Bios Cmos Memory

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BIOS CMOS Memory

The BIOS settings that you use to control how your PC works must be saved in non-volatile memory so

that they are preserved even when the machine is off. This is as opposed to regular system memory,

which is cleared each time you turn off the PC. A special type of memory is used to store this

information, called CMOS memory, and a very small battery is used to trickle a small charge to it to make

sure that the data it holds is always preserved. These memories are very small, typically 64 bytes, and thebatteries that they use typically last for years. This non-volatile memory is sometimes called NVRAM .

CMOS stands for "Complementary Metal Oxide Semiconductor". This is one type of technology used to

make semiconductors (integrated circuits) such as processors, chipset chips, DRAM, etc. CMOS has the

advantage of requiring very little power, compared to some other semiconductor technologies. This is

why it was chosen for this use, so that the amount of power required from the battery would be minimal,

and the battery would be able to last a long time. This memory came to be called just "CMOS" since in

the early days most parts of the computer did not use CMOS. Ironically, with today's processors having to

do more and more and needing to do it with lower power consumption, they themselves are typically

made entirely with CMOS technology. However, "CMOS" by itself usually still refers to the BIOSsettings memory. Old habits die hard in the computer world.

The system uses something called a CMOS checksum as an error-detecting code. Each time you changethe BIOS settings, the checksum is generated by adding together all the bytes in the CMOS memory and

then storing the lowest byte of the sum. Then, each time the system booted, the system recomputes the

checksum and compares it to the stored value. If they are different, then the system knows that the CMOS

has been corrupted somehow and will warn you with an error, typically something like "CMOS

Checksum Error".

There are many different types of batteries used to power the CMOS; mostly, these have changed over

time as technology has evolved. These batteries are discussed here. You will not normally have to deal

with the CMOS memory directly; it holds the settings you enter in the BIOS setup program. Over time, it

is possible you will have CMOS problems; for example, you may find that the machine may begin to

forget its settings when it is booted. These are usually signs of trouble with the motherboard battery.

In addition to the standard CMOS memory used to hold system settings, Plug and Play BIOSes use an

additional non-volatile memory to hold extended system configuration data (ESCD). This is used to

record the resource configurations of system devices when Plug and Play is used.

The computer loads data from read-only memory (ROM) and performs a power-on self-test(POST) to make sure all the major components are functioning properly. As part of this test, thememory controller checks all of the memory addresses with a quick read/write operation toensure that there are no errors in the memory chips. Read/write means that data is written to a bitand then read from that bit.

The computer loads the basic input/output system (BIOS) from ROM. The BIOS provides the

most basic information about storage devices, boot sequence, security, Plug and Play (autodevice recognition) capability and a few other items.

The computer loads the operating system (OS) from the hard drive into the system's RAM.Generally, the critical parts of the operating system are maintained in RAM as long as thecomputer is on. This allows the CPU to have immediate access to the operating system, whichenhances the performance and functionality of the overall system.

When you open an application, it is loaded into RAM. To conserve RAM usage, manyapplications load only the essential parts of the program initially and then load other pieces asneeded.

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After an application is loaded, any fi les that are opened for use in that application are loaded intoRAM.

When you save a file and close the application, the file is written to the specified storage device,and then it and the application are purged from RAM.

In the list above, every time something is loaded or opened, it is placed into RAM. This simply

means that it has been put in the computer's temporary storage area so that the CPU can accessthat information more easily. The CPU requests the data it needs from RAM, processes it andwrites new data back to RAM in a continuous cycle. In most computers, this shuffling of databetween the CPU and RAM happens millions of times every second. When an application isclosed, it and any accompanying files are usually purged (deleted) from RAM to make room fornew data. If the changed files are not saved to a permanent storage device before being purged,they are lost

Upgrading Memory

1. The first step to upgrading the memory in your computer is to either restart the computer and enter the BIOS Setup

Utility or use the automated feature mentioned in the next paragraph. On the BIOS Main page, verify how many

memory slots are not populated. If all slots are populated, you must replace existing memory modules with memory

modules of the same type, but with more megabytes (MB).

2. Gateway has two automated methods on the Gateway Web site to assist in determining which kind of memory is

installed in your computer.

Memory Locator - Gateway makes it easy for you to locate the correct memory for your computer. The Gateway

Memory Locator feature offers Gateway Certified Memory upgrades specific to your serial number.

Serial Number entry - On the Support Home page, enter the serial number of the computer being upgraded. This

method searches our database for that computer's original configuration using the computer's serial number as a

reference point. As the information is retrieved, it is displayed in your browser and stored on your computer for

quick reference when you want to review it again.

