The Background Of Computers

Published Date: 02 Nov 2017

Introduction

Computer, an electrical device the human used in daily life in the advanced technologically era. It provided a lot of convenient to the user, which are allow user online via the internet service and allow user store data in the computer. A computer is built by several components such as ram, motherboard and monitors. One of the important components of computer is CPU. CPU stands for Central Processing Unit or we called Central Processor Unit. It is a hardware component within a computer.

The size of CPU same as a normal matchbox, although it was smaller than other component within a computer, but it was a core of the computer, because all operations are controlled by the CPU and it responsible for reading instruction, decode and execute instructions.

History

In the early years, the design of the CPU was custom designed for a specific computer, which at the time were massive machines that took up entire room of space. The earliest computer even required physical re-wirings of the computer’s interiors to adjust calculations………..

First Generation

Until November 1970, the first generation of single chips CPU was invented by Intel Company, the 4004. Intel 4004 was the first CPU used in a computer and the price of it was affordable to the user. 4004 was a 4-bit CPU and it contains 2300 transistor. The function of 4004 was limited and the speed of it is only 108 KHz (kilohertz) or 0.74 MHz (Megaherts). Since the function of 4004 was limited to the user, so Intel was invented the successor of 4004 which are Intel 8008.

Intel 8008 was launched on 1972; it was the first 8 bits processor that had 16kb of memory with 3500 transistor. The speed of 8008 was divided in 2 types, which are 0.5MHz and the upgraded version 0.8mMHz.Although the speed of 4004 was faster than 8008, but the overall feature of 8008 was better than 4004. Intel 8080 was another 8 bits CPU launched in 1974, but the speed of 8080 was increased to 2MHz, and it contains 6000 transistor and provided 8 bits data bus and 16 bits address bus in order allow easily access 64kb of memory.

Second Generation

In 1978, Intel created a 16 bits processor. It contains 29000 transistors and provided 16bit data bus and 20 address bus. And the memory of 8086 was increased to 1Mb, it was quite big at that time and the speed of 8086 was 8MHz. Although the programming model and instruction set was based on the design of 8080, but there are new kinds of instruction were added such as full support for signed integers, base+offset addressing, and self-repeating operations were akin to the Z80design but were all made slightly more general in the 8086. Instructions directly supporting nested ALGOL-family languages such as Pascal and PL/M were also added.

Intel 80286 as also called iAPX 286 or i286 was 1 of the series of X86. I286 was widely used in 1980s. It was a 16 bits CPU with 13thousand of transistors and it provided 16bits data bus and 24 address bus. After the 6 and 8MHz initial releases, the speed of i286 was increased to 25MHz. Compared to Intel 8086, i286 can address memory up to 16MB and supports virtual memory to emulate memory space, i286 also supports multi-threading by fast switching between the threads, so Intel 80286's performance was more than 5 times of i8086.

Intel 802086 was the first processor with protected mode and real mode. The real-mode feature is a section of a 20-bit memory address space (meaning only 1 MB of memory can be addressed), can direct software access to BIOS routines and peripheral hardware, no hardware level memory body protection concepts or more workers. 80286 series and after are based on the real-mode x86 CPU boot; 80186 and early CPU is only one mode of operation, which is equivalent to real mode chip later. Protected mode was another mode designed to enhance multi-tasking and system stability, such as memory protection, paging systems, and hardware support for virtual memory

Third Generation

In 1985, there are another new processor was created by Intel, the Intel 80386 or also called i386. There were several version of i386, which are DX, SX and SL. DX was the new invent of processor, it is the first ever 32 bits processor for personal computer in the world and it contains 275 thousand of transistors and 132pins to transfer data from processor to the motherboard. The speed of the i386DX processor was 12MHz. Late releases, by Intel and other companies, pushed the maximum speed of the processor to33 MHz. There are a new modes added in to i386DX, which are virtual 8086 mode. This mode allowed processor to run 1 or more real mode program, but some time there are some programs were not compatible. In addition, the i386DX can address 4 GB of memory and also can manage 64tb of virtual memory.

Intel 80386SX was introduced as a low cost version of i386, it only has 100 pins to transfer data from processor to motherboard, and it has 16 bit data bus and 24 bit of address bus. The speed of i386sx was 16MHz to 33MHz. Intel 80386 SL was a mobile version of the i386DX, it was specified designed for the laptop. It had 16 bit data bus and 24 bit address bus. The speed of i386SL was 25MHz. I386SL requires the less power compare to the DX and SL and it had the sleep modes to conserve the power.

