Different Types of Memory

Memory - Types and Speed

This section will examine the LO1 component regarding different types and speed of computer memory.

The memory in a computer system can be divided into:

• Random Access Memory (RAM)

• Read Only Memory (ROM)

RAM is temporary storage that the processor uses to store programs, and their associated data, while they are running. The idea of a program running from a computer's main memory is known as the 'stored program concept'. When invoked a program will be loaded from hard disk into RAM and any data entered is stored in RAM as well. RAM is volatile, which means that its contents are lost when the machine is turned off.

Memory size and speed, along with the processor type and speed, are factors which affect system performance. The more memory a machine has the faster it will be because the processor does not have to spend as much time transferring blocks of program code into RAM. The faster a processor can read and write to memory can also boost a machines performance

Types of RAM

There are different types of RAM that are used in computer systems, each having its own features and uses.

Memory types include:

Description	Picture
30-pin SIMM (Single In-line Memory Module)
72-pin SIMM
168-pin DIMM (Dual In-line Memory Module)
184-pin DIMM

The text descriptions refer to the different physical packaging of memory chips. This packaging is the placement of individual memory chips on a printed circuit board (PCB) which is designed to be easily inserted or connected to the motherboard.

Within each of the types there are different speeds, capacities and architecture. This means that even although a memory module could fit into a memory slot on the motherboard it may not work and that reference should be made to the motherboard documentation when installing new memory.

Connecting RAM to the Motherboard

Depending on the type and specification of memory modules there are different ways of connecting them to the motherboard. All memory modules are designed in such a way that there is only one correct way of attaching them to the motherboard. This could come as a gap or gaps along the bottom of the module or at the side.

SIMMs are typically inserted into their slot at an angle and then pushed forward until they click home, whereas DIMMs go straight into the slot and are pushed down until the two clips are either end of the module slip into place securing the module.

Note: Always handle RAM modules by their edges and avoid touching the metal contacts at the bottom.

Dynamic RAM

Dynamic Random Access Memory (DRAM) is the most common type of main memory found in computer systems. This type of memory is dynamic because its storage cells must be refreshed, i.e. receive a new electronic charge every few milliseconds in order for the memory state to be maintained, e.g. a '0' or a '1'.

Read Only Memory (ROM)

Read Only Memory (ROM) is a special type of non volatile memory that is used for certain functions, e.g. to store the computer system's Basic Input/Output System and also to store instructions that are required to be carried out when the computer is first switched on, e.g. Power On Self Test (POST). This test is used to check all of the hardware attached to the computer to see if it is working. If something fails the POST, e.g. a RAM fault, then the computer will issue a series of audible beeps. For each possible error there is a different set of beeps.

Once the computer has completed its POST it will look at its ROM and carry out the other instructions stored there. One of the key instructions is that to tell the computer to boot up the operating system.

Types of ROM

There are different variations on the classic ROM chips which were manufacturer produced and could not change. The most common are:

Programmable Read-Only Memory (PROM)

This type of ROM can be re-programmed by using a special device called a PROM programmer. Generally, a PROM can only be changed/updated once.

Erasable Programmable Read-Only Memory (EPROM)

This type of ROM can have its contents erased by ultraviolet light and then reprogrammed by an RPROM programmer. This procedure can be carried out many times; however, the constant erasing and rewriting will eventually render the chip useless.

Electrically Erasable Programmable Read-Only Memory (EEPROM)

This type of ROM works in a similar way to Flash memory in that it can its contents can be 'flashed' for erasure ad then written to without having to remove the chip from its environment. EEPROMs are used to store a computer system's BIOS, and can be updated without returning the unit to the factory. In many cases, BIOS updates can be carried out by computer users wishing a BIOS update.

Flash Memory

Flash memory is an example of quite a recent type of storage technology known as solid state devices. This type of portable storage has become very popular because of its low price and high storage capacity compared to its rivals, e.g. floppy disk.

Solid state devices are regarded as being robust and reliable because they have no moving parts with the data stored in semiconductor chips. This technology already exists in the form of flash memory used to store the Basic Input/Output System (BIOS) of a motherboard.

