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Practical-1

Objective: To study the components of a motherboard.

Motherboard

The motherboard is one of the most important parts of the PC. A computer has many components, each

with their own roles and functions. The role of the motherboard is to allow all these components to

communicate with each other.

Fig 1.1 Mother board

Components of a motherboard:

Processor Socket:

The processor socket is the central piece of a motherboard, usually being located near the center of the

motherboard. It’s also the central piece because it holds the processor – the brain of your computer. socket

or CPU slot is a mechanical component(s) that provides mechanical and electrical connections between a

microprocessor and a printed circuit board (PCB). This allows the CPU to be replaced without soldering.

A CPU socket is made of plastic, a lever or latch, and metal contacts for each of the pins or lands on the

CPU. Many packages are keyed to ensure the proper insertion of the CPU. CPUs with a PGA (pin

gridarray) package are inserted into the socket and the latch is closed.

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Fig 1.2 Processor

Expansion Slots

Expansions have the role of letting you install additional components to enhance or expand the

functionality of your PC. You can install a TV tuner, a video capture card, a better soundcard, etc. – you

get the idea. These ports are located under the video card slot, and come in the form of PCI slots (on older

motherboards) or a scaled-down version of PCI-Express slots (on newer motherboards). Some

motherboards come with both types of expansion slots. The number of slots is usually dependent on the

format of the motherboard .

Fig 1.3 PCI slots

IDE and SATA Ports

IDE and SATA ports are used to provide connectivity for the storage devices and optical drives. The IDE

interface is somewhat outdated. It was replaced by the smaller and much faster SATA interface, which

currently reached its 3rd revision, being able to achieve maximum speeds of up to 600 MB/s, as opposed to

the IDE interface, which can reach a maximum of 133 MB/s.

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Fig 1.4 IDE slots

BIOS Chip and Battery

The BIOS chip contains the basic code needed to take your computer through the boot process, up to the

point where the operating system takes over. Since the BIOS code is stored on a memory chip that needs

constant power to function, a battery is also present to keep the chip powered when the computer is

unplugged.

Fig1.5 Battery

Northbridge and Southbridge

North Bridge: -The north bridge is an integrated circuit that is responsible for communications between

the CPU interface, AGP, and the memory. The north bridge is a single-chip that is north of the PCI bus

however, early computers may have had up to three separate chips that made up the north bridge. The north

bridge, which has a large heat sink attached to it. It gets hot because of the often very large amounts of data

traffic which pass through it. All around the north bridge you can see the devices it connects. The north

bridge and its immediate surround dings. A lot of traffic runs through the north bridge, hence the heat sink.

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FIG-1.6 (NORTH BRIDGE AND SOUTH BRIDGE)

South Bridge: - The south bridge is a chip that connects to other components inside computer through

bridge. The function of the south bridge is to send and receive computer data and controls input and output

devices. South bridge multitasks and performs all the functions. Southbridge is a reference to a chipset on a

PC motherboard. It is a group of microchips designed for a single function and manufactured as a single

unit.

Fig 1.7 North Bridge

Fig 1.8 South Bridge

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Practical – 2

Objective: To study the components of Switch Mode Power Supply

(SMPS).

Components of Switch Mode Power Supply:

Switch Mode Transistors and other Semiconductors:

A transistor is small and fast semiconductor used for amplification and voltage stabilization. Bipolar Power

Transistors (often BU or 2SC/2SD numbers)- High voltage power transistor, which is used as the main

switch Mode transistor.

Diodes and Rectifiers: AC line rectifier uses a combination of 2 or 4 diodes. High efficiency diodes are

used to rectify output voltages.

Capacitors (filter and bypass) in SWITCH MODE POWER SUPPLY (SMPS):

Filter Capacitors - Used to filter the rectified AC line input voltage and various outputs of the power supply.

Bypass Capacitors - These are green colored, high quality plastic dipped or rectangular molded capacitors

part of RFI filter. They are placed at output section and seldom fail.

Resistors: Test for proper value with the help of multi meter. While measuring the resistor in-circuit, if the

value is higher than normal value, then resistor is bad.

Fig 2.1 Components of SMPS

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Transformers and Inductors required in a SWITCH MODE POWER SUPPLY (SMPS)

High Frequency Transformers - They consist of the switch Mode power transformer and feedback

transformer. They provide line isolation and generate multiple output voltage. They rarely cause problems

and can be tested for open circuit. Some supplies use small Transformers for feedback instead of

optoisolators. Optoisolator is used to isolate the input line with the rest of the section.

