What are MicroProcessor architectures?

The ENIAC (Electronic Numerical Integrator and Computer) was the first general purpose computer. It was invented in late 1945 and became operational by early 1946. It was invented during the Second World War by two engineers John Presper Eckert and John W. Mauchly, at the University of Pennsylvania. The ENIAC though being the first general purpose computer was not used widely due to the its huge mass. It occupied almost 1800 sq ft i.e., almost half a basketball court and weighed 30 tons. The ENIAC did not contain any typical processor. It was made of 17,468 vacuum tubes in 40 panels along with wiring, switches and so on. It could add 5000 numbers per second. Each panel used to perform some different functions.

What is a Vacuum tube?

Now, the term vacuum tube must not be familiar with many of you, as it is not used in making computers anymore. It is a bulb like structure with a glass cover outside and cathode, anode, grids and vacuum inside. One vacuum tube means one bit, that means if current flowed through it, it was on else off(i.e., 1 and 0 respectively). It was also known as thermionic valve as it was used to control the electrical signals by releasing electrons from the cathode in the vacuum by thermionic emission. The size of a vacuum tube varied from 1 inch to 6 inches in size which is almost the size of a 15 cm scale.

What is a bit?

One bit means one on and off(i.e., one 1 and 0). The more number of bits, the more faster is a task is performed by the computer. The ENIAC had a system of 17,468 bits, as one vacuum tube is equivalent to one bit. It is the number of information a computer can process i.e., a single vacuum tube can process 1bit of data only. This means that ENIAC was too slow or rather all computers based on vacuum tubes were slow.

Why are Vacuum tubes used no more?

The invention of transistors was the revolution in the field of computing and electronics. Electronic goods made of vacuum tubes were too large in size due to the size of one vacuum tube, whereas the microprocessors made up of the transistors are of the same size as one vacuum tube which contained the entire system of ENIAC in just one chip of 12 sq mm. The first microprocessor was made by Intel i.e., Intel 4004 with a size of 12 sq mm. The computers made of vacuum tubes were program controlled(i.e., they were CUI based computers) to perform a calculation which often took weeks (to program them). However, the computers based on modern microprocessors on the other hand are quite easy to control because most of them are GUI based. The computers based on modern microprocessors are quite fast which process data at 2^n (where n is the number of bits). This means that a Intel 4004(first microprocessor), a system of 4 bits can process a data 2^4=4KB of data, whereas the computers processed based on the number of vacuum tubes present in them. Vacuum tubes consumed more power, they were fragile and required frequent replacement which also was expensive, but the microprocessors consume less power, they are quite sturdy also cheaper.

What are microprocessor architectures?

Now we come to the main topic i.e., what processor architectures are. So, in early 1940s and 1950 after the invention of transistors the size of the computers became quite small as the work done by thousands of Vacuum tubes could be done only by a 12 sq mm chip rather more can be done by that. The first microprocessor Intel 4004 was invented in1971 by Intel Corporation, specifically designed by Federico Faggin, along with Marcian Hoff, Masatoshi Shima and Stanley Mazor. Now a typical processor like Intel Core i5 or i7, contain a number of components fitted inside them like threads, cores, graphics, ALU, etc. but the microprocessor is quite smaller than that. The architectures of processors are just like the plan of a house. As in the plan of a house we decide what will be the size of the kitchen or where the car will be parked, similarly in a microprocessor architecture we decide what type of transistors, how many transistors or where will be the ALU(Arithmetic Logical Unit) placed and so on.

You may have noticed while installing applications they ask if your computer is running a 32 bit OS or a 64 bit OS but what is it? So, after Intel 4004 there were many architectures invented like Intel 8008 or Intel 8080(8-bit microprocessor), Intel 8086(16-bit microprocessor) Intel 80386(32-bit microprocssor) and so on.

Now Intel 8086 architecture laid the foundation of the x86(16-bit microprocessors to 64-bit microprocessors) family of microprocessor architecture. These architectures decide how fast a data will be processed in a microprocessor(can be determined by 2^n formula mentioned earlier). The modern microprocessors use the same architecture as Intel 8086. It’s like doing the same work with different number of workers i.e., as the number of workers increases the faster you can complete the work. Similarly, if the no. of bits increase the faster you can work. The new architectures work with the x86 architecture along with a 64 bit extension(x86-64 architecture) and hence the modern 64 bit processors can process 16 EB data which is more than enough. There are many other architectures like x86(Intel and AMD processors), ARM(Qualcomm processors), MIPS(Apple processors).