Unlike ROM, flash memory can be read form and written to and unlike RAM does not require power to retain its data.

Although these devices typically cannot hold as much data as hard disks, CD-ROMs and DVDs, the storage capacity is continually increasing.

Types and Applications of Flash Memory

Common applications for solid state disks are digital cameras, camcorders and Personal Digital Assistants (PDAs). Solid state disks can also be used to transfer data from PC to PC.

Most solid state disks can be attached to a USB port, however, some disks need to be inserted into a special drive or card reader.

There are four common formats for solid state disk. They use similar technology but have differences in physical format and interfacing.

• CompactFlash
• SmartMedia
• Memory stick
• USB Flash Drive

Different Types of Processor

What is a Processor?

A processor or micro-processor is the 'brains' of a computer system. It is the processor that controls the working of all of the hardware and software.

The processor is sometimes referred to as the Central Processing Unit (CPU).

There are many processors available and processor specification is usually one of the first things considered when buying a new personal computer (PC). The type of processor and its speed have the greatest impact on the overall performance of a computer system. Processor performance is related directly to its speed of operation and its architecture

Competition among processor manufacturers is fierce and because of this there is a wide and diverse choice of processors in the market place. Processor manufacturers, such as Intel and Advanced Micro Devices (AMD) are continually developing more advanced processors and new models are released within the space of months rather than years. This is in stark contrast to earlier processor developments, such as the 8086, 80286 and 80386 which were released years apart.

Types of Processor

A processor connects directly to the computer's motherboard. Processors can be categorized by the way they are connected to the motherboard.

There are two main types of processor connections to motherboards:

• Sockets

• Slots

Processor Sockets

The type of processor that is connected to a socket is a square package with many pins (more than 250) on the bottom surface of the chip, which connects to a motherboard by a Zero Insertion Force (ZIF) socket. The pins are found around all sides of the package and there will be more than one row of pins on each side.

Processor Slot

The other form that processors take is a chip soldered on to a card, which then connects to a motherboard by a slot similar to an expansion slot. The picture slows a slot for a Pentium 3 processor.

Example Slot Processors

This picture shows a side view of a Pentium 3 processor housing including heat sink, cooling fans and power connectors. Note, the gap in the circuit board; this is here as a guide to the installer so that the processor is not incorrectly connected.

This picture shows the Pentium 3 Processor face on.

Processor Heatsinks

Due to the amount of heat generated during normal computer operation modern processors require some method of temperature control. This task is generally carried out by a heatsink. This is an aluminium alloy device, equipped with fins, that is used to dissipate heat. As well as the heatsink processors will also have a small fan attached to help reduce the build-up of heat.

Different Types of mother Board

Motherboard explained

The motherboard is the main component of any branded or assembled PC, laptop, tablet or a mobile phone. Now you must be curious, why it is called the motherboard? The motherboard is a Printed Circuit Board which acts as the main platform for communication between all other components of a system. All the other computer parts are either directly installed or connected to various motherboard components and all the data is transferred between them through the motherboard.

Different types of motherboards:

AT Motherboards

The oldest of the main boards, these motherboards were used in earlier 286/386 or 486 computers. The AT means the board consists of advanced technology(AT) power connectors. There are two power connectors of 6 pin each mounted on the AT motherboards. The AT motherboards were available in the early 80’s.

ATX Motherboards

The ATX motherboards started in 90’s and are still available. The ATX connector on the motherboard consists of a single connector. These boards are used for P2/P3 or P/4 processors.

Motherboard for P1/P2 processors:

Pentium 4 motherboard

Motherboard Components

The motherboard consists of various components which have their own role to play in the functioning of a computer. Let us discuss various motherboard components and know their definition and role.

Expansion Slots

ISA slots. These were the oldest expansion slots in the history of motherboards. They were found in AT boards and are identified by black color. Conventional display cards or sound cards were installed in these slots. The full form of ISA is Industry Standard Architecture and is a 16- bit bus.

PCI Slots. The full form of PCI is Peripheral Component Interconnect. The PCI slot is one of the important motherboard components today and is vastly used to install add-on cards on the motherboard. The PCI supports 64-bit high-speed bus.

