What is rom define its types?

Answer 1

ROM: Read Only Memory. Rom is memory that normally can only be read, but not written to.

Types of ROM:

1. ROM: Basic, hard-coded ROM that has its data implanted at the time of manufacture.

2. PROM- Programmable ROM: Usually is manufactured as blank ROM, and can be written to 1-time by 'burning' fuse links inside the device.

3. EPROM- Erasable Programmable ROM: A PROM device that can be erased through some means. This term is not generally used, as a more-specific method of erasing is usually part of the acronym (See EEPROM and MPROM below). A chip that can be erased by applying light to a window may use this term.

4. EEPROM- Electronically Erasable Programmable ROM: This indicates that the ROM device is erasable through an electronic signal, applied to an "Erase" input. When the correct logic signal (high or low depends on manufacture of the device), the device is "erased" back to it's default state.

5. MPROM- Magnetically Erasable Programmable ROM: This is similar to an EEPROM, except that the device is erased by exposing it to a magnetic field.

Another use of the term 'ROM' is CD-ROM (or DVD-ROM). This is a removable media format that is contained on an optical disk. As these discs can only be written to once, they are considered to be Read-only memory. (Note that "rewritable" disks exist...they are commonly designated as "CD-RW" and "DVD-RAM" or "DVD-RW") and would be similar to an EPROM in application.