for basic
instructions for the computer to start
up.
• PERMANENT Part of the computer
that you normally don’t change factory
settings
RAM MEMORY
• RANDOM ACCESS MEMORY
• Temporary memory where data and
instructions are stored. Programs
require RAM to operate. When
machine is turned off, what is in RAM is
LOST. RAM is VERY Important when
purchasing a computer. Standards are
6-8 gb for laptops-desktops
CPU
Central Processing Unit
• It directs all the activities of the computer. It
follows the directions contained in ROM or
from a program that is operating in RAM
It adds numbers and compares numbers very very
quickly. The primary components are aluminum,
copper and (a hard plastic silicon)
Covered circuits are etched on the CPU
These circuits conduct electricity
Electrical circuits have one of 2 states ON or OFF
• 0 = OFF
• 1 = ON
Number system that uses only 2 numbers is called a
BINARY system. Adds and compares numbers
5X2 is 2+2+2+2+2+2
Letters are converted to binary code through ASCII
American Standard Code for Information
letter Binary
ASCII
• J 01001010
74
• I
01001001
73
• M 01001101
77
• Every 0 or 1 in the binary code is called BIT
(Binary Digit). These are grouped together by
the computer into 8 bit units called Bytes
• 1BYTE is 8 Binary digits
• 8 bit Units are called BYTES
Kilo – 1000 bytes
Mega – 1 million bytes
Giga – 1 billion bytes
Tera – 1 trillion bytes
1 Petabyte - 1 quadrillion
2007: 1 terabyte hard disk costs US$375
2010: 2 terabyte hard disk costs US$200
2012: 4 terabyte hard disk US$450 (Hitachi, largest available in
consumer market), 1 terabyte hard disk US$100
2013: 4 terabyte hard disk US$179, 3 terabyte hard disk $129, 2
terabyte hard disk $100, 1 terabyte hard disk US$80
2014: 4 terabyte hard disk US$150, 3 terabyte hard disk $129, 2
terabyte hard disk $90, 1 terabyte hard disk US$60