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How Computer Hardware Works

COMPUTER HARDWARE BASICS

MICROPROCESSOR:

Microprocessor is the mind of any computer. It controls all activities contained in the computer. Principally it performs 2 forms of operations - arithmetic & logical operation (internally), learn & write (externally). Read /write operations are performed on 2 kinds of units - I/O and reminiscence devices. It uses the "address bus" to pick any "location" on these units, sends a learn/write signal over the "control bus" and then the information over the "knowledge bus".

 

MEMORY DEVICES:

 

The CPU stores all info in the computer's memory. There are two memory varieties - RAM & ROM

 

RAM (Random Access Memory):

 

This unstable type is a read & write memory device. This loses its contents when power is shut off.

 

The forms of RAM are

 

· DRAM (Dynamic ram) - is just like a capacitor, because it tends to lose its contents and hence requires to be refreshed. That is the Pc RAM.

 

· SRAM (Static ram) - Is faster than Dram and would not require to be refreshed. This is pricey and therefore only a limited quantity is used as CACHE memory within the computer.

 

ROM (Read solely reminiscence):

 

ROM could be programmed using a programmer after which it acts as a "learn solely" device. This gadget is used as the textbook for the CPU within the computer and known as ROM BIOS. It stores all the essential info of programming the devices present inside the system as well as the POST (Energy On Self Check) sequence. AMIBIOS and AWARD BIOS are the most common ROM BIOS.

 

The forms of ROM are

 

· PROM (Programmable Learn Only Memory)

 

· EPROM (Erasable & Programmable Read Only Memory)

 

· FLASH ROM

 

· EEPROM (Electrically EPROM)

 

· EAPROM (Electrically Alterable ROM)

 

I/O DEVICES:

 

Other than passive reminiscence devices, there are particular controllers in the system, which assist the CPU in performing varied operations. These are referred to as I/O devices. These gadgets include Interrupt controller, Timer, Ports, DMA Controller, Floppy Drive Controller, CRT Controller etc.

 

BUSES & EXPANSION SLOTS:

 

These are the means through which communication between numerous devices of the pc takes place and the kinds are as talked about below.

 

ISA (Business Standard Architecture):

 

ISA bus consists of a 24-bit deal with bus and the 16-bit data bus. ISA can help 8MHZ clock speed.

 

MCA BUS (Micro Channel Architecture):

 

MCA bus is offered both in 16 bit or 32 bit versions. It was developed in a brand new line of computers referred to as the PS/2 (private system 2). The clock pace is barely sooner (10MHZ as a substitute of 8MHZ).

 

EISA BUS:

 

EISA has a 32-bit Handle and Knowledge bus and 10MHZ CLK speed.

 

VL BUS/VESA LOCAL BUS:

 

It's a 32-bit bus which was positioned local to the CPU and therefore its name. Due to this fact it could help excessive bus speeds (that of the CPU).

 

PCI BUS:

 

PCI has many advantages over other bus types. Initially, it supports 64 bit and 32-bit information paths. So it may be used each for 486 and Pentium based mostly systems. PCI can run as much as 33MHZ pace and has the advantage of being isolated from the CPU. INTEL developed this bus.

 

PCMCIA: (PC Reminiscence Card International Association):

 

The PCMCIA was first designed for expanding the memory in small, dealt with computers. PCMICIA'S bus width is just sixteen bits, however a 32-bit model is on its way. There are three forms of playing cards namely

 

· Type 1 (3.3 m thick)- used for memory card.

 

· Sort 2 (5 mm thick)- used for modem and LAN adapter.

 

· Sort 3 (10.5 mm0 thick) - used for commonest applications like PC laborious disk Cards.

 

ADD ON CARDS:

 

These are cards plugged on to the main board, the mom board (The one that homes the CPU & RAM/ROM Bios). Each performs specific functions of interfacing the Motherboard to peripheral machine like mouse, Monitor etc. Some Add-ons are discussed below.

