ROM (READ ONLY MEMORY)

ROM (READ ONLY MEMORY)

As discussed in my early post on different types of memories here is about ROM READ ONLY MEMORY. it is also known as NON-VOLATILE MEMORY which simply means the data written in ROM is permanently written and cant be even washed away when the power is switched off. It is primarily used to store the programs used most frequently by the computer and various softwares of an OPERATING SYSTEM.

Usually the program and files stored in the ROM deals with interaction with hardware of the computer one such program is the BIOS( BASIC INPUT AND OUTPUT DEVICE). It is being used by the computer every time the computer is started. BOOTSTRAP LOADER is also located in this memory only.

Know as the memory is constantly evolved so if we cant alter or change the information in ROM than new memory cant be employed to use to overcome this program various types of ROM are there they can be summarized as:-

1.) MASKED ROM:-
It is the permanent ROM which is prepared by masking of sheets. Since it uses permanent storing technique so the data written in it once cant be alter later. Now a days it has completely been remove from the market and has got little use in machines which have to perform specific operation only.

2.) PROGRAMMABLE/ERASABLE ROM:-
This is a ROM in which the data can be re-programmed again and again because the information is stored in it in a semi-permanent way and it is prepared by placing specific fuses at points. Special techniques are used to change them and thus it can be re-program by the programmer.

3.) ELECTRICAL PROGRAMMABLE ROM:-
IT is almost same as that of above it differs only in the way that electric current is being used to alter the information.

4.) FLASH LIGHT TECHNIQUES:-
It is one the most recent and modern invention in which the laser beam is being focussed for a fraction of second on the chip in which the data has to been altered and it intensity and frequency is being controlled according to the desired use. It is faster and easier method but it is in developing phase and at present is costlier technique.