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Monday 6 August 2012

INTRODUCTION TO MEMORY :-




MEMORY:-




Introduction to computer memory:-

         

          Memory is just like the chip that can store data in both fashion i.e.in permanent and in temporary in other words it is just like a page of your note book from where you can retrieve the stored information. In simple word we can say that memory is just a storage unit.



Types of Memory:-

         

1.      Temporary Memory (RAM)

                  

          In this type of memory data can be store in temporary fashion. Temporary memory is also known as volatile memory. It means these types of memory stored data when Pc is in ON condition the whole data will be lost when Pc is in OFF condition or power is failure. Example of this type of memory is RAM i.e. (Random Access Memory)



Feature of RAM:-

1.                It is also also known as R/W memory.

2.                In RAM user can read, write and modify data.



Limitation:-

     It can lose data when Pc is in off condition.

2.      Permanent Memory (ROM)       

         

          In permanent memory data can stored in permanent fashion. It is also known as Non Volatile memory. It means in this types of memory data can be stored even PC in off condition or power failure. ROM is example of Permanent memory. ROM (Read Only Memory)

Feature of ROM:-

1.                It is also known as read only memory.

2.                In ROM user can only read the data write & modification operation is impossible or difficult in ROM.

3.                Because ROM is nonvolatile so data in ROM will be stay even PC is in OFF position.

3.      Semi permanent Memory:-

          Semi permanent memories store the data in semi permanent fashion. In semi permanent memory user can read, write modify & erase the data as well as data will be stay on there even Pc is in OFF condition. Example of semi permanent memory is HDD, FD, ZIP Disk, PEN Drive, Thumb Drive, etc.


Memory Organization:-


     
Memory Organization


Primary Memory

Secondary Memory

Temporary Memory / RAM

Permanent Memory / ROM



i)       Temporary Memory:-



          DRAM

          NON EDO

          EDO

          SDRAM

          DDRSDRAM

          DDR2SDRAM

          RDRAM

          SRAM

NVRAM

          VRAM



2ii)    Permanent Memory



          Masked ROM

          PROM

          EPROM

          EEPROM



3.                Secondary Memory:-

i)                  Magnetic

HDD

Floppy Disk

ZIP Disk

Tape Disk

VDO Cassette

ii)      Optical

Compact Disc

DVD



iii) Flash



          PEN Drive

          Thumb Drive

          SMC

MMC



Difference between Primary & Secondary Memory                        



Primary Memory
Secondary Memory

Primary memory has low access time i.e. 2.5 nano second.
Secondary memory has high access time i.e. 3.5 mille second.

Primary memory is fast.
Secondary memory is slow.

Primary memory stored small amount of data.
Secondary memory stored large amount of data.

Primary memory is costlier memory.
According to per megabyte cost
Secondary memory is cheaper than
Primary memory.

Primary memory is essential for computer system without it system can’t work.
Secondary memory is used for bulky data storage purpose without it system can work.


Difference between RAM & ROM



RAM
ROM
RAM is temporary memory.
Rom is permanent memory.
RAM is volatile nature i.e. it can wash out all data when power failure or Pc in OFF condition.
ROM is non volatile nature i.e. even Pc is OFF condition.
RAM has low access time i.e. 2.5 nano second.
ROM has high access time i.e. 3.0 nano second.
RAM is faster.
ROM is slower.
In RAM user can read, write and modify data on this memory.
In ROM user can only read data on this memory.

Difference between DRAM & SRAM



DRAM
SRAM
DRAM is a volatile nature.
SRAM is non-volatile nature.
In DRAM data is wash out when PC is in off condition or Power ‘s Failure
 In SRAM data will be staying on there even PC is in off condition or power’s failure.

DRAM is Cheaper.
SRAM is costlier.

The Capacitors and transistor are used to implement the memory cell in DRAM. 
The flip flop and registers is using to implements the memory cell in SRAM.

DRAM single capacitor and single
Transistor is used to stored single bit in DRAM.
6 TO 8 transistors are used to store single bit in SRAM.





DRAM CHIP Explanation



DRAM: - NON EDO, EDO, SDRAM, DDRRAM, DDR2RAM, DDR3 RAM, RDRAM.