 

DISPLAY ADAPTER:

 

These interface the motherboard with the monitor and there are a number of sorts of cards. The variations are in resolution, no. Of colors supported and speed.

 

CGA (Color Graphics Adapter)

 

640 X 200 pixels

 

MDA (Mono Display Adapter):

 

eighty characters broad 25 strains lengthy

 

EGA (Enhanced Graphics Adapter):

 

640 X 350 mode

 

VGA (Video Graphics Adapter):

 

Advanced versions of SVGA/TVGA which begin from a decision of 640 X 480 pixel

 

AGP (Accelerated Graphics Port):

 

Introduced in the celeron/P II primarily based systems, this caters to the demanding multimedia functions with its excessive performance.

 

IDE I/O CARD:

 

Helps the following functions.

 

SERIAL PORT:

 

Communication exterior to the pc is completed serially (bit after bit) by means of this port. It is used to attach communication units like mouse, modem etc.

 

PARALLEL PORT:

 

eight Bit knowledge switch takes place between the pc and an external device. It's typically used to connect a printer.

 

GAME PORT:

 

It is used to connect a joystick for taking part in games.

 

IDE (Integrated/Intelligent Drive Electronics) Interface: This interface is used to communicate with IDE Onerous disks.

 

FLOPPY DISK CONTROLLER:

 

The FDC can help up to floppy disk drives. The FDC is connected to the system bus and to the DMA controller. It performs data switch in DMA mode.

 

SOUND CARD:

 

This is the cardboard that adds audio results to the pc by providing interface with microphone and speaker. This is used in Multimedia Computers.

 

PERIPHERAL DEVICES:

 

FLOPPY DRIVES:

 

1.forty four MB & 1.2 MB are varieties of popular Floppy Drives.

 

HARD DISK DRIVES:

 

ST 506 & ESDI are previous types. IDE laborious disks are well-liked as a result of their value to efficiency ratio may be very good. For very high efficiency, SCSI (Small Pc Systems Interface) is the ideal option, if value isn't a criterion.

 

CDROM DRIVES:

 

CDROM drive is used in a multimedia system as it can help all sorts of CD ROMs - be it data CD, Audio CD, Video CD. It has an ideal advantage of storing about 650 MB of information in a single CD.

 

KEYBOARD:

 

Keyboard translates the keystrokes into letters or numbers. These letters are interpreted and the computer CPU depending executes commands on what was sent. Variations when it comes to XT/AT, no. of keys, sort of keys used may be observed.

 

MOUSE:

 

To interact with the photographs (ICONS), a special pointer machine was launched into the pc world. This gadget is named mouse and is connected to the serial port.

 

The mouse comprises a round ball that makes contact with rollers-one for X-axis (the horizontal) and one for Y-axis (the vertical). Shifting the mouse causes the ball to roll, and the ball, which is in contact with the 2 rollers, causes them to turn. That is used for moving clicking the mouse buttons makes a pointer head on the screen and selection.

 

SCANNERS:

 

Along with keyboards and pointing units, there's one other quite common methodology of getting data into the computer. A Scanner is used to scan a picture (say from a photo) and modifying could also be finished using a suitable software.

 

MONITORS:

 

The monitor receives video indicators from the computer video adapter card and displays the video info as pixels (picture parts) on the monitor screen. Quite a lot of displays starting from CGA mono to SVGA color are available for users to choose from (although the former is completely obsolete).

 

CONFIGURATION SETUP:

 

That is where we outline the system configuration. This is carried out only when the system is assembled and configured for the first time or when it's upgraded. (One may enter the SETUP by urgent "Del" key as the system is powered up). Completely different BIOS' support different options however the most important ones, which are found on all techniques, are listed below.

 

DATE & TIME: It displays the proper Date & Time. It must be set when system is first installed.

 

FLOPPY TYPE:

 

To define the Floppy drives related (1.2MB or 1.44MB).

 

HARD DISK TYPE: To pick out the Arduous disk sort (Primary or secondary)

 

DISPLAY TYPE: Its select the forms of video adapter used for the system monitor.

