6 Memory Cards Used in Data Storage 4

                 

Memory cards are electronic flash memory storage devices for storing digital data. They are extensively used in mobile phones, laptops, camera and mp3 players. Here i an including different memory cards

    
1. Compact flash    

These type of memory cards are first made by Sandisc. The utilises flash memory technology. They are available as compact flash and compact flash 2. Their dimensions may be 46x36x3.3 mm or 46x36x5.5 mm                                

2. Memory stick  

    

These are memory card format manufactured by Sony. They are available in many versions. Memory quick pro has good data transfer rate and storage capacity. Memory quick duo and memory quick pro duo are also used.  

3. MMC      

                   

The multi media card is released by Seimens and Sandisc. They are based on NAND flash memory. They are available with a storage capacity upto 32 GB.                                 


4. Secure digital or SD.                       

          

These are released by Panasonic, Sandisc and Toshiba. They can store upto 2 GB of data. SDHC can store upto 32 GB.                                 

5. Mini SD                

   

They are memory cards used in mobile phones and cameras with very low form factor. With this case you will also get an adapter suitable for SD card slot.       

6. Micro SD            

    


It is a version of SD card used in mobile phones. It has a dimension of 15x11x1 mm. By using adapters it can be used in other memory card slots.

8 Upcoming Memory Techniques 0

1. Holo graphic data storage            

This technology gives high data storing capacity than magnetic and optical storage. These method stores data in same place with different angles of light. These can be read using same LASER with same angles of light. It has a data access time of about 200 milli seconds.
            
2. 3D optical data storage                        

This is a data storage technology in which we can read and write data in 3D resolution. Eventhough LASER is used, disc layers are more than common discs.          

3. TRAM                      

Thyristor RAM combines the high speed and volume of SRAM and DRAM. This utilises the electrical property called negative differential resistance. This thin capacitively coupled Thyristor can be used to manufacture memories of high density.                       

4. ZRAM                      

It is the short form of zero capacitor RAM. It is DRAM memory developed by Innovative silicon. Floating body effect of silicon on insulator is the base for this. This has the speed of 6 transistor SDRAM used in cache memories. AMD will use this technology in their future microprocessors.     

5. TTRAM                   

This is a memory technique similar to DRAM which is based on the concept of one transistor and one capacitor. It is the short form of twin transistor RAM. Here silicon on insulator is used instead of capacitor. Of the two transistors one acts as access transistor and other acts as storage transistor. 

6. FeRAM                    

It is also known as Ferro electric RAM. This method user Ferro electric layer instead of dielectric layer. It is a non volatile DRAM. It has high speed and high write/erase cycles. 

7. PMC                          

It is also called programable metallisation cell and is developed by combined effort of Arizona state university and Axon technologies. Long lifetime, memory density and low power consumption are the specialities of this technology.      

8. SONOS                    

It is a non volatile memory similar to flash memory. It is the short form of silicon oxide nitride  oxide silicon. In this technology silican nitried is used instead of polysilicon for storing charge.

6 common storage technologies 0

           
1. Semiconductor memory  
                 
These memories make use of IC's made up of semiconductor materials. It contains millions of transistors and capacitors. There are volatile and non volatile memories. ROM, magneto resistive RAM, flash memory etc are non volatile memories. SRAM and DRAM are the common volatile memories.  

2. Magnetic storage   

 

  

This is the method of storing data using various magnetisation patterns on magnetic materials. It is non volatile. Data are read and write using read god write head. Floppy disc and hard disc are disc shaped magnetic storage devices. Magnetic storage are also utilised in MICR of bank cheques and magnetic stripes in credit cards. Magneto resistive RAM is an advanced technique of magnetic storage. In this technique data are stored using tunnel magneto resistance.

3. Optical storage 
 

These are the most used storage technologies today. LASER is used to read and write data. Compact disc, DVD, Blue ray disc etc are the examples of optical storage.

4. Magneto optical.                         

In this method data are stored in magneto optical discs. They can be formated to special file system.  Operating system misunderstand these optical devices as hard disc.
                              
5. Optical tape         

Data are stored in long plastic tapes. They combines the technologies of both cinema film and optical disc. While a magnetic tape can store 10-50 GB, an optical tape can store upto 1TB.
                  
6. Phase change memory                       

The change in phase between crystaline and amorphous states by the action of heat is used in these types of memories. PCM, PRAM and CRAM are this type of memories.