In 1989, Intel created another 32 bit processor, the i80468. It contains 1.2 million transistors and provided 32 bit of address bus and data buss. The feature of I 38486 was similar to the i80386DX. Compare to each other, the speed of i80486 was increased to 50MHz, so it can executed 40 million instructions per second on average and was able to reach 50 MIPS peak performance, and there were added few new instruction set in i80486 too.

Fourth Generation

In 1993, Intel introduced a new series of processor Pentium. The Pentium was contains 3.21million of transistors and it provided 32 bit address bus and 64 bit data bus. The speed of Pentium was twice of the 80468. Pentium Pro, the successor of Pentium. It followed in 1995. It contained 5.5 ,million transistor and the speed was 550MHz. Pentium Pro has an 8 KB instruction cache, from which up to 16 bytes are fetched on each cycle and sent to the instruction decoders.

The design of Pentium Pro was optimized for 32-bit code; when running 16-bit code it worked no faster than the original Pentium system. The Pentium II arrived in 1997, with a 32 KB L1 cache and 512 KB of L2 cache. In 1999 the Pentium III was released, which operates at 450 MHz with a 100MHz bus, and SSE. In 2000, the Pentium IV made its debut. Pentium 4 contained 42 million transistors and the speed of it was 3.06GHz.

Fifth Generation

Core, another new series introduced by Intel in 2006. The first product of Core series was Core 2 Duo. Core 2 Duo was the first dual-core-processor in the world; it contained 820 million transistor and provided 64 bit data and address bus. Dual core processor allowed different programs to use separate processing cores, offering better efficiency and faster clock speeds.

The most significant change is to be strengthened in various critical portions. In order to improve the internal efficiency of data exchange in two cores take shared secondary cache design, two cores shared up to 4MB of L2 cache.

In 2008, Intel launched the first 64 bit processor in the world, the Core i7. Core i7 Follow the x86-64 instruction set, based on Intel Nehalem microarchitecture to replace the Intel Core 2 series processors. Intel Core i7 processor is not just the most amazing processor of Intel, more imported is it added intelligent processing functions, it allows the processor automatically when performance is needed to improve processor performance and reduce power consumption when it is not needed amount. The Core i7 contained 731 million of transistors and provided 3.40GHz operating frequency.

Core i5 was the another product of Intel under the Core series, it launched by Intel on 2009. Core i5 provided L2 buffer memory, each core has separate 256KB, and shared up to 8MB of L3 cache memory. Besides that, Core i5 also Support SLI and Crossfire technology. In 2010, Intel launched Core i3 processor; it was Clarkdale-based, with an integrated GPU and two cores. The same processor is also available as Core i5 and Pentium, with slightly different configurations. Core i3 provided L3 buffer memory and two cores sharing 4MB.

Conclusion

a

Within a computer, all of the hardware is communicate to each other by using the bus. A bus is a communication pathway connecting 1 or more devices. A key characteristic of a bus is that it is a shared transmission medium.

Interconnection

The data lines provide a path for moving data between system modules. These lines, collectively, are called the data bus. The data bus may consist of from 32 to hundreds of separate lines, the number of lines being referred to as the width of the data bus. Because each line can carry only 1 bit at a time, the number of lines determines how many bits can be transferred at a time. The width of the data bus is a key factor in determining overall system performance. For example, if the data bus is 8 bits wide and each instruction is 16 bits long, then the processor must access the memory module twice during each instruction cycle.

The address lines are used to designate the source or destination of the data on the data bus. For example, if the processor wishes to read a word (8,16or 32 bits) of data from memory, it puts the address of the desired word on the address lines. Clearly, the width of the address bus determines the maximum possible memory capacity of the system. Furthermore, the address lines are generally also used to address I/O ports. Typically, the higher-order bits are used to select a particular module on the bus, and the lower-order bits select a memory location or I/O port within the module. For example, on an 8 bit address 01111111 and below might reference location in a memory module (module 0) with 128 word of memory, and address 10000000 and above refer to devices attached to an I/O module (module 1).

The control lines are used to control the access to and the use of the data and address lines. Because the data and address lines are shared by all components, there must be a means of controlling their use. Control signals transmit both command and timing information between system modules. Timing signals indicate the validity of data and address information. Command signal specify operations to be performed. Typical control lines include the following:

Memory write: Cause data on the bus to be written into the addressed location

Memory read: Cause data from the addressed location to be placed on the bus

I/O write: Cause data from the addressed location to be places on the bus

I/O read: Cause data from the addressed I/O port to be placed on the bus

Transfer ACK: Indicates that data have been accepted from or placed on the bus

Bus request: Indicates that a module needs to gain control of the bus.

Bus grant: Indicates that a requesting module has been granted control of the bus

Interrupt request: Indicates that an interrupt is pending

Interrupt ACK: Acknowledges that the pending interrupt has been recognized

Reset: Initializes all modules.