basic of computer or PC

Definition of a Computer -A machine that given instructions and can manipulate data by itself.

Basic Computer Needs
-Need to perform calculations faster and more accurately.
-Need to control processes consistently.
-Need to handle larger and larger amounts of data

Computer System-A computer system contains two parts:
-Hardware: actual pieces of equipment-keyboards, screens, components inside the boxes, printers, modems, etc.
-Software: instructions that direct-operating systems, compilers, applications

Hardware
-Access to data
-Read: fetching information from somewhere
-Write: putting information somewhere
-Common hardware components
-Central Processing Unit(CPU)
-Main Memory
-Secondary Storage
-Input & Output(I/O)

software operating system:
window:
(window history :
1985: Windows 1.0
1987: Windows 2.0
1990: Windows 3.0
1993: Windows NT 3.1
1993: Windows for Workgroups 3.11
1994: Windows NT Workstation 3.5
1995: Windows 95
1996: Windows NT Workstation 4.0
1998: Windows 98
1999: Windows 98 Second Edition
2000: Windows Millennium Edition (Windows Me)
2000: Windows 2000 Professional
2001: Windows XP
2001: Windows XP Professional
2001: Windows XP Home Edition
2001: Windows XP 64-bit Edition
2002: Windows XP Media Center Edition
2002: Windows XP Tablet PC Edition
2007: Window vista basic, home premium, business, ultimate)
LINUX
UNIX
MAC


CPU
-CPU is the heart of any computer-
Three functions
1. control: CPU takes on instruction at a time and follows it to direct the rest of the system.
2. arithmetic operations: addition, subtraction, multiplication, division.
3. logical operation: comparisons

Main Memory
-Main memory is a temporary, working storage area.
-Stores two types of things:
1. current set of instructions the CPU is following.
2. data these instructions manipulate.
-Made up locations with unique addresses.
-Addresses allow random access of data.
-Very fast, but expensive and volatile.

Secondary Storage
-Permanent storage device-Disk, hard and floppy, are common examples
-Relatively cheap, but slow(can be hundreds of times slower than Main Memory)
-Accessed in blocks(many characters at a time)

I/O Devices
-Provide a way for humans to communicate with computers
-Common input devices:
1. Keyboard
2. Mouse
3. Scanner
-Common output devices:
1. Monitor
2. Printer
3. Speaker