Inductors - Output inductors rarely fail and they can be tested for open circuit. Replace the faulty inductor if

found.

Coupled Inductors - They are used as a part of Pi type RFI filter which is placed in the AC input circuit. The

windings of inductor are in series with AC line. They look like small transformer. They are very reliable and

help to reduce noise and spikes. They can be tested for open circuit.

Fig 2.2 Outer view of SMPS

.

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Practical – 3

Objective: To study the various ports and cables.

Computer Ports:

Computer ports are connection points or interfaces with other peripheral devices. There are two main types

of computer ports: physical and virtual.

Types of ports:

Physical ports are used for connecting a computer trough a cable and a socket to a peripheral device.

Physical computer ports list includes serial ports (DB9 socket ), USB ports ( USB 2.0 or 3.0 socket /

connector ), parallel ports ( DB25 socket / connector ), Ethernet / internet ports ( RJ45 socket / connector )

Virtual ports are data gates that allow software application (network) to use hardware resources without

any interfering. This computer ports ( network ports ) are defined by IANA ( Internet Assigned Numbers

Authority ) and are used by TCP ( Transmission Control Protocol ), UDP ( User Datagram Protocol ),

DCCP ( Datagram Congestion Control Protocol ) and SCTP ( Stream Control Transmission Protocol ).

Physical common computer ports:

USB port: USB port (Universal Serial Bus) created in mid-1990’s mainly to standardize

communications between computers and peripheral. Also USB ports can be used as a power

supply for different devices like digital cameras, microcontroller programmers, laptop coolers

and other. There were four types of USB computer ports: USB1.0 and 1.1 released between

1996 and 1998 with a speed range starting from 1.5 Mb up to 12 Mb ; USB 2.0 released in 2000

with a maximum speed of 480 Mb/sec and USB 3.0 released in 2008 with a maximum speed of

5 Gb/sec ;

Ethernet port: Ethernet/ internet ports were first introduced in 1980 to standardize the local

area networks (LAN). Internet ports use RJ45 connectors and have speeds between 10 Mb/sec,

100 Mb/sec and 1 Gb/sec, 40 Gb/sec and 100 Gb/sec ;

VGA port: VGA ports ( Video Graphics Array ) has 15 pins displayed on three rows and it is

mainly used for connecting the monitor with the video adapter from the computer motherboard;

adapters :

Serial port: Serial port uses the DB9 socket / connector and transfers information, one bit at a

time, between the computer and other peripherals. The serial computer port identifies with RS-

232 standard.

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Fig 3.1 Computer Ports

LAN card:

The LAN Card is a 'door' to the network from a computer. Any type of network activity requires a LAN

Card - the Internet, network printer, connecting computers together. Today many devices contain a

network card: Televisions for their Internet apps, Blu-ray players, mobile phones, VoIP desk phones, even

refrigerators. LAN Cards are hardware devices, which can be added to a computer or they can be

integrated into the main hardware of the computer.

Fig 3.2 LAN Card

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Practical – 4

Objective: To study the component of floppy disk.

Floppy Disk Drive: A floppy disk drive (FDD), or floppy drive, is a hardware device that reads data

storage information. It was invented in 1967 by a team at IBM and was one of the first types of hardware

storage that could read/write a portable device. FDDs are used for reading and writing on removable floppy

discs. Floppy disks are now outdated, and have been replaced by other storage devices such as USB.

Components of floppy disk drive:

Read/Write Heads: Located on both sides of a diskette, they move together on the same assembly. The

heads are not directly opposite each other in an effort to prevent interaction between write operations on

each of the two media surfaces. The same head is used for reading and writing, while a second, wider head

is used for erasing a track just prior to it being written. This allows the data to be written on a wider "clean

slate," without interfering with the analog data on an adjacent track.

Drive Motor: A very small spindle motor engages the metal hub at the center of the diskette, spinning it at

either 300 or 360 rotations per minute (RPM).

Stepper Motor: This motor makes a precise number of stepped revolutions to move the read/write head

assembly to the proper track position. The read/write head assembly is fastened to the stepper motor shaft.

Mechanical Frame: A system of levers that opens the little protective window on the diskette to allow the

read/write heads to touch the dual-sided diskette media. An external button allows the diskette to be ejected,

at which point the spring-loaded protective window on the diskette closes.

Fig 4.1 Floppy disk drive

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Circuit Board: Contains all of the electronics to handle the data read from or written to the diskette. It also

controls the stepper-motor control circuits used to move the read/write heads to each track, as well as the

movement of the read/write heads toward the diskette surface.

