CENTRAL PROCCESSING UNIT PRESENTED BY DEAN CASEY

CENTRAL PROCESING UNIT The central processing unit (cpu) known as the processor. It is an electronic circuit that can execute computer commands. Even though the (cpu) has changed in form and design since the earliest computers their fundamental operation has remained the same.

HISTORY OF CENTRAL PROCCESSING UNIT The early central processing unit were custom designed to run a specific program in computers called ENIAC. These had to be manually rewired to enable them to perform tasks and became known as fixed program computers. The EDVAC computers were designed to perform multiple tasks and programs were able to be stored in the computer memory instead of having to manually rewire it.

DESCRETE TRANSISTOR & INTERGRATED CIRCUIT The design of the central processing unit became more complex as they started to build smaller and more reliable electronic devices. The first improvements came by the creation of the Transistor, which allowed the central processing units to be built onto one or more printed circuit boards which contained discrete individual components. The integrated circuit also known as I.C. contained a large number of transistors and was manufactured on a single semiconductor based die or chip.

MICROPROCESSORS The microprocessors introduced in 1970 changed the design and implementation of the central processing unit (cpu). The first microprocessor was the Intel 404 and the first widely used microprocessor was the Intel 8080 in The microprocessors central processing unit are manufactured on a small number of integrated circuits but usually produced on one integrated circuit on one die.

CENTRAL PROCCESSING UNIT OPERATION The operation of the CPU stays the same no matter what the size. Most CPU’s follow these steps fetch, decode,execute and write back. Fetch; retrieves instructions from program memory. The location of the memory is determined by the program counter which identifies the current position in the program. The instruction that the CPU obtains decides what the CPU will do. Decode; the instructions are broken up into parts by the CPU Instruction set where one group of numbers indicate which operation to perform and the other group of numbers provide information required for that operation. Execute; various portions of the CPU are connected so that they can perform the desired operation. Write back ;writes back the results of the execute step to memory.

Summary There is a lot of information on central processing units. History, design, complexity and how they have changed from the 1960’s to the 21 century. Central processing units will continue to change in their design and complexity as technology is always becoming more advanced.

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