Learn more About Computer
A hard disk drive is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. Hard disks record data by magnetising a magnetic material in a pattern that represents the data. They read the data back by detecting the magnetization of the material.
The hard disk consists of a spindle which holds one or more flat circular disks called platters, on which the data is recorded. The platters are made from a non-magnetic material and are coated with a thin layer of magnetic material.
The platters revolve at very high speeds and information is written to platters as they rotate past read-and-write heads that operate very close over the magnetic surface. The read-and-write heads detect and modify the magnetization of the material immediately under it. There is one head for each magnetic platter surface on the spindle, mounted on a common arm. An actuator arm moves the heads roughly radially across the platters as they revolve, allowing each head to access the entire surface of the platter as it revolves.
Hard disks have sealed enclosure to protects the internal parts from dust, moisture, condensation, and other sources of contamination. The gap between read-write head and platter is only a few nanometers. Most Hard disks now revolve at 5,400 RPM (Revolutions Per Minute) and above.
Defragmentation of Hard Disk, a utility available in Windows (Start -> Programs -> System Tools -> Disk Defragmenter), once or twice a year increases the efficiency of the Hard Disk by reducing the seek time and results in the computer becoming faster. It is generally a good idea to remove programs/utilities, you no longer intend to use, to free system resources.
RAM is much faster to read from and write to than the other kinds of storage devices like hard disk, floppy disk, and CD-ROM available in a computer. However, the data in RAM stays there only as long as the computer is running. RAM is a volatile memory and when the computer is turned off, RAM loses its data. When the computer is turned on again, operating system and other files are once again loaded into RAM usually from the hard disk. If RAM become filled up, the processor needs to continually go to the hard disk to replace old data in RAM with new data which slows down the computer.
SDRAM, DDR RAM, DDR2 RAM and DDR3 RAM: These are all types of RAMs. SDRAM came first and is the slowest of these RAMs, followed over DDR RAM, then DDR2 RAM and then DDR3 RAM, with each providing greater memory speeds, at least potentially. A computer will use one of these memories according to the memory type supported by the motherboard. Generally, the newer the computer/motherboard, the faster the memory it will support.
The increasing of RAM improves the speed of a computer to an extent. Therefore increasing the RAM is a cheaper and convenient way to increase the speed of your computer to a limited extent.
Read Only Memory (ROM)
ROM is an acronym for Read-Only Memory. It refers to computer memory chips containing permanent or semi-permanent data. Unlike RAM, ROM is non-volatile. The contents of ROM remain even after the computer is switched off. A computer comes with a small amount of ROM containing the boot firmware. This consists of a few kilobytes of code that tell the computer what to do when it starts up, e.g., running hardware diagnostics and loading the operating system into RAM. On a PC, the boot firmware is called the BIOS.
Originally, the ROM used to be read-only and physical replacing of ROM chips was required to update programs written on the ROM. The new versions of ROM allow limited rewriting making it possible to upgrade firmware such as the BIOS by using installation software.
The BIOS is a special software usually stored on a Flash memory chip on the motherboard. It is used by the microprocessor (processor) to get the computer system started after it is turned on. It also manages data flow between the computer's operating system and attached devices such as the hard disk, video adapter, keyboard, mouse, printer etc. When BIOS boots up (starts up) the computer, it first determines whether all of the attachments are in place and operational and then it loads the operating system (or key parts of it) into the computer's random access memory (RAM) from hard disk or diskette drive.
The BIOS uses CMOS (Complementary Metal Oxide Semiconductor) technology to save any changes made to the computer's settings. A small lithium or Ni-Cad cell, installed on the motherboard, supplies power to keep the data for years. To enter the CMOS Setup for altering custom settings of a computer, a certain key during the initial startup sequence is required to be pressed. Most systems use "Del," or "F1," keys to enter CMOS setup.
On entering CMOS setup, a text menu screen, the contents of which are different for different BIOS manufacturers, is displayed. The menu screen provides links for opening pages for changing various BIOS settings of the computer. These menus enable change of the following
• System Time/Date
• Drive Configuration
• Boot Sequence - setting the order of boot devices;
• Plug and Play;
• Integrated peripherals;
• Advanced chipset features;
• Setting password for computer access;
• Power Management etc.
The changes to CMOS setup must be made very carefully. Incorrect settings may stop the computer from booting.
A sample Screen
A processor, also called microprocessor or Central Processing Unit (CPU), can be described as the "engine" or "brain" of the computer. A processor is a logic circuitry that responds to and processes the basic instructions that drive a computer. Two typical components of a CPU are:
- The arithmetic logic unit (ALU), which performs arithmetic and logical operations.
- The control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.
Dual-core and Multi-core Processors: A dual core processor is a CPU with two separate cores on the same die, each with its own cache. It's the equivalent of getting two microprocessors in one. To utilize a dual core processor, the operating system must be able to recognize multi-threading and the software must have simultaneity.
Multi-core is expansion to dual-core technology and allows for more than two separate processors on the same die. While a dual core system is faster than a single-core system, a multi-processor system is faster than a system with dual core processor, everything else remaining equal.
The Speed of a processor is specified in Megahertz which determines how many instructions per second the processor can execute.
A processor generates lot of heat when computer is on. Therefore, a heat sink with fan is installed over it to absorb the heat generated by the processor and protect it from burning out.
Intel and AMD are the two main manufacturers of computer processors.
Motherboard is the main electronic circuit board in the computer on which all components are mounted or connected. Motherboard can be described as the "heart" of the computer. A motherboard is the central or primary circuit board of the computer.
Most motherboards include:
- Socket(s) or slot(s) for mounting microprocessor(s)
- Slots for RAM memory chips
- Chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses
- Non-volatile memory chips containing the system's firmware or BIOS
- A clock generator which produces the system clock signal to synchronize the various components
- Slots for expansion cards
- Slots for IDE (Hard Disk Drive, CD ROM Drive etc.)
- Slot for Floppy Drive
- Socket for connecting power cable from SMPS for distributing power to the CPU, chipset, main memory, expansion cards and other components and devices in the CPU box.
- Connecting panel for connecting various Input and Output devices located outside the CPU box viz. Monitor, Keyboard, Mouse, Printer, USB Drive etc.
Motherboards are different for different processors i.e. a motherboard for Intel Pentium III processor cannot be used for a Intel Pentium IV or AMD Athlon processor. Therefore, if anyone desires to upgrade his computer to a new faster processor, he will be required to change the motherboard also.
The motherboard picture above shows a motherboard with details of mounting /connecting major components and the connecting panel picture shows connection of various Input and Output devices to the motherboard
.