Fig 4.2 Components of floppy disk

Connectors:-On the back of the drive electronics circuit board at least two connectors. The 4pin, in-

line connectors Supplies power to the drive. The 34-pin edge connector provides control signals to

the drive and exchanges data between the drive and the disk controller in the computer.

Fig. 4.3 Connectors

.

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Practical – 5

Objective: To study the components of CD/DVD disk drive.

CD-ROM : The Computer CD drive is a precision device because the timing of sending the laser beam

and collecting the laser beam reflected from the CD must be precise. A misalignment in the structure or

working of any part of the CD drive will result in an error in reading the data from the CD.

CD drives can read any kind of computer data that has been written onto a CD.

Fig. 5.1 (CD-ROM)

Components of CD disk drives:

The CD drive consists of different parts that enable it to read data from the disc. The CD drive is a precision

device because the timing of sending the laser beam and collecting the laser beam reflected from the CD

must be precise

Optical Head:

The optical head of the CD-ROM drive consists of a read laser and an optical sensor. The read laser targets a

laser beam on the disc. The optical sensor collects the reflected laser beam from the disc.

Head Actuator:

The head actuator moves the optical head forwards and backwards from the center of the CD disk to the

outer end of the disc. This allows the optical head to access all the parts of the CD disk. The head actuator

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moves the optical head, away from the center of the CD disc, using very small intervals to follow the minute

tracks on the CD.

Fig. 5.2 (HEAD ACTUATOR)

Spindle Motor:

The spindle motor catches the CD when it is inserted in the CD drive and spins it. The circumference of the

CD at its center is less than the circumference CD at the outer edge.

Fig 5.3 (DISK DRIVE MOTOR)

Loading Mechanism:

The loading mechanism loads the CD in the Computer CD drive. The frequently used method for loading

the CD drive is the tray. The CD drive has an eject button that opens and closes the CD drive tray. The CD

is placed on the CD drive tray after opening it.

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Practical – 6

Objective: To study the components of hard disk drive.

Hard Disk Drive: Hard disk drive: abbreviated as HD or HDD, the hard drive is the computer's main

storage media device that permanently stores all data on the computer. The hard drive was first introduced

on September 13, 1956 and consists of one or more hard drive platters inside of air sealed casing..

Fig 6.1 Hard disk drive

Components of hard disk drive:

Disk Case - The rectangular shaped disk case holds all of the components of a hard

disk drive. The case is secured by screws and should not be opened outside of a

dust-free environment.

Disk Platter - The platter shaped like a record with a magnetic surface. Its job is to

store the data contained on the hard disk drive. There can be one or multiple platters

depending on the disk capacity.

Fig 6.2 (PLATTERS)

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Spindle - The spindle holds the platters together and the motor rotates the platters

at their designated speed, which is measured in RPM.

FIG 6.3 (SPINDLE)

Actuator - This is designed to move the read/write arm to the correct position on the

platter to read the data.

FIG 6.4 (ACTUTATOR ARM ASSEMBLY)

Read/Write Arm - The read/write arm contains many "heads" on the end of the arm

which are designed to float above the platter and read data from the platter

Fig 6.5 Read write head

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CONTROLLER: - The controller is a printed circuit board, mounted at the bottom of a disk

drive. It consists of a microprocessor, internal memory, circuitry, and firmware. The firmware

controls power to the spindle motor and the speed of the motor. It also manages communication

between the drive and the host. In addition, it controls the R/W operations by moving the actuator

arm and switching between different R/W heads, and performs optimization of data access.

FIG-6.6 CONTROLLER

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Practical – 7

Objective: To study the components of a keyboard.

Keyboard: A keyboard is one of the most important input devices of a computer. It lets you input the

commands and data that you want the computer to process. It is very simple to use and carry. It is one of the

simplest of computer components.

Fig. 7.1 (Keyboard)

Function of a keyboard:

The keyboard is used to type text and numbers into a word processor, text editor or other program. In a

modern computer, the interpretation of key presses is generally left to the software. A computer keyboard

distinguishes each physical key from every other and reports all key presses to the controlling software.

Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with

special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also

used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete

combination, which brings up a task window or shuts down the machine

Components of a keyboard:

The Outer Frame: The outer frame of a keyboard is mostly made of plastic. This keyboard houses

the key caps, the chips and internal circuits. Normally, there are 103 to 105 key caps etched on the

outer frame. On the right-hand top corner of many keyboards, there are three light-emitting diodes

(LEDs) that when lit show the activation of the command keys: Num Lock, Scroll Lock and Caps

Lock. The first one is for locking numbers, second one control scrolling and third one locks the text

output into uppercase letters.