PCI express. Also known as PCIe, these are the latest and the fastest component of the motherboard to support add-on cards. It supports full duplex serial bus.

AGP slot. Accelerated graphics port(AGP) is specifically used to install a latest graphics card. AGP runs on a 32-bit bus and both PCIe and AGP can be used to install high-end gaming display cards.

RAM(memory) slots

SIMM slots. The full form is a single in-line memory module. These slots were found in older motherboards, up to 486-boards. The SIMM supports 32-bit bus.

DIMM slots. The full form of DIMM is a Double inline memory module. These are the latest RAM slots which run on a faster 64-bit bus. The DIMM used on Laptop boards are called SO-DIMM.

CPU Socket

Another vital motherboard component is the CPU socket which is used to install the processor on the motherboard. Some important sockets are explained below.

Socket7. It is a 321 pin socket that supported older processors like Intel Pentium 1/2/MMX, AMD k5/K6, and Cyrix M2.

Socket370.  It is a 370 pin socket that supports Celeron processors and Pentium-3 processors.

Socket 775. It is a 775-pin socket that supports Inter dual core, C2D, P-4 and Xeon processors.

Socket 1156. Found on latest types of motherboards, it is an 1156-pin socket that supports latest Intel i-3, i-5 and i-7 processors.

Socket 1366. The socket is of 1366 pins and supports latest i-7 900 processors.

BIOS

The full form of BIOS is Basic Input Output System. It is a motherboard component in the form of a Integrated chip. This chip contains all the information and settings of the motherboard which you can modify by entering the BIOS mode from your computer.

CMOS Battery

The battery or a cell is a 3.0 Volts lithium type cell. The cell is responsible for storing the information in BIOS and the full form is Complementary Metal Oxide Semi-Conductor.

Power Connectors

In order to receive power from SMPS, there are connectors mounted on the motherboards.

AT connector. It consists of 2 number of 6 pin male connectors and is found on old types of motherboards.

ATX connector. The latest in the series of power connectors, they are either 20 or 24 pin female connectors. Found in all the latest types of motherboards.

IDE connector

The Integrated Drive Electronics (IDE) connectors are used to interface disk drives. The 40-pin male connector is used to connect IDE hard disk drives and the 34-pin male connector connects to Floppy Disk Drive.

SATA connector

Latest in the series, the connectors, Serial Advance Technology Attachment(SATA) are 7-pin connectors to interface latest SATA hard disks or optical drives. They are much faster than IDE interface.

Co-Processor

The co-processor is one of the important motherboard components and helps the main processor in mathematical calculations and computer graphics.

Cabinet connections

The cabinet in which the motherboard is installed has many buttons that connect to the motherboard. Some of the common connectors are Power Switch, Reset Switch, Front USB, Front Audio, Power indicator(LED) and HDD LED.

I/O interface connectors

Choosing a right type of motherboard that is compatible with other parts of computer is vital step in determining the overall speed of your PC. Once you learn about various motherboard components, you can easily assemble your own PC or solve the basic hardware issues in motherboard.

Different Types of SMPS

Power supply circuit plays an essential role in every electrical and electronic circuit to provide the electrical power to the owl circuit or loads like machines, computers, etc. These different loads require different forms of power at various ranges and characteristics. So, the power is converted into the desired form by using different power converters. Basically, different loads work with various types of power supplies like SMPS (switch mode power supply), AC power supply, AC to DC power supply, programmable power supply, high voltage power supply & uninteruptable power supply.

What is SMPS (Switch-Mode Power Supply)?

SMPS is defined as, when the power supply is included with the switching regulator from converting electrical power from one form to another form with necessary characteristics is called switch mode power supply. This power supply is used to attain regulated DC o/p voltage from the DC i/p voltage or unregulated AC.

SMPS

SMPS is a complicated circuit like other power supplies, it supplies from a source to the loads. MPS is crucial for different electrical and electronic appliances which consumes power and also for designing electronic projects.

Topologies of SMPS

Topologies of SMPS are categorized into different types such as AC-DC converter, DC-DC converter, Forward Converter and Flyback converter.

