HOur memories are just like a human brain. It is used to store data and instruction. Computer memory is the storage space in computer where the data is to be processed and instructions required for processing are stored. The memory is divided into 2 large number of small parts called cells. Its location or or Cell has a unique address which varies from zero to memory size-1 for example if computer has 64k words, then disease memory unit has 64 * 1024=65536 memory locations. The address of this memory is primary off three♥ types.
• Cach memory
• Primary memory / main memory
• Secondary memory
1.Cache memory type of computer memory
Cache memory is a very high speed semiconductor memory which can speed up CPU. It acts as a buffer between the CPU and main memory. It is used to hold those part of data and program which are most frequently used by CPU. The part of data and programs are are transferred from disk to catch memory buy operating system from where CPU can access them.
Advantages / Disadvantages
Advantage of cache memory are as follow :
• Cache memory is faster than main.
• It consumes less access time as compared to main memory.
• It stores the program that can be executed within a short period of time.
The disadvantages of cache memory are as follow :
• Cal has Limited capacity.
• It is very expensive.
2. Primary memory (main memory)
Primary memory holds only those data and instructions on which computer is currently working. It has Limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device. T h e s e memories are not as fast as resisters. The data and instruction required to to be processed reside in main memory. It is divided into two subcategories RAM and ROM.
Characteristics of main memory.
• These are semiconductor memories
• It is known as main memory.
• Usually volatile memory.
• Data is lost in case power is switched off.
• It is working memory of the computer.
• Faster than secondary memories.
• A computer cannot Run without primary memory.
3. secondary memory
This type of memory is also known as external memory or non volatile. It is lower than main memory. Dash are used for storing data information permanently. CPU directly does not access this memories instead they are accept via input output routines. Contents of secondary memories are first transferred to main memory and then CPU can access it . For example : Disk, CD -ROM,DVD,etc.
Characteristic of secondary memory.
• These are magnetic and optical memories.
• It is known as backup memory.
• It is non volatile memory.
• Data is permanently stored even is Power is switched off.
• It is used for storage of data in a computer.
• Computer may Run without secondary memory.
• Slower than primary memories.
Computer Random Access Memory.
lRAM ( Random Access Memory ) is the interna clicl]hŕ
memory of the CPU for storing data program and
program rresult.bst app for tradding Accountbst app for tradding Account It is read write memory which stores data until the machine is working. As soon as the machine is switched off data is erased.
Access time in RAM is dependent on the address that is each storage location inside the memory is a very easy to reach as other locations and text the same amount of time. Data in it is lost when we switch off the computer or if there is a a power failure. Hence a backup uninterruptible power system UPS is often used with computers.RAM is small both in terms of its physical size and in the amount of data it can hold.
RAM is of two types.n the the RAM can be accessed randomly but it is very expensive.
RAM is volatile, i.e , data stored i
• Static RAM ( SRAM)
• Dynamic RAM ( DRAM)
A).Static RAM ( SRAM)
The word static indicate that the memory retains its contents as long as power is being supplied. However data is lost when the power gets down due to volatile nature. SRAM chips use a matrix of 6 transistors and no capacitors. Transistors do not require power to prevent leakage so SRAM need not have to be refreshed on a regular basis. Because of the extra space in the matrix SRAM uses more chips than DRAM for the same amount of storage space thus making the manufacturing costs higher. So SRAM is used as a Cache memory and has very fast access.
Characteristics of static RAM.
• It has long life
• There is no need to refresh
• Used as a cache memory
• Large size
• High power consumption
B).Dynamic RAM ( DRAM )
DRAM, Unlike SRAM must continually refreshed in order to maintain the data. This is done by placing the memory on a reference circuit on a reference circuit that rewrite the data several hundreds time per SRAM used for more system memory because it is cheap and small. All DRAMs are made up of memory cells which are composed of one capacitor and one transistor.