1) Feature of NON EDO RAM:-

1. Introduce with PC XT Computer in 1981 by IBM used with INTEL8086, 8088, 80186, 80286 Mp based system.

2. NON EDO RAM has 30 contacts. (Silver Coated Contacts)

3. It has 8bit RAM.

4. Runs at 10 MHz of clock frequency.

5. NON EDO RAM available in SIMM (Single inline memory module)/ SIP Package.

6. This RAM is outdated.

7. Store up to 2MB data.



2) Feature of EDO RAM: - It is also known as Hyper page mode DRAM, EDO RAM starts the fetching the data from the next cell before the previous process complete.

1. Introduce with Pc AT by IBM in 1986 used with Intel 80386, 80486, PI, PII, and mP based system.

2. It has 72 contacts. (Silver coated)

3. EDO RAM was 32bit and also available in 64bit.

4. Runs at 25 MHz of clock frequency.

5. EDO RAM also available in SIMM & SIP package.

6. Store up to 64MB of data.

7. It is outdated.

3) Feature of SDRAM :-( Synchronies Dynamic Random Access Memory)

1.  Introduce with PC ATX  used with INTEL PII, PIII, Mp based system

 2. It had 168 contacts.(Gold coated)

3. SDRAM was 64 bit RAM.

4. Runs at 66 MHz up to 133 MHz of clock frequency.

5. SDRAM available in DIMM (Dual/Double inline memory module) / DIP (Double inline pins) package.

6. Stored up 128MB of data. (Single Chip)

7. Now it is outdated.



4) Feature of DDRRAM:-

1. DDRRAM stands for Double Data Rate Random Access Memory.

2. Used with PIV, mp based system and also with AMD’s mp (Athlon, sempron)

3. Introduced with PC ATX system.

4. It has 184 Contacts.

5. DDRRAM runs 233MHz, 266, 333, 400, 433, 533 MHz of clock frequency.

6. DDRRAM has 64 bits.

7. DDRRAM stored up to 2 GB of data.

8. DDRRAM available in DIMM, DIP, Package.

9. DDRRAM has golden-coated contacts.



 

Difference between SDRAM AND DDRRAM

SDRAM
DDRRAM
1. Passed data on single pulse that is on rising edge. 


Passed double data in single pulse i.e. on rising edge and falling edge.
2. It has two cuts

2 It has one cut


3. It can operate on 3.3 V
3. It can operate on 2.5V


4. It has 168 contacts
4 It has 184 Contacts



Feature of DDR2RAM: -



1.    It has 240 contacts.

2.    Runs on 667 MHz to 1067MHz.

3.    Introduce with PIVHT mP or laptop system also available in chipset 945 up to 965 chipset.

4.    DDR2RAM available in DIMM package.

5.     It can operate on low voltage 1.8v.

6.    Stored up to 2 GB of data.



Feature of RDRAM: -

1.    Introduce with PC ATX system.

2.    Used with server based computer or used with socket 423(Earlier Piv)

3.    Intel Xeon mP support RDRAM.

4.    It has 184 contacts.

5.    RDRAM available in RIMM package.

6.    Runs at 800MHz up to 1066MHz of clock frequency.

7.    Stored up to 2GB of data.



 Memory Module or RAM Packaging Style



                   Memory modules are slot that can provide the base for inserting RAM chip it can be available in different shape for e.g.



SIMM/SIP



1.    NON EDO and EDO

2.    SIMM packaging style available in white color.

3.    SIMM memory notch made up of steel.

4.    RAM can be inserted at 450 angles.



DIMM/DIP



1.    SDRAM and DDRRAM supported

2.    DIMM it can be available in black, blue, yellow color.

3.    Memory notch is made up of plastic.

4.    In this RAM is inserted at 900 angles.

RIMM

RDRAM





Troubleshooting in RAM (Troubleshooting is a technique that sort out the faults in system)



Symptoms: IF RAM is faulty than system can’t show the display on monitor



 How we trace out that RAM is faulty





Using two Methods we can easily trace out the faults in RAM

1.    BIOS Beep Code :  BIOS stands for Basic input Output system, it can perform the test of internal system components if it find any faults than it show the faults using beep code:

         IF your system show Continue long beep: Than your RAM is faulty

      Solution: Replace the RAM



2.    Debug card: It is debugging device that check the system status if it find any faults than it can display the faults using Hexadecimal code. It can be vary according your BIOS

If your RAM is faulty than Debug Card show the following Code

C0

C1

C2

C3

D0

D1

D2 etc with continue long beep



RAM Manufactures :-

Perx

Samsung

Ballmax

Samtronics

Corsair

Kingston etc.


















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