Working principle of Switch Mode Power Supply

The working of a switch mode power supply topologies is discussed below.

DC-DC Converter SMPS Working

In this power source, a high voltage DC power is directly acquired from a DC power source. Then, this high voltage DC power is switched usually in the range of 15KHz-5KHz. And, then it is fed to a step down transformer unit of 50Hz. The o/p of this transformer is fed to the rectifier, them this rectified o/p power is used as a source for loads, and the oscillator ON time is controlled and a closed loop regulator is formed.

DC to DC converter SMPS

The switching-power supply o/p is regulated by using Pulse Width Modulation shown in the above circuit, the switch is driven by the PWM oscillator, then indirectly the step down transformer is controlled when the power fed to the transformer. Therefore, the o/p is controlled by the pulse width modulation, as this o/p voltage and PWM signal are inversely proportional to each other. If the duty cycle is 50%, then the max power is transferred through the transformer, and if the duty cycle drops, then the power in the transformer also drops by decreasing the power dissipation.

AC -DC Converter SMPS Working

This type of SMPS has an AC i/p and it is converted into DC by using rectifier & filter. This unregulated DC voltage is fed to the power factor correction circuits as it is affected. This is because around the voltage peaks, the rectifier draws short current pulses having significantly high-frequency energy that affects the power factor to reduce.

AC to DC converter SMPS

It is almost related to the above discussed converter, but in the place of DC power supply, here we have used AC i/p. So, the mixture of the rectifier &filter, this block diagram is used for converting the AC to DC and the switching operation is done by using a power MOSFET amplifier. The MOSFET transistor consumes low on-resistance & can resist high currents. The frequency of the switching is selected such that it must be kept low to normal human beings (above 20KHz) and action of switching is controlled by a feedback using the PWM oscillator.

Again, this AC voltage is fed to the o/p of the transformer shown in the above figure to step up or step down the levels of voltage. Then, the this transformer’s o/p is rectified & smoothed by using the o/p filter and a rectifier. The o/p voltage is controlled by a feedback circuit by likening it with the reference voltage.

Fly-back Converter SMPS Working

The SMPS circuit which has very low o/p power (less than 100W) is called as fly-back converter SMPS. This type of SMPS is very low and simple circuit compared with other SMPS circuits. This type of SMPS is used for low power applications.

Fly-back Converter type SMPS

The unregulated i/p voltage with a constant magnitude is changed into a preferred o/p voltage by switching fast using a MOSFET; the frequency of switching is around 100 kHz. The voltage isolation can be attained by using a transformer. The operation of the switch can be controlled by using a PWM while executing a practical fly-back converter.

Fly-back transformer shows dissimilar characteristics compared to normal transformer.Fly-back transformer includes two windings which acts as a magnetic coupled inductor. The o/p of this transformer is delivered through a capacitor and diode for filtering as well as rectification. As shown in the above figure, the o/p of the SMPS can be taken as voltage across the filter capacitor.

Forward Converter type SMPS Working

This type of SMPS is almost same to the fly back converter type SMPS. But, in this type of SMPS a control is connected at the o/p of the secondary winding of the transformer to control the switch. As compared to the fly back converter, the filtering and rectification circuit is complicated.

Forward Converter type SMPS

This is also called as a DC-DC buck converter, along with a transformer which is used for scaling and isolation. In addition to the “D1” diode & “C” capacitor, an inductor L & a diode D are connected at the end of the o/p. If ‘S’ switch gets switched ON, then the i/p is given to the transformer’s primary winding. Therefore, a scaled voltage is produced at the transformer’s secondary winding.

Therefore, the D1 diode gets forward biased & scaled voltage is passed through the LPF proceeding the load. When the switch S is turned ON, then the currents through the winding reaches to zero, However the current through the inductive filter & load cannot be changed shortly, and a lane is offered to this current by the coasting diode D2. By using the filter inductor, the required voltage across the D2 diode & to keep the electromagnetic force necessary for maintaining the stability of the current at inductive filter. Even though the current is falling against the o/p voltage, almost the constant o/p voltage is sustained with the existence of the large capacitive filter. It is regularly used for various switching applications with a 100 W to 200 W power range.

