a) Personal computers (PC) are developed from the 8-bits Apple in 1976 to the 16-bits PC/AT/XT in the 80¡¦s, then to the 32-bits 386/486/586/Pentium today.
b) In the past, MS-DOS, a 16-bits operating system (OS), dominates the OS for PCs. For those 32-bits computers i.e. 386/486/586/Pentium, processing speed are reduced because of under-utilize of the other 16-bits.
c) Besides slow in processing speed, the usable memory of DOS is limited to 640K. This cause computer hangs up easily as programs compete themselves for memory.
d) As DOS is a command driven interface, users have to remember and type in a lot of long and clumsy commands before the computers can work.
e) To resolve the shortcoming of DOS, Microsoft launched Windows 3.0 in 1990. Besides breaking the 640K memory limited, it also provided a Graphical User Interface (GUI) and multitasking environment to the users. Mouse is used to operate the OS instead of memorizing commands. Colorful icons and windows screens greatly enhanced the ease of use of the OS.
f) However, Windows 3.X is still work on top of DOS, i.e. DOS is needed to boot up computer before using Windows 3.X. Therefore, strictly speaking, Windows 3.X is an operating environment instead of an operating system. In addition, Windows 3.X is 16-bits OS that is not the perfect match with those 32-bits computers.
g) Windows 95 was launched in 1995 with the following benefits:
Ü True operating system: it no longer needs DOS to boot up the computer.
Ü 32-bits OS: processing speed is much improved with 32-bits computer.
Ü More stable working environment: the memory of each program is separated. If one program is hanged, others programs will not be affected.
Ü More friendly user interface: the use of ¡§Start Button¡¨, ¡§Task Bar¡¨ and ¡§Program Shortcut¡¨ greatly enhance the ease of use.
Ü Plug and Play: different hardware drivers are installed automatically.
Ü Network and Communication: by using telephone