Microprocessor

Every computer system has a unit whose primary purpose is to process data.This unit is the control center of the entire computer system.It accepts data from input devices,processes data,and sends results to the printer or other output devices under control of a stored program.This unit is referred to as the microprocessor in a microcomputer and the central processing unit(CPU) in large computer systems.Both units perform basically the same functions.

Computer Crime

• Software Piracy
• Protections from Piracy 

Software Piracy: 

• Software piracy – the illegal copying of software programs – is the biggest legal issue affecting the computer industry.
• Piracy is of greatest concern to developers of commercial software, or programs that must be purchased before using.
• Piracy is less of a concern for shareware makers, whose programs must be registered but not always purchased. 
• Piracy is not a concern for freeware, which is software that can be freely distributed by anyone.

Protections from Piracy: 

Various forms of copy protection have been used to discourage piracy, including:

•  Installation diskettes that record the number of times the software is installed.
• Hardware locks, without which the program cannot function.
• Passwords, serial numbers, or other codes required for installation.

Small History of Windows-OS

Windows 3.x :

• Windows 3.0, 3.1, and 3.11 are called the Windows 3.x family.
• Windows 3.x brought a GUI and multitasking capabilities to PCs running DOS.
• Windows 3.x is an operating environment because it ran on top of DOS, which was the actual OS.

Windows NT: 

• To work on most PCs at the time of its release.
• Microsoft issued two versions of Windows NT—Windows NT Workstation and Windows NT Server. Microsoft's Windows NT was meant as a replacement for DOS, but was too resource-intensive.
• NT is a very powerful and robust OS, resistant to system crashes. 

Windows 95 and 98: 

• An improved user interface, and enhanced file system performance, among others. Windows 95 was Microsoft's first true GUI-based, 32-bit operating system for Intel PCs.
• Windows 95 supports multitasking and can run older DOS and Windows 3.x programs.
• Windows 98's  features include advanced Internet capabilities.

Windows 2000: 

• Windows 2000 features the same interface and features of Windows 98, with the file system, networking, power, and stability of Windows NT.
• Several versions of Windows 2000 are available, each targeting a specific user or computing environment, from home PCs to large enterprise networks. 

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Smart OS-Linux

• Linux is a recently developed version of UNIX, which is available for free or at a very low cost from various sources.
• Linux is a very powerful 32-bit OS that supports multitasking, multiple users, networking, and virtually any application.
• Linux can run on nearly any type of computer.
• Because of its power and openness, Linux is attracting many users, including students, teachers, Internet service providers, and others.
  

Factors Affecting Processing Speed

• Registers
• RAM
• The System Clock, 
• The Bus
• Cache Memory

Registers: 

• The CPU contains of small memory areas:called registers,which store data and instructions while the CPU processes them.
• The size of the registers determines the amount of data with which the computer can work at a one time.
• Today most PC`s have 32-bit registers,mean the CPU can process four bytes data at one time.Register sizes are rapidly growing to 64 bits.

RAM: 

• The amount of RAM in a PC has a direct affect on the system`s speed.
• The more RAM a PC has.the more program instructions and data can be held in memory,which is faster than storage on disk.
• If a PC does not have enough memory to run a program,it must move data between RAM and the hard disk frequently.This process called swapping,can greatly slow a PC`s performance. 

                                        More RAM=Better Performance!  

The System Clock: 

• The computer`s system clock sets the pace the CPU by using a vibrating quartz crystal.
• A single "tick" of the clock is the time required to turn a transistor off and back on.This is called a clock cycle.
• Clock cycles are measured in Hertz(Hz),a measure of cycles per second.If a computer has a clock speed of 300 MHz, then its system clock"ticks" 300 million times every seconds.
• The faster a PCs clock runs,the more instructions the PC can execute each second. 

The Bus: 

• A bus is a path between the components of a computer.Data and instructions travel along these paths.
• The data bus width determines how many bits can be transmitted between the CPU and other devices.
• The address buss runs only between the CPU and RAM, and carries nothing but memory addresses for the CPU to use.
• Peripheral devices are connected to the CPU by an expansion bus. 

Cache Memory: 

• Cache memory is high-speed memory that holds the most recent data and instructions that have been loaded by the CPU.
• Cache is located directly on the CPU or between the CPU and RAM,making it faster than normal RAM.
• CPU-resident cache is called Level-1 (L1)cache.External cache is called Level-2(L2) cache.
• The amount of cache memory has a tremendous impact on the computer`s speed.

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