 

CACHE ENABLE/DISABLE:

 

This category accelerates the Reminiscence access. (Default worth: Allow) and defines presence or absence of cache memory.

 

QUICK POWER ON SELF TEST: Its accelerates the Energy On Self Check after you power up the computer.

 

PASSWORD SETTING: This allows you to set the System password.

 

POWER MANAGEMENT: This class permits you to select the sort (or diploma) of power saving.

 

LOADING DEFAULT VALUES:

 

There are lots of parameters, which should be defined in the CMOS setup, and one may not wish to do so manually. This feature masses sure default values, stored in the BIOS ROM, which have been defined by the manufacturer for optimum system performance.

 

ENABLE/DISABLE ON BOARD FUNCTIONS:

 

To enable/disable certain onboard functions like Floppy Disk Control and so on (This applies only to integrated Motherboards where the ADD ON functions are built-in on the Motherboard itself).

 

PNP FEATURES: This class is used to configure the PCI Bus slots.

 

IDE AUTO DETECTION: This lets you detect the IDE Hard drives automatically.

 

SAVING & EXITING:

 

This allows you to save the new setting value in the CMOS memory and continue with the booting process.

 

POST (POWER ON SELF TEST):

 

This POST firmware is saved in ROM on the motherboard. This POST is a series of a simple program to test and catch faults in several parts and circuits. It exams the microprocessor, interrupt controller, PPI, DMA controller, ROM, RAM, peripheral controllers etc.

 

SYMPTOMS:

 

In case of error detection throughout POST, indications like error beeps/error messages helps troubleshoot problems.

 

SPEAKER:

 

With the assistance of speaker error beeps, we are able to troubleshoot faults. Each fault causes the speaker to emit completely different patterns of beeps.

 

DISPLAYED ERROR MESSAGES:

 

When system is powered on, error message shall be displayed on the display screen (Floppy disk fail), if the Video Adapter is functional.

 

DIAGNOSTIC CARDS:

 

The advanced diagnostic add on card captures particulars of POST sequence and shows a hexa code which may be used for in-depth & correct diagnosis of a POST problem.

 

CDROM DRIVES:

 

A computer CD-ROM drive makes use of small, interchangeable, plastic-encased discs from which information is retrieved using a laser beam, very similar to music compact disc. And like a music CD, a computer CD-ROM shops huge quantities of information. That is achieved by using gentle to report data in a kind that is extra tightly packed than the relatively clumsy magnetic read/write heads a traditional drive should manage.

 

The drive is controlled by a software program in your PC that sends instructions to controller circuitry that is both part of the computer systems motherboard or on a separate board put in in an growth slot.

 

How a CD_ROM drive works?

· A motor always varies the speed at which CD-ROM disc spins in order that no matter where a part, known as DETECTOR, is located in relation to the radius of the disc, the portion of the disc immediately above the detector is all the time on the similar speed.

 

· The laser initiatives a concentrated beam of sunshine that is additional targeted by a focusing coil.

 

· The laser beam penetrates a protective layer of plastic and strikes a reflective layer that appears like aluminum foil on the underside of disc.

 

· The floor of the reflective layer alternates between lands and pits. Lands are flat floor areas; pits are tiny melancholy within the reflective layer. these floor are record of the 1s and 0s used to retailer data.

 

· Lights that strikes a pit scattered. But mild that strikes a land is reflected instantly back on the detector, where it passes via a prism that deflects laser beam to a LIGHT-SENSING DIODE.

 

· Each pulse of sunshine that strikes the sunshine-sensing diode generates a small electrical voltages. These voltages are matched towards a timing circuit to generates a stream of 1s and 0s that may understand.

This post is written by John Lewis, who also always writes about other topics such as sterling silver jewelry, cz jewelry & Sterling Silver Necklace.

does it matter if we plug a PCI card into an ISA slot ?if so,why?

Besides all of the technological reasons that it won't work, it won't fit into the slot.

The Amiga 2000 Computer (1987)