In last post we came to know about input and output devices of a computer.But every machine has input and output.What is then special in case of computer?
The computer processes the information as previously defined.It also stores the data input or output for future reference.Then lets know about the parts of the computer which make itspecial.
Storage devices are mainly classified into optical storage devices and magnetic storage devices. Also as solid-state devices (semiconductor).In magnetic storage data is stored by magnetizing a particular point on the medium due to application of magnetic field by means of electric field with the help of read/write magnetic head. The storage media is divided into several parts for easy accessing of data. The magnetic storage device is nothing but a disk coated with magnetic oxide. A hard disk is a set of aluminum disks coated with magnetic oxide. Due to its circular shape, the disks can be rotated to form a cylinder, the rotation also helps in storing and accessing the data randomly. The speed of rotation of magnetic disks describes the speed (RPM) and performance of a hard disk. The capacity of a hard disk is nothing but amount of data that can be stored in it. It depends on no. of platters (magnetic disks) and in each of the platter data is stored both on top and bottom of the disk. The data is erasable. It is best to choose a hard disk of required capacity.
Modern types of writable RAM generally store a bit of data in either the state of a flip-flop, as in SRAM (static RAM), or as a charge in a capacitor (or transistor gate), as in DRAM (dynamic RAM). RAM is of the read-only type, ROM, instead uses a metal mask to permanently enable/disable selected transistors, instead of storing a charge in them. Many computer systems have a memory hierarchy consisting of CPU registers, SRAM caches, external caches, DRAM, paging systems, and virtual memory or swap space on a hard drive. This entire memory is RAM. The data to be accessed every time a computer starts is recorded on hard disk with its addresses present in ROM.ROM memory is retained even if power is cutoff. Since RAM is vital for speedy access, more the ram better is the choice.
In optical storage devices data is stored in he form of humps and dumps i.e..data is read due to reflection of light by flat surfaces (humps) and scattering of light by pits (dumps).in these devices data storing is easier for first time.Ex: CD, DVD etc.due to rotation of the optical disk a sequence of 1s &0s are obtained which are converted into required information. The speed of an optical reading/writing device is defined in multiples of first device of a speed of 150KB/sec.The greater the speed, better is the performance.
Computers clock speed: every computer has an internal clock which measures the response of other devices connected to computer and synchronizes the speeds for optimum performance. It refers to rate at which the execution of commands takes place. Hence, higher the clock speed better is the performance.
A microprocessor incorporates most or all of the functions of a central processing unit (CPU) on single integrated circuit (IC) .The first microprocessors emerged in the early 1970s and were used for electronic calculators, using binary-coded decimal (BCD) arithmetic on 4-bit words. Capacity of microprocessors has been known to generally follow Moore's Law, which suggests that the complexity of an integrated circuit, with respect to minimum component doubles and cost halves every two years. Sliced wafer thin, silicon serves as an ideal conductor and insulator for transmitting electrical currents throughout the components of the chip. The finished product is an integrated circuit composed of layers of built-in wiring and transistors. The transistors form a set of registers. A multi-core processor is a single chip with more than one microprocessor, effectively multiplying the performance with the number of cores. Some components, such as cache, may be shared between cores. Because the cores are physically very close they interface at much faster clock rates compared to discrete multiprocessor systems.
Every motherboard has on it a specific processor socket type. This socket will determine the physical packaging of the AMD or Intel processor that can be installed on it. Hence it is necessary to choose motherboard with processor in view.
The number and type of expansion slots and connectors is important for what will be placed in the computer. If you require a specific connector or slot type, such as USB 2.0, Fire Wire or PCI-Express, you want to make sure that you get a motherboard that supports that type of connection. It is always possible to get an expansion card to add some connectors, but not all.
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