This is all about switch mode power supply and its types which involves Buck converter, Buck-boost converter Self Oscillating fly-back converter, Boost converter, Cuk, Sepic, Boost-buck. But, a few types of SMPS’s are discussed in this article they are AC-DC converter, DC-DC converter, Forward and Fly-back converter. Furthermore, any information regarding the types of SMPS, fell free to give your feedback to give your suggestions, comments in the comment section below.

What is Switching Mode Power Supply (SMPS) And its Application?

Switch Mode Power Supply

The power supply circuit in any electrical and electronic circuit plays a vital role to give the power to the entire circuit. The different circuits require various kinds of power at different ranges and characteristics. So, the power is changed into the required form by adopting different power converters. Fundamentally, different types of circuits work with various kinds of power supplies such as SMPS. The term SMPS stands for switch mode power supply, AC to DC power supply, AC power supply, high voltage power supply programmable power supply, and UPS (uninterruptible power supply).

What is a Switch Mode Power Supply?

The term SMPS is defined as when the power supply is involved with the switching regulator to change the electrical power from one form to another form with required characteristics is called SMPS. This power supply is used to achieve regulated DC output voltage from the DC input voltage (or) unregulated AC. SMPS is a complex circuit such as other power supplies, it provides the supply from a source to the loads. SMPS is very important for different appliances which consume power and also for making electronic projects.

SMPS

Working Principle of an SMPS

A switching regulator does the regulation in the switch mode power supply. A series switching element switches the current supply to a smoothing capacitor turn ON and OFF. The voltage on the smoothing capacitor controls the time when the series element is switched. The constant switching of the capacitor keeps the voltage at the necessary level.

SMPS Circuit

AC power first flows through the fuses & a line filter, then it is resolved by a full wave bridge rectifier. The voltage which is resolved is next used to the PFC (power factor correction) pre-regulator followed by the downstream DC to DC converter. Most of the computers and small machines utilize IEC (International Electrotechnical Commission) style i/p connector. As for o/p connectors and pinouts, excluding for some industries like PC & compact PCI. In general, they are not consistent and are left up to the manufacturer.

Like every electronic device, the switch mode power supply also comprises some active & passive components. And like each of those devices, it has its own benefits and drawbacks.

Different Types of SMPS

The different types of SMPS include the following

• D.C. to D.C. Converter
• Forward Converter:
• Flyback Converter
• Self-Oscillating Flyback Converter

DC-DC Converter

The main power received from the AC main is resolved and filtered as high voltage DC. Then, it is changing at an enormous rate of speed and fed to the main side of the step-down transformer. This transformer is only a segment of the size of an equivalent 50 Hz unit, thus releasing the size and weight problems. The filtered and rectified o/p at the minor side of the transformer. Then it is now sent to the o/p of the power supply. A sample of this o/p is sent back to the button to control the o/p voltage.

D.C to D.C Converter

Forward Converter

In a forward converter, the choke transmits the current when the transistor is leading as well as when it is not. The diode transmits the current through the OFF period of the transistor. Thus, the flow of current into the load during both the periods. The choke stores energy during the ON period and also permits some energy into the o/p load.

Forward Converter

Flyback Converter

In this converter, the magnetic field of the inductor supplies the energy throughout the ON period of the switch. The energy is collapsed into the o/p voltage circuit when the button is in the open state. The duty cycle controls the output voltage.

Flyback Converter

Self-Oscillating Flyback Converter

This is the most simple converter based on the principle of the flyback. Throughout the conduction time of the switching transistor, the flow of current through the transformer primary switches ramping up linearly with the angle equal to Vin/Lp. The induced voltage in the secondary winding and the feedback winding make the fastest recovery rectifier reverse biased and hold the conducting transistor ON. When the primary current touches a peak value ‘Ip’, where the core activates to saturate, the current inclines to increase very sharply. This cannot be supported by the fixed base drive offered by the feedback winding. As a result, the switching activates to come out of saturation.