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Key Switch and Plastic Sheets: As the name suggests, a key switch is small, dome-shaped switch

located under the key cap. These are now obsolete and rarely used in keyboards. Instead, sheets of

plastic with attached sensors are used. The sensors keep track of the key pressed and send the signal

to the keyboard processor.

Fig 7.2 Plastic sheet (Inside keyboard)

Key Cap: A key cap is the outer casing placed over the key switch and plastic sheet. It is generally

made of plastic. Each key cap is marked with paint that corresponds to different digits of the

keyboard. It is also the most damage-prone part of the keyboard and may need replacement from

time to time.

Fig. 7.3 (KEY CAP)

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Central Processor: Every key cap input is recorded by key switch or plastic sheet sensors. The

sensors pass the input to the central processor of the keyboard. The central processor of the keyboard

is the unit that controls all the activities going on inside the keyboard, and it sends the signal to the

computer's central processing unit (CPU). The CPU processes the input and relays it to the monitor

for display.

FIG 7.4 (CENTRAL PROCESSOR)

Table 7.1 Pin diagram of a keyboard:

Standard keyboard:

Standard alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm),

and have a key travel of at least 0.150 inches (3.81 mm). Desktop computer keyboards, such as the 101-key

US traditional keyboards or the 104-key Windows keyboards, include alphabetic

characters, punctuation symbols, numbers and a variety of function keys. The internationally common

102/105 key keyboards have a smaller left shift key and an additional key with some more symbols between

that and the letter to its right (usually Z or Y). Also the enter key is usually shaped differently. Computer

keyboards are similar to electric-typewriter keyboards but contain additional keys, such as the command or

Windows keys

Ergonomic keyboard:

Keyboard Pin out

PS2 Keyboard AT Keyboard

Pin Number Function Pin Number Function

1 Data 1 Clock

2 Reserved 2 Data

3 Ground 3 Reserved

4 5 volt 4 Ground

5 Clock 5 5 volt

6 Reserved 6 NC

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An ergonomic keyboard is a computer keyboard designed with ergonomic considerations to minimize

muscle strain and a host of related problems. Typically such keyboards for two-handed typists are

constructed in a V shape, to allow right and left hands to type at a slight angle more natural to the human

form.

Fig 7.5 Ergonomic keyboard

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Practical – 8

Objective: To study the components of a mouse.

Mouse: Mouse are a basic peripheral component of all modern desktop computers. Mice send data to your

computer that tells your computer where to display the cursor of your operating system's graphical user

interface. While mice come in a variety of shapes and sizes, their basic parts and functions remain similar.

Each mouse has at least one button for user input, a connection to the computer and a way to track motion.

Fig 8.1 Ball Mouse and Optical Mouse

Components of a mouse:

Buttons: The button or buttons of a mouse constitute part or the entire top surface of the mouse.

When you press a button, it tells your computer to perform an action at the cursor's location on the

screen. A mouse has at least one button, though most have two or more.

Motion Detection: Your computer needs to receive data about the motion and location of your

mouse. The two most common components for picking up this data are the trackball and the optical

sensor.

Scroll Wheel: Many mice have at least one wheel used to send scrolling data to the computer.

Standard mouse drivers interpret scrolling data according to the current window in your GUI.

Connections: Your mouse can't transmit data if it isn't connected to your computer. Some mice

connect to your computer via a cord, while others are cordless. If your mouse has a cord, it is likely a

USB cord that fits into your computer's USB port.

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Ball mouse:

Bill English created a ball mouse in 1972 while working for Xerox PARC.

The ball mouse replaced the external wheels with a single ball that could rotate in any direction. It came as

part of the hardware package of the Xerox Alto computer. Perpendicular chopper wheels housed inside the

mouse's body chopped beams of light on the way to light sensors, thus detecting in their turn the motion of

the ball.

Fig 8.2 Ball mouse

Optical mouse:

Optical mice make use of one or more light-emitting diodes (LEDs) and an imaging array of photodiodes to

detect movement relative to the underlying surface, rather than internal moving parts as does a mechanical

mouse. A laser mouse is an optical mouse that uses coherent (laser) light.

