Processor decides the speed of the computer that it will execute the instruction fast or it will process slow. When a user thinks about to purchase a system the first question is in mind is processor. The first commercial microprocessor was the Intel 4004 launched in 1971, which was designed to be used in a Japanese desk calculator.
The processor is the heart of the computer. It is an integral part of the computer that controls all the working of the computer. Similarly, we said that CPU is the main part of the computer that controls the working of the computer. Don’t get confused in these two words processor and CPU. Both are used interchangeably.
Processors lie at the heart of all modern computers, not only personal computers, and are also EMBEDDED as controllers in many industrial and domestic appliances, from cars to washing machines. A single microprocessor chip, together with some memory chips, forms the basis for a simple computer (and for some embedded applications may even have the memory integrated onto the same chip). The electronic components of a modern microprocessor chip are very densely packed, cramming some 100 million transistors onto silicon die around 15 mm square, and this density rises with every generation (in accordance with MOORE'SLAW).
The Processor is a silicon chip assembled on the motherboard for performing calculation, execution instructions and controlling all peripheral devices. Microprocessor takes input from input devices convert into machine language, a transfer instruction to the instruction register and data content to data register or accumulator for processing, after the execution of the instruction the output is visible on the monitor in human-readable form. Microprocessors having two units one is ALU and second is control unit. ALU performs all mathematical operation addition, subtraction, multiplication, division, a logical operation like or, not, and Control unit control the devices by executing control signals.
The main components of a typical microprocessor chip are: integer and floating point arithmetic units which actually perform the calculations; a bank of registers that hold both the numbers currently being worked on, and the results; an instruction fetch unit which gets tile next instructions to be executed from external memory; one or more caches to speed up access to data and instructions that are anticipated to be needed soon; and a control unit which choreographs the operations of all these other units. Together, these core units act as the central processing unit (CPU) of a computer. Mainstream microprocessors, such as those of the Intel Pentium or the power pc families, often integrate several additional functional units such as a memory management unit; interrupt controller and bus control unit onto the chip. There is also a tendency toward adding special units and instructions to assist specific tasks such as graphics or sound processing.
Formation of CPU chip
A computer integrated onto a single piece of silicon or CHIP, often referred to informally as a microchip, or the silicon chip. Silicon is semiconducting metal. Microchips are made from silicon sand. Silicon wafers are produced from the purified silicon melt. Many Silicon wafers are packed in sealed containers to convert into in microprocessor.These wafers have 3-dimensional layers. Silicon wafer has latex to fit the transistor in it. ‘Photolithographic printing process is used to embed transistors into the wafer. Now the typical work to link up the finest interconnects wire with a tiny transistor and convert into an integrated circuit. Before performing this task cleaning of the wafer is most important so that wafer don’t have any dust particle on it. The barrier layer is used in chip formation so that short circuit problem will not rise, chips are reliable to use for a long time. After that copper is filed in blank space of wafer and extra copper get removed. In this way, all layers are connected to form a chip.
Before moving ahead some terms related to microprocessors like GHz, System clock, 32 bit or 64-bit operating system. Why do we use all these terms for system specification?
All these terms used to tell about the system’s instruction execution speed, its data capability how much bits data it can handle? For example Intel i3 CPU @ 2.40 GHz with 32 bit operating System. Means that 1 GHz means=1000000000= 1 billion. Microprocessors have 2.4 billion clock-pulses in one second. In each clock, pulse CPU has the opportunity to execute the instruction. But it is not necessary that each instruction gets executed in one clock pulse. It may require different -different clock pulse for execution.
32 bit or 64-bit operating system can handle 32 or 64-bit data during execution of one instruction. Basically, it shows the capacity of CPU to handle the data.
Types of Microprocessor or Processor
We have basically two categories of microprocessors listed below with a small description.
CISC (Complex Instruction set computing): CISC used complex and a long way to execute the instructions. CISC program is small in size because of complex addressing mode, instruction set as comparisons to RISC. Due to the complex instruction set, it takes more time to execute the command, hence speeds get down.
RISC (Reduced Instruction set computing): RISC multiprocessor used small instruction set, simple addressing mode to perform any instruction. So that Instruction will complete using few clock cycle and freed the acquire resources quickly.
The modern computer is based on Harvard Architecture. In this architecture, different buses are used for fetching data and instructions. But in Von Neumann architecture, a single bus is used for data and instruction flow. So that system cannot fetch instruction and data simultaneously. .But using Harvard architecture, we can fetch data and execute the instruction using both buses. We can fetch the instruction and data from different memory like cache or memory at the same time. Microprocessor used instruction set for data handling, memory operation, Arithmetic and logical operations, control flow or branch instructions. These instruction set further contains many instructions related to these groups.
History of Microprocessor: Microprocessor took a long time to change its configuration, capability, flexibility and it has been going to change day by day to make it small and provide more functionality through a single processor.
Vacuum Tube: On November 16, 1904, British engineer John Ambrose Fleming invents and patents the first vacuum tube. ENIAC was the first computer to use Vacuum tube. It occupies the whole room, generates a lot of heat. Vacuum tube function as a switch and amplifier in the computer.
Transistors: Transistors was invented by William Shockley, John Bardeen, and Walter Brattain at Bell Laboratories on December 16, 1947.It functions as a switch to allow or block the current. Due to the invention of transistor CPU size gets reduced. They consumed less electricity and produced less heat and faster and more efficient.
Starting with Intel Processors: Intel founded by Gordon Moore and Robert Noyce on July 18, 1968. The company bought the rights to use the name “Intel”, short name for integrated electronics.
4-bit processor: They invented a microprocessor chip Intel 4004, having transistors 2300, clock rate 740 KHz, Memory up to 4096 bytes.
8-bit processor: Intel 8080(1974) microprocessor is broken through for the computer industry. It was 10 times faster than Intel 8008(1972).
Clock rate =2 MHz
Feature size =6 Microns.
Intel 16 bit processor: Processors are 8086, 8088, 80186, 80286.
Intel 80286(1989) microprocessor contain
Clock rate =6 to 25 MHz
Memory=up to 16 MB
Feature size =1.5 Microns
Intel 32 bit processor: First time the concept of Cache was introduced in Intel 80486.
Transistors=11, 80,235, Clock rate =16 to 100 MHz, Memory=up to 4 GB,
Feature size =1 Microns, Cache size=8to 16 kb
With the passage of time, Intel modified its technology and invented Intel Pentium, Intel Pentium Pro, Intel Core processor, Intel i3, Intel i5 and Intel i7.
More processors working on different platforms are:
Clover town and Woodcrest are 64-bit processor->used for Server & workstation. They used 65 nm technologies.
Conroe (65-Technolgy): Used for Desktop Computing.
Merom (65-Technolgy): Used for mobile computing. It introduced on July 27, 2006.