Features between SMPS and Linear power Supply

Features	Linear Power Supply	SMPS
Efficiency	25-50 %	65-75 %
Temperature rise	50-100oC	20-40oC
Ripple value	Even 5 mV possible	Higher 25-50 mV
Overall regulation	0.1 %	0.3 %
RF interference	None	Can cause problem if not properly shielded
Magnetic material	Stalloy or CRGO core	Ferrite core
Weight	20-30 W\kg	About 60 W\kg
Reliability	More reliable	Depends on the switches
Transient response	Faster	Slower (in ms)
Complexity	Less	More

Advantages and Disadvantages

• The main advantage of the SMPS is greater efficiency than linear regulators because the switching transistor dissolves little power when working as a switch.
• The size of SMPS is a smaller size and lighter in weight from the removal of heavy line frequency transformers, and similar heat generation. The standby power loss is frequently much less than transformers.
• Disadvantages of SMPS include better complexity, the generation of high-amplitude, the high-frequency energy that the LPF must block to avoid EMI (electromagnetic interference), harmonic frequencies, and a ripple voltage at the switching frequency.
• The low-cost SMPSs may pair electrical switching noise back onto the main power line, causing interference with equipment connected to the similar phase. Non-power factor corrected power supplies also source harmonic distortion.

Applications of SMPS

The applications of SMPS include the following

• Security Systems
• Machine Tool Productions
• AV products
• Support supplies for PLCs

Applications of SMPS

Furthermore, the SMPS is intended to make more efficient doing the most effective conversion process. The main focus of engineers in building the SMPS efficient includes Higher o/p power, low voltage, power density and Using a switching device such as Schottky diode.We hope that you have got a better understanding of this concept or to implement any electrical projects, 

Pictures Of Basic Computer Parts

Pictures Of Basic Computer Parts


Inside any computer you will find some basic parts. The basic parts are the minimum required for a computer to function properly in any application. So we have the outer case, the motherboard, the microprocessor, the video card, the memory, the network interface card, the hard drive, the sound card, the floppy disk drive and the optical drive.

<-336×280 Large Rectangle – center->

You will be provided below with a list of computer parts, each with its description and descriptive picture in order for you to understand better which is which and what is does.

Let’s start with the motherboard, which is one of the main parts without which the computer cannot work. It’s practicaly the support for the other parts which are attached to it, and it’s main role is to create the links between all the pieces you have in your computer.

Followed by the processor, or the microprocessor which is the central unit of information processing of a computer, which coordinates the system and which physically presents as an electronic chip. It controls the activities of the whole system and can process the user’s data. It’s the main element of a computer system; the chip, that is placed on the motherboard is very complex, and can reach up to millions of transistors. The microprocessor insures the data and instruction processing, both from the operating system as the ones from inside the user’s applications; it reads, process and control the applications and executes or supervises the information transfer and controls the general activity of the other components that make up the system.

The video card, or graphics accelerator card, is an expansion card whose function is to generate and output images to a display

The RAM, or the Random Access Memory, is the generic name for any type of memory that can be:

- random accessed, offering direct access to any of its location or address in any order, even randomly;

- implemented on electronic chips (and not on magnetic or optical devices as the hard disks or CDs).

The network interface card, or LAN adapter, is an expansion card designed for allowing the computers to connect to a network of computers.

The hard drive, or hard disc, is an electro-mechanical device for data storage or saving. Data saving is done on a magnetic surface on the rounded metallically cups.

The sound card, or the audio card, is a computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs.

The CD-ROM, or the Compact Disc Read-Only Memory: is a pre-pressed compact disc that contains accessible data to a computer for data storage and music playback. The CD-ROM doesn’t allow the computer to write anything to a CD.


The Floppy Disk Drive, or floppy drive, diskette drive, 3.5 inch drive, 5.25 inch drive, reads data from and writes data to a small disk. The most common type is the 3.5 inch drive followed by the completely 5.25 inch drive, among other sizes.

So now you know how basic computer parts look like and what are used for. We hope this information has been useful and has answered your questions and doubts about computer parts.

Overview of motherboards (part 2)

This posed a problem for full length expansion cards because the height of the processor interfered with proper card installation. In addition, heat dissipation from the processor sometimes caused problems for the expansion cards. The AT form factor also caused problems with the drive bays. The width of the board was 12" wide and 13.8" deep which overlapped with the space required for drive bays.


