The document explains the types of computer memory, differentiating between primary and auxiliary memory. Primary memory includes volatile RAM and non-volatile ROM, while auxiliary memory provides long-term storage. It also covers various types of ROM, including PROM, EPROM, and EEPROM, and their characteristics.

1. K.M.S. Sailaja Rani
Lecturer in Computer Science
Y.A. Govt. College for Women
Chirala
by

2. • Computer is an electronic device used to store
and retrieve data to perform a particular task.
• Here the term retrieve means to get it again

3. Computer Memory is an internal storage area in
the computer, in which data and Programs are
stored either temporarily or permanently .

4. • Also known as Main
Memory or internal
memory.
• It holds instructions
and data, When a
program is executed.
• Volatile In Nature
• It Is Expensive And
Limited Storage
Capacity
• Non-Portable
• Also known as Auxiliary
Memory or external
memory
• It holds data and
programs, that are not
currently in use and
provides long term
storage .
• Non-Volatile In Nature
• It Is Cheap And Stores
Voluminous Data
• Highly Portable
• Data Access is low When

5. Primary Memory Is The Only Type Of Memory, That Is
Directly Accessed by The CPU.
Memory usually refers to Random Access Memory (RAM),typically
DRAM.
Types Of Primary Memory Are:
1) Random Access Memory (RAM)
2) Read Only Memory (ROM)

6. •Random Access Memory is a
volatile storage area within the
computer that is typically used to
store data temporarily. So that it can
be promptly accessed by the
processor.
•The information stored in the RAM
is basically loaded from the
computers hard disk, and includes
data related to the operating system
and applications that are currently
being executed by the processor.
•RAM is considered random access
because any memory cell can be
directly accessed if its address is
known.
•Read only memory refers computer
memory chips containing permanent
or semi-permanent data which is
non-volatile .
•Most computers contain a small
amount of ROM that contains critical
programs such as the basic input and
output system(BIOS), which is used
to boot up the computer when it is
turned on.
•ROM s are read only .To update the
programs stored in them, the ROM
chip had to removed and physically
replaced by another that had new
version of the program. But in today
ROM chips updations are possible.

7. Holds data without an external
refresh as