Memory Capacity.

1.      Less Memory Capacity

For normal usage small capacity is enough.  You can use normal office packages and access internet & E-mail with a less memory.  You can even play a simple game using less memory.  Normally using small capacity of memory you can open one or two windows at a time.

2.      Medium Memory Capacity

To use latest versions of normal day today use software packages at lease medium capacity of memory would need.  If you have this you can open 4-5 windows at a time.  Handling small databases, small network and taking printouts from printer connected to several PCs is possible with medium capacity memory.

3.      Large Capacity Memory

To use publishing animation and web creating software like Corel Draw, Flash, Maya etc.  For complex games and workgroup which transfer big amount of data at a time also need a large Capacity of Memory.

01.2. Read Only Memory (RAM)

As the name implies these are read only memories.  Once data written into these cannot be changed.  But data written on this memory will not be deleted when power goes off.

Mask ROM

This is the basic type of ROM chip.  This is Program when producing.  At a time huge number of chips must be produced.

PROM (Programmable Read Only Memory)

These are programmed after the production.  But after programmed the data can’t be changed.

EPROM (Erasable Programmable Read Only Memory)

As the name implies, this can be programmable and erasable.  It’s easy to identify these chips. It has a small window (hole) on the chip covered by a transparent piece of glass.  From this window you can see the circuit inside the chip.  Erasing and Programming is done using this window.  Ultra Violet Raze is used for this purpose.

EEPROM (Electrically Erasable Programmable ROM)

EPROM and EEPROM differ from the way the programming and erasing process done.  For EEPROM Ultra Violet Raze is not used.  Instead of that High Voltage is used.  But EEPROM can be erased and programmed for limited number of times.  So that EEPROM cannot be used for RAM chips.  Other thing is even to erase 1bit of data whole chip has to be erased.

EROM (Electrically Alterable ROM)

This can be used same as RAM chips.  Special feature is, not like RAM these chips are non-volatile.  But less speed than RAM chips.

FLASH MEMORY

This is a new kind of EEPROM.  On this data can be erased and rewrite.  For this process voltage of a functioning computer can be used.  Special feature is these are non-volatile and the capacity also high.