3. On the configuration screen, look for the entry called "memory". The description gives the details on how much memory

and the type of memory that was originally installed in the computer. Memory modules used for upgrading need to

match the modules already installed in respect to the following categories except for size:

Size: Memory modules are listed by how much random access memory (RAM) is contained on the module.

Memory modules come in multiples of 16. The most common are 16 MB, 32 MB, 64 MB, 128 MB, 256 MB, and

512 MB. Refer to the product specifications on your computer's motherboard for maximum size of memory

modules that are supported.

Category: Memory modules are generally categorized as single-inline memory modules (SIMMs), dual-inline

memory modules (DIMMs), or Rambus dynamic RAM (RDRAM) interface memory modules (RIMMs). Sub-

categories of DIMMs are single data rate (SDRAM) and double data rate (DDR) memory modules. SIMMs and

DIMMs can be used as a single unit. RIMMs need to be used as a pair or in conjunction with a RIMM Continuity

Module (C-RIMM).

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Parity: The next item to know is whether the memory module in the computer is parity (ECC) or non-parity (non-

ECC). Most Gateway desktop computers use non-ECC memory.

Speed: Another item to know is the speed of the memory module. This information can be found either on the

configuration pages or on the Main page of the BIOS information. SIMMs normally have the speed annotated by

nanoseconds (ns) only. DIMMs and RIMMs have a rating like PC66, PC100, PC133, PC266, PC333, PC600,

PC800 or PC1066 with an optional secondary rating of nanoseconds.

Note: Do not mix memory speeds or install memory that has a faster rating than the motherboard. This will

stop the computer from starting, report less memory than you just installed, or cause errors in the

operating system. e.g. If you are using PC133 with undesired results, try PC100, etc.

Clock-cycles: The clock (4-clock, 2-clock) speed is vital in determining if the DIMM is compatible with the

motherboard. This information is generally available in the specifications of the memory module already installed in

the computer.

Technology: As products change, so does technology. Newer memory modules may be faster and have more

capacity than what is presently in your computer. The motherboard in your computer has to be compatible with the

technology that it is based on. Some memory modules are based on 64-bit and 128-bit technology, while others

are based on 256-bit technology. Refer to the specifications of your motherboard to ensure compatibility.

4. Placing the memory module on the motherboard is done by aligning the notches of the memory module with the

notches in the slots on the motherboard and pressing down until the latches rotate up to hold the module in place.

Note: Some desktop cases may need to have drives or cables temporarily removed for access to the memory slots.

Specific information on the procedure to install memory modules can be found in your computer's user guide.

Learn Computer Hardware Parts and their Functions

Learning computer hardware parts and computer hardware functions are really necessary for a

computer technician. This way, they can easily diagnose and troubleshoot a certain computer

hardware problem. Identifying computer hardware parts and computer hardware functions is not

that easy, you need to enroll in some training courses in order to learn these things. However,

with this article It can save you a lot of money.

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Computer Mother Board

The main computer hardware part is the mother board (MOBO) this is the main circuit board of

a computer. The motherboard has the connectors for joining additional boards. Normally, the

motherboard contains the CPU, BIOS, memory, mass storage interfaces, serial and parallel

ports, expansion slots, and all the controllers essential to power typical peripheral devices, such

as the display screen, keyboard, and disk drive. As a group, all these chips that exist on the

motherboard are well-known as the motherboard’s chipset.

BIOS and CMOS Battery

BIOS (Basic Input /Output System) – BIOS computer hardware function is to give orders for

the power-on self test (POST). This self test make sure that the computer has all of the required

parts and functionality required to effectively start itself, such as use of memory, a keyboard and

other parts. If errors are identified during the test, the BIOS instruct the computer to provide

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code that tells the problem. Error codes are normally a series of beeps heard shortly after

startup.

CMOS (Carbon metal –oxide –semiconductor) – is a technology for manufacturing integrated

circuits. CMOS technology is widely used in microprocessors, microcontrollers, static RAM, and

for some other digital logic circuits. Likewise CMOS technology used for a wide variety of analog

circuits such as image sensors, data converters, and highly integrated transceivers for several

form of communication. Frank Wanlass successfully patented CMOS in 1967 (US Patent

3,356,858).

CMOS Battery – Is a button type cell battery, computer hardware function of this parts is to give

power to CMOS so that the Bios setting is preserve when the PC is turn off.