Characteristics of the Dynamic RAM
• It has short data lifetime
• Need to be refreshed continuously
• Slower as compared to SRAM
• Used a RAM
• Lasser in Size
• Less expensive
• Less power consumption
Computer – Read only memory
ROM stands for read only memory. The memory from which we can only read but cannot write on it. this type of memory is non volatile. The information is stored permanently in such a memory during manufacture. A ROM stores such instructions that are required to start a computer. This operation is referred Tu as boot strap. ROM chips are not only used in the computer but also in other electronic items like washing machine and microwave oven.
A)MROM ( Masked ROM)
The very first ROMS were hard wired device contained a free program set of data or instructions this kind of ROM are known as ROMs which are expensive.
B) PROM ( programmable read only memory)
PROM DAY is read only memory that can be modified only once by a user. The user by a blank PROM and enters are desired content using a PROM program . inside the PROM chip there are small fuses which are burnt open during programming. It can be programmed only once and it is not erasable.
C) EPROM ( erasable and Programmable read only memory )
The EPROM can be erased by exposing it to ultraviolet light for a duration of up 40 minutes. Usually an EPROM Razer achieves this functions. During programming and electrical charge is is trapped in an inserted get region. The charge is retained for more than 10 years because the charge has no leakage path.
For erasing discharge ultraviolet light is passed through quartz crystal windows (lid) . This exposure to ultraviolet light dissipates the charge. During normal use the the quartz2 lead is sealed with a sticker.
EEPROM ( electrically erasable and Programmable read only memory)
The EEPROM is programmed and erased electrically full stop it can be erased and reprogrammed about ten thousand times. Both racing and programming take about 4 to 10 ms ( mile second ) in EEPROM, any location can be selectively raised and programmed. EEPROMs can be erased One byte at a time rather than erasing the entire chip. Hence the process of reprogramming is flexible but slow.
Advantage of ROM
• Non volatile in nature
• This cannot be accidentally changed
• Cheaper than RAMs
• Easy to test
• More reliable than RAMs
• These are Static and do not require refreshing
• Its contents are always no and can be verified
Geniun information Click here
The motherboard serves as a single platform to connect all of the parts of a computer together. A motherboard cannot CPU, memory, hhard drives, optical drives, video card ,sound card ,and other ports and expansion card directly or via cable. It can be considered as the backbone of a computer.
Features of motherboard
Motherboard comes with following features:
• Motherboard varies greatly in supporting various type of component.
• Normally a motherboard supports a single type of CPU and few type of memories
• Video card, hard disk, sound card ,have to be compatible with motherboard to function properly.
• Motherboards cases and power supplies must be compatible to work properly together.
• Intel  
• ASUS 
Description of motherboard.
The motherboard is mounted inside the case and age Security at age we are a small screws true-breeding light holes to stop motherboard contents ports to connect all of the internal component it provide a single socket of CPU for memory normally one of more slot are available motherboard provide port of attach floppy drive and hard drive at optical drives Bihari Banke bhils motherboard carries fans and special for design for power supply there is a peripheral card slot in front of the motherboard using which video cards sound cards and other expansion card can be connected to motherboard on the left side motherboards carry a number of ports to connect monitor, printer, Mouse ,keyboard, speaker and network cable motherboards also provide USB ports which Aloe compatible device to be connected in plug in plug / out fashion for example pen drive ,digital camera etc.
• The amount of data that can be stored in the storage unit.
• That in which storage capacity is expressed in term of Bytes.
Following are the main memory storage units:
1.Bit ( Binary Digit ) A binary digit is logical 0 and 1 representating a pasaive or an active state of a component in an electric circuit.
2.Nibble A group of 4 bits is called nibble.
3.Byte a group of 8 bytes is called byte. A byte is the smallest unit which can represent a data item or a character.
4. Word a computer word like a b is a group of fixed number of bytes processed as a unit which varies is from computer.
The length of a computer word is called word size or Word length and it may be as small as it bites or maybe as long as 96 bits. A com puter stores the information in the from of computer words.
Few higher storage units are following
Sr.no unit Description
1. Kilobyte ( kB ) 1KB = 1024 Bytes
2. Megabyte ( MB ) 1MB = 1024KB
3. GigaByte ( GB) 1GB = 1024 MB
4. TeraByte ( TB ) 1TB = 1024 GB