Fig 8.3 Optical Mouse

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Pin Name Description

1 DATA Key Data

2 n/c Not connected

3 GND ground

4 VCC Power , +5 VDC

5 CLK Clock

6 n/c Not connected

Table 8.1 Pin diagram of a mouse

Data: Mouse data packets or keyboard scan codes are sent from the mouse or keyboard to the computer on

this single wire serially.

Clock: This signal is sent from the mouse or keyboard to synchronize the data signal.

+5 VDC: This is a simple 5 volts signal for giving power to the mouse or keyboard.

Ground: This is a common ground signal used as a return path for data and is a reference to logical 0.

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Practical – 9

Objective: To study LAN cables & power cables of a computer system.

Straight and Cross LAN Cables:

Straight Cable: Straight cable is a term for a cable that uses the same standards on both ends of its wires,

could EIA / TIA 568A or EIA / TIA 568B on both ends of the cable. Simply put the sequence of colors on

both ends of the same. In straight cables, pin 1 at one end of the cable connected to pin 1 on the other end,

pin 2 connected to pin 2 at the other end, and so on.

Fig 9.1 Straight LAN Cables

Crossover cable: Crossover cable use the EIA / TIA 568A at one end of the cord and EIA / TIA 568B at the

other end of the cable. This cables are used for connecting same type of devices such as when you want to

connect two PC or two modems together then we use the Cross cables.

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Fig 9.2 Crossed cables

Hard Disk Drive cable:

It is a floppy cable with 64 little cables in it, with 40 pin holes, to connect to mother board and hard drive

and DVD. Black part connects to the motherboard grey part to hard disk and blue part to DVD.

Fig 9.3 HDD cable

Power cord:

A power cord, line cord, or mains cable is a cable that temporarily connects an appliance to the mains

electricity supply via a wall socket or extension cord. The terms are generally used for cables using a power

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plug to connect to a single-phase alternating current power source at the local line voltage—(generally 100

to 240 volts, depending on the location). The terms power cable, mains lead, flex or kettle lead is also used.

A lamp cord (also known as a zip cord) is a light-weight, ungrounded, single-insulated two-wire cord used

for small loads such as a table or floor lamp.

Fig 9.4 Power cord

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Practical – 10

Objective: TO ASSEMBLE A PC.

There are steps to assemble a PC. After finishing assembling all components, you will obtain the

computer for yourself and you can design a system more targeted toward your own use.

STEPS:-

STEP-1: Prepare the motherboard. Choose a good motherboard according to the type of use. If we want to

assemble the well-liked device, we should use Intel G31, GMA3100, or AMD 780 motherboard.

FIG 10.1(MOTHERBOARD)

STEP-2: Mount the CPU in the socket of the motherboard. You must choose the correct CPU for your

motherboard, and install it according to it instructions. Be careful not to install the CPU in wrong. Not only

would your computer not work, it could short-circuit and damage your motherboard.

FIG 10.2(INSTALLING CPU)

STEP-3: Connect the CPU cooler to the motherboard.

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FIG 10.3(PLACING OF FAN)

STEP-4: Attach the RAM (memory) modules in the corresponding slots. The motherboard should

have rows of slots that have 2 or 3 sections that are different lengths. Make sure the pins on the RAM

cards line up with the pins on the motherboard connector. Don't get the RAM slots mixed up with

PCI slots.

FIG 10.4(PLACING OF RAM SLOTS)

STEP-5: Open the case and mount the power supply which is M-ATX type. Make sure to connect all the

connections to the drives and the motherboard.

FIG 10.5 (PLACE POWER SUPPLY)

STEPS-6: Attach the Main board back plate to the case and check the Main board mounting positions.

The motherboard's instructions should tell the position of the motherboard.

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FIG 10.6

STEP-7: Suitably position the Main board in the case.

FIG 10.7

STEP8:- Mount the Hard disk and connect it to the power supply and the motherboard. There should be

separate connections for the power supply and the motherboard. In SATA Hard disk case, should remove the

jumper.

FIG 10.8

STEP-9: Connect the SATA connectors to the drives and the USB connectors and the case switches to the

motherboard. The case and motherboard's instructions should tell where to connect the cables.

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FIG 10.9

STEP-10: Connect the 20 or 24 pin ATX connector and the 4-pin power supply control connector to the

motherboard.

FIG 10.10

STEP-11: Mount the DVD-ROM drive. After connecting the ATA cable to the device, hook it up to the

power supply.

FIG 10.11

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STEP-12: Finally, select a compatible operating system, and follow the instructions to install. This way

the assembling of desktop is done and your complete desktop PC is ready to use.

FIG 10.12 OUTER VIEW OF CPU