Chipset

Chipset - Refers to a particular couple of chips on the motherboard; the NORTHBRIDGE and

the SOUTHBRIDGE. The Northbridge links the CPU to extremely high-speed devices,

particularly the core memory and graphics controllers. The Southbridge bonds to lower-speed

peripheral buses (such as PCI or ISA). In several recent chipsets, the Southbridge in fact

includes some on-chip integrated peripherals, such as Ethernet, USB, and audio devices. A

chipset is typically intended to work with a precise family of microprocessors. Since it controls

connections between the processor and exterior devices, the chipset plays a vital function insystem performance.



PGA (Pin grid array) ZIF TYPE SOCKET (Zero insertion force)

A CPU socket or CPU slot – is an electrical module that connects to a printed circuit board

(PCB) and is considered to house a CPU (also known as microprocessor).

CPU socket structure is basically reliant on the casing of the CPU it is designed to house. The

majority of the CPUs are based on the Pin Grid Array (PGA) architecture. Stiff pins are set in a

grid on the bottom of the processor are mated with holes in the socket. To reduce the danger of

bent pins, Zero Insertion Force (ZIF) sockets permit the processor to be place in without any

opposition and then lock in position with a lever or latch method.

Slot Type Processor Socket

SLOT TYPE – Slot type CPU slots are single-edged connectors alike to expansion slots, in

which a PCB holding a processor is slot in. Slotted CPU packages presented two advantages.



L2 cache memory size may perhaps package with the CPU fairly than the motherboard, and

processor insertion and removal was regularly easier. On the other hand, they confirmed to

have performance limitations and once it was probable to set larger cache memory straight on

the CPU die the industry reverted back to sockets.

Land Grid Array (LGA)

Land Grid Array (LGA) – packages in progress to replace PGA with mainly recent CPU

designs using this scheme. The name LGA “socket” is in fact a bit of a misnomer. With LGA

sockets, the socket has pins that build contact with pads or lands on the bottom of the processor

package.

TYPES OF MEMORY SLOT /SOCKET - Usually refers to the slot on a motherboard were the

memory modules (extended memory) are installed.



SIMM Memory Socket

Single-inline-memory module (SIMM) This slot has 72 pins.

DIMM Memory Socket

Dual-inline-memory modules (DIMM) slot.

Single Data Rate (SDR) this type of DIMM slot has 168 edge contacts.

DDR Memory Socket

Dual/Double Data Rate (DDR) DIMM slot has 184 edge contacts for (DDR 1)

Dual/Double Data Rate (DDR) DIMM slot has 240 edge contacts for (DDR 2 / 3)



SODIMM Memory Socket

SODIMM (SO-DIMM is short for Small Outline DIMM) Slot has 72-pin and 144-pin configuration.

SO-DIMMs are commonly utilized in laptop computers.

EXPANSION SLOTS

The Expansion slot is a kind of slot that appends an expansion bus (Adapter card), which

permits the processor to converse with peripheral attached to the adapter card. Data is sending

out to the memory or the processor it moves from the expansion slot via the expansion bus and

the system bus.

Industry Standard Architecture (ISA)

Industry Standard Architecture (ISA) SLOT



Is an 8 bit and 16 bit extensive bus, and runs at 4.77 MHz. The ISA bus was build up by a group

lead by Mark Dean at IBM as element of the IBM PC project in 1981. It starts off as an 8-bit

scheme and was extended in 1983 for the XT scheme architecture. The latest 16-bit standard,

the IBM AT bus, was launched in 1984.

Peripheral Component Interconnect (PCI)

Peripheral Component Interconnect (PCI) SLOT

Is a condition that describes a 32-bit data bus interfaces. PCI is a usual and extensively used by

expansion card manufacturers.

Accelerated Graphics Port (AGP)

Accelerated Graphics Port (AGP) SLOT



Known also as Advanced Graphics Port, habitually shortened to AGP is a high-speed point-to-

point channel for connecting a graphics card to a computer’s motherboard, mainly to support the

acceleration of 3D computer graphics. AGP controller is barely competent of controlling a

particular device.

Audio Modem Riser (AMR) SLOT –

Is a riser card that the computer hardware function is to

support sound or modem function.

Advance Communication Riser (ACR) SLOT – This type computer hardware parts is for

communication and audio subsystem. The slot hold up modem, audio, LAN, and Home Phone

line Networking Alliance (HPNA) or Home Networking cards.

Communications Network Riser (CNR) SLOT – This connector holds specifically planned

network, audio, or modem riser cards, major processing is ended through software and be in

command of the motherboard’s system chipset.

PCI Express Slot (PCI-E)

PCI Express (PCI –E) – is a computer expansion card interface layout introduced by Intel in

2004. This computer hardware parts was considered to substitute the universal use of PCI

expansion bus.

PCIe 1.1 (the most familiar version as of 2007) every lane carries 250 MB/s.

PCIe 2.0 twice over the bus standard’s bandwidth from 2.5 Gbit/s to 5 Gbit/s, meaning a

x32 connector can move data at up to 16 GB/s in every direction.

PCI Express 3.0 will take a bit rate of 8 GB transfers per second.



Integrated Drive Electronics (IDE)

Integrated Drive Electronics (IDE) CONTROLLER – Parallel ATA (PATA) is an interface set

for the connection of storage devices such as hard disks, solid-state drives, and CD-ROM drives

in computers. It utilizes the primary AT Attachment and AT Attachment Packet Interface

(ATA/ATAPI) standards.

Floppy Disk Drive (FDD)

Floppy Disk Drive (FDD) CONTROLLER – the computer hardware functions ofthis computer

hardware parts is to control your floppy disk drive to operate as designed.



Serial Advanced Technology Attachment (SATA)

Serial Advanced Technology Attachment (SATA) CONTROLLER – is a computer bus mainly

designed for transmits of data among a computer and storage devices (like hard disk drives or

optical drives).

SATA 1.5 Gbit/s

SATA 3.0 Gbit/s

SATA 6.0 Gbit/s

Power Supply Connector Terminal

POWER SUPPLY CONNECTOR TERMINAL



These connectors are intended for power supply, the power supply plugs are intended to fit to

these connectors in only one direction.

AT / ATX

Auxiliary power

FRONT PANEL CONNECTOR / SYSTEM PANEL CONNECTOR – These connector’s attaches

the switches and LED indicators.

Power switch (PWRSW) power-on the system unit

Reset switch (RESET) – Resets the system unit

Power / System LED – The system power LED lights up when system is powered up /

Power indicator

Hard disk drive LED (HDDLED) –The HDD LED lights up(Blinks) during harddisk activity.

Computer I/O Ports

INPUT/OUTPUT (I/O) PORTS – I/O Ports is a kind of interface where in external peripheral

attach to it can communicate with the system unit so the peripheral can drive data or accept

information from the computer. Examples of these peripherals are;

Keyboard / mouse

Monitors, projector

Printers, flatbed scanner

External storage devices, external modems

Headsets, microphones, game pads



Personal system 2 (PS2) PORT – is patterned on IBM Micro Channel Architecture, it is a 6-pin

connector. This kind of architecture transmits data through a 16-bit or 32-bit bus. Common

devices that are using these ports are;

Keyboard and Mouse

Line Printer Port (LPT)

Line Printer Port (LPT) or PARALLEL PORT – This is a 25-pin port that joined a parallel

printer, a flatbed scanner and used as a communication bond for null modem cables.

SERIAL PORT or COM PORT – is a logical gadget name used to assign the computer serial

ports. A 9-pin connector used by mouse, modems, and infrared unit can be linked to COM ports.

Universal Serial Bus (USB)



Universal Serial Bus (USB) PORT – A 4-pin serial cable bus that permits up to 127 plug-n-play

computer peripherals. This permits attaching or detaching of peripherals though the host is in

process. Supports synchronous and asynchronous transport types over the same rest of wires

up to 12Mbit/sec. USB 2.0 offers 40 times the transport rate judge against to USB 1.0 and

contend with the 1394 standard.

GAME/MIDI PORT – This computer hardware parts supports a Joystick or a Game Pad for

playing games, and MIDI Devices for playing or editing audio files.

LAN PORT – the computer hardware function of this device is for networking.

AUDIO/SOUND port – this computer hardware parts is used for sound output, Line inputs and

Microphone inputs.

Central Processing Unit (CPU)

Is a total calculation engine that is made-up in a single chip, understand and bring out the vital

information that controls a computer. Processors have a control unit and an arithmetic logic unit

(ALU), this two mechanism work as one to perform processing operations.

Dual Processors

Dual-processor (DP) – systems are those that enclose two split physical computer processors

in similar chassis. In dual-processor systems, the two processors can also be situated on the

same motherboard or on separate boards.

Dual-core configuration – an integrated circuit (IC) holds two entire computer processors.

Typically, the two matching processors are manufactured so they exist in side-by-side on the

same die, everyone has its individual course to the system front-side bus.



Dual core Processor features:

Hyper-Threading Technology – allows you to run numerous tough applications at the

same time.

Intel Extended Memory 64 Technology – offer elasticity for prospect applications that

support both 32-bit and 64-bit computing.

Dual-Core – Two physical cores in one processor support improved system reaction

and multi-tasking ability than a similar single core processor.

Processor core (An intel Core 2 Duo Chip) It has 291,000,000 transistor.

MEMORY MODULES

A computer hardware parts that are bring into play to pile up information or programs

(sequences of instructions) on a provisional or eternal basis for use in an electronic digital

computer.

Volatile memory is computer memory that requires power to maintain the stored

information.

Non-volatile memory is computer memory that can retain the stored information even

when not powered.

Types of memory module

SIMM Memory Module

1. SIMM (Single inline memory module) it has two types or model.

30 pin

72 pin



DIMM Memory Module

2. DIMM (Dual inline memory module) it has two classifications the SDR and DDR.

SDR (Single data rate)

DIMM Memory Module (DDR)

DDR (Dual/Double data rate)

1. DDR

2. DDR2

3. DDR3



SO-DIMM Memory Module

3. SO-DIMM (small outline dual in-line memory module) – SO-DIMMs are a smaller

option to a DIMM, being about half the dimension of standard DIMMs. Used in systems

which have space limitation such as notebooks.

72 Pin SODIMM

100 Pin Firmware SODIMM (32 bit data transfer rate)

144 Pin EDO SODIMM (64 bit data transfer rate)

DDR333 200-Pin SODIMM Memory (64 bit data transfer rate)

PC3200 DDR400 200-pin SODIMM (64 bit data transfer rate)

COMPUTER STORAGE DEVICES

Example of Storage Device (harddisk)



Storage device – is a computer hardware parts intended to store data. There are two kinds of

storage devices apply in computers; ‘primary storage’ device and ‘secondary storage’

device.

Storage Media – It is where the storage device records (write) and retrieves (read) the data,

instructions and information for future use. Examples of these devices are the following;

1. Floppy drive and Floppy disk

2. CD Drive / DVD drive and CD or DVD disc

3. Hard disk drive (PATA)

4. Hard disk drive (SATA)

COMPUTER EXPANSION CARDS

Is a printed circuit board (PCB) that can be slot in into an extension slot of a motherboard to add

extra functionality to a computer system. One edge of the extension card seizes the contacts

(the edge connector) that fit precisely into the slit. They begin the electrical contact among the

electronics (mostly integrated circuits) on the card and on the motherboard. The main reason of

an extension card is to give or expand the features not obtainable by a motherboard.

Video Graphic Card

Video Cards / VGA Cards – The video card is an extension card that permits the computer to

throw graphical information to a video display device such as a monitor or projector.



Sound Card

Sound Card – Is computer expansion cards that aid the input and output of audio signals to and

from a computer in manage of computer programs. Many computers include built in sound

capabilities, while others entail added expansion cards to give audio capability.

Network Interface Card (NIC)

Network Interface card (NIC) – A network interface card, generally referred to as NIC, is agadget that lets computers to be connected as one in a LAN, or local area network. Networked

computers correspond with each other by means of a certain protocol or agreed-upon language

for broadcasting data packets among the dissimilar machines, known as nodes.



MODEM Card

MODEM Short for modulator-demodulator – A modem is a gadget or program that enables a

computer to send out data over, for example, telephone or cable lines. Computer information is

stored digitally, while information send out over telephone lines is send out in the form of analog

waves. A modem change between these two forms.

SCSI Card

SCSI Card Short for small computer system interface – it’s a parallel interface, typical used

by Apple Macintosh computers, PCs, and lots of UNIX systems for joining secondary devices to

computers. Almost all Apple Macintosh computers, not including the earliest Macs and the

recent iMac, comes with a SCSI port for connecting devices such as disk drives and printers.

SCSI interfaces offer faster data communication rates (up to 80 Mb/s) than the ordinary serial



and parallel ports. As well as, you can join a lot of devices to a single SCSI port; therefore SCSI

is really an I/O bus rather than basically an interface.

COMPUTER INPUT DEVICES

Input devices are every hardware part that permits you to enter data and coaching into acomputer. Examples of these devices are;

Keyboard

Mouse

Image/Object scanner

Microphone

Joysticks, Game pads

PC video camera

Digital camera

Bar code scanner

Biometric scanner

COMPUTER OUTPUT DEVICES

Output devices are some hardware modules that communicate information to one or more

people. Examples of these devices are;

Monitor

Printer

Speaker

Projector

Documents

Bios Cmos Memory