Chapter 4 Data Processing

Chapter 4 Data Processing

Lecture 311/3/2011All Rights Reserved1 Introduction To computers Chapter OutlineTransforming data into informationHow computers represent dataHow computers process dataFactors affecting processor speed11/3/2011All Rights Reserved2 Introduction To computers Volatile MemoryNeeds power to store data.People usually mean RAM whey talking about computers memory.Physically RAM consists of chips on small circuit board.Two types of RAM are found in personal computers. Single inline memory modules(SIMM) andDouble inline memory modules(DIMM) SO-DIMM (small outline DIMM) is for laptop computers.

11/3/2011All Rights Reserved3 Introduction To computers ContdThe random in RAM means any portion in RAM can be accessed at any time.If it the access method would be sequential, the computer would be very slow.CPU uses memory address to store and retrieve each piece of data.memory address is a number that indicates location on the memory chips.RAM is not only used by computers CPU but components such as video and sound cards as well.

11/3/2011All Rights Reserved4 Introduction To computers

Factors affecting processor speed

Apart from Memory and registers, there are other components that affect the processors speed.Cache memory, clock speed and the data bus affect the processors speed.RegistersRegisters are normally measured by the number of bits they can hold, for example, an "8-bit register" or a "32-bit register or even 64-bit register The size of the registers which is sometimes called the word size indicates the amount of data with which the computer can process at any given time.

11/3/2011All Rights Reserved5 Introduction To computers

Factors affecting processor speed

The bigger the word size, the more quickly the computer can process a set of data.People often refer to 32-bit processors or 64-bit processors or even 64-bit computers this terminology refers to the size of the registers in the processor.With all other factors kept equal, a CPU with 32-bit registers can process twice as fast as one with 16-bit registers.11/3/2011All Rights Reserved6 Introduction To computers Memory and computing powerThe amount of memory(RAM) in a computer can have a profound impact on a computers power.The bigger the size of RAM in a computer, the more the computer can run faster.The computer doesnt necessarily have to load an entire program into memory to run it however the greater the amount of the program that fits into memory, the faster the program runs.To run windows for example, the computer usually doesnt need to load all its files into memory to run properly.Only the most essential parts come into memory.11/3/2011All Rights Reserved7 Introduction To computers ContdIf the processor needs to access other parts of OS or a program on the disk, it can unload or swap out none essential parts from RAM to hard disk. Then the computer can load or swap in the program code it needs.Although this is an effective method for managing a limited amount of memory, the computers system performance is slower.Because the swapping process occupies the CPU, memory and hard disk.Swapping unused contents of RAM to the hard disk is known as Virtual Memory11/3/2011All Rights Reserved8 Introduction To computers