The Baby AT was a smaller version of the AT, only 9" wide and 13" deep, with newer, smaller components. It was a more compact board, but had the same drawbacks as the AT. In a home PC this is rarely an issue. However, in servers, many expansion cards are full length. Traditionally servers are not designed around the Baby AT form factor.

As motherboards have evolved over the years, the AT/Baby AT form factors have become obsolete.

ATX

The ATX form factor was designed to overcome the problems associated with the AT/Baby AT form factors. As shown in Figure B, the ATX component layout is different from the AT. In the ATX form factor, the processor and memory are arranged at a right angle to the expansion slots, allowing room for the use of full-length expansion cards. In the newer computers, the combined height of the processor, heat sink, and cooling fan make it possible to insert full length cards in any other form factor, and most new computers (including servers) are built around the ATX form factor.

The ATX form factor is different than that of the AT/Baby AT form factor

ATX motherboards also offer advanced power management features that make them ever more attractive to computer builders. For example, ATX motherboards offer a soft shutdown option, allowing the operating system to completely power down the computer without the user's having to press the power switch.

A full size ATX board is 12" wide and 9.6" deep. There is also a smaller version referred to as the Mini-ATX board, is 11.2" wide and 8.2" deep.

MicroATX

The MicroATX, introduced by Intel in 1997, is a compatible variation to the ATX board outlined above. As the name would imply, the MicroATX is smaller than the standard ATX board because of the reduced number of I/O slots on the board. Due to the fact that it is smaller than the standard ATX board, the MicroATX form factor reduces the cost of computers and is often used in lower-cost systems.

FlexATX

The FlexATX form factor was released by Intel as an addition to the MicroATX. This form factor, which is smaller than the MicroATX, is designed for lower-end, smaller, consumer orientated systems. Some FlexATX boards do not even include expansion slots which mean expansion is only possible through USB or firewire ports.

LPX

The LPX form factor is not a standard one but a non-standard proprietary one sometimes found in desktop computer models (as opposed to towers or mini towers). This form factor is characterized by an expansion board that runs parallel to the motherboard. A riser card arrangement is used for expansion cards thereby allowing for smaller cases. The disadvantage is that this limits the number of expansion cards available.

LPX motherboards are typically integrated and most have the video and sound components built-in. However, due in part to the fact that the form factor is non-standardized, the ATX form factor is more popular.

BTX

Balanced Technology Extended (BTX) form factor was released in 2003 by Intel. Unlike other form factors, this one did not evolve from an older form factor. Instead, it was a completely new form factor.

As shown in Figure C, the BTX form factor allows for more integrated onboard components because it is larger than ATX. The airflow path is optimized by moving the memory slots and expansion slots. This allows the main system board components to use the same airflow thereby requiring fewer fans and reducing noise.

Figure C

Balanced Technology Extended (BTX) form factor was released in 2003 by Intel.

The three motherboards included in the BTX form factor are outlined below.

• PicoBTX - This is the smallest BTX motherboard form factor. It uses four mounting holes and one expansion slot.

• microBTX - This form factor is slightly smaller than the regular BTX but larger than the PicoBTX. It uses seven mounting holes and four expansion slots.

• BTX - Also referred to as regularBTX, is the largest BTX form factor. It uses up to ten mounting holes and supports a maximum of seven expansion slots.

NLX

NLX has been a form factor in use with desktops for quite some time. It is a compact form factor, often referred to as a "low-profile application". NLX motherboards are easily distinguished by the riser card to which the expansion cards connect. The riser cards allow from two to four expansion cards to be plugged in. These expansion cards sit parallel to the motherboard.

Servers with this form factor offer power that is similar to the larger traditional servers, but in the size of a VCR. The obvious benefit of the NLX form factor is that the bulk of a traditional server is reduced to a space-saving smaller server. Additionally, servers assembled in a rack mount case can be secured to a rack, which can itself be secured to the floor, providing better equipment safety.

Table A summarizes the form factors outlined above, including what they are typically used for and the maximum number of slots