Difference Between RAM And ROM

1. Name: Pratima Pal
Subject: RAM And ROM

2. What is RAM ?
 Random-access memory (RAM)
RAM chips came into the market in the early 1970s, with the first commercially
available DRAM chip, the intel 1103, introduced in October 1970.
RAM is a form of computer data storage which stores data and machine
code currently being used. A random-access memory device allows data items to
be read or written in almost the same amount of time irrespective of the physical
location of data inside the memory.
RAM devices often have multiple data lines and are said to be '8-bit' or '16-bit' etc.
RAM is normally associated with volatile types of memory

3. Types of RAM
The two widely used forms of modern RAM
1>static ram (SRAM)
In SRAM, a bit of data is stored using the state of a six transistor memory cell. This
form of RAM is more expensive to produce, but is generally faster and requires less
dynamic power than DRAM. In modern computers, SRAM is often used as cache
memory for the CPU.
2>dynamic ram(DRAM)
DRAM stores a bit of data using a transistor and capacitor pair, which together
comprise a DRAM cell. The capacitor holds a high or low charge (1 or 0, respectively),
and the transistor acts as a switch that lets the control circuitry on the chip read the
capacitor's state of charge or change it. As this form of memory is less expensive to
produce than static RAM, it is the predominant form of computer memory used in
modern computers.

4. Image of ram

5. What is ROM
 Read-only memory(ROM)
Read-only memory (ROM) is a type of non-volatile memory used in computers and
other electronic devices. Data stored in ROM can only be modified slowly, with
difficulty
Once data has been written into a ROM chip, it cannot be removed and can only be
read. ROM retains its contents even when the computer is turned off. ROM is referred
to as being non-volatile whereas RAM is volatile.

6. Types of ROM
There are different variations on the classic ROM chips which were manufacturer
produced and could not change.
 Programmable Read-Only Memory (PROM)
This type of ROM can be re-programmed by using a special device called a PROM
programmer. Generally, a PROM can only be changed/updated once.
 Erasable Programmable Read-Only Memory (EPROM)
This type of ROM can have its contents erased by ultraviolet light and then
reprogrammed by an RPROM programmer. This procedure can be carried out many
times; however, the constant erasing and rewriting will eventually render the chip
useless.

7.  Electrically Erasable Programmable Read-Only Memory (EEPROM)
This type of ROM works in a similar way to Flash memory in that it can its contents can
be 'flashed' for erasure ad then written to without having to remove the chip from its
environment. EEPROMs are used to store a computer system's BIOS (basic
input/output system), and can be updated without returning the unit to the factory. In
many cases, BIOS updates can be carried out by computer users wishing a BIOS
update.

8. Image of rom

9. What is the difference between ROM and RAM?
 A ROM chip is non-volatile storage and does not require a constant source of power to
retain information stored on it. When power is lost or turned off, a ROM chip will keep
the information stored on it. A RAM chip is volatile and requires a constant source of
power to retain information. When power is lost or turned off, a RAM chip will lose the
information stored on it.
 A ROM chip is used primarily in the start up process of a computer, whereas a RAM chip
is used in the normal operations of a computer after starting up and loading the
operating system.
 Writing data to a ROM chip is a slow process, whereas writing data to a RAM chip is a
faster process.
 A RAM chip can store multiple gigabytes (GB) of data, ranging from 1 GB to 256 GB per
chip. A ROM chip stores several megabytes (MB) of data, typically 4 MB or 8 MB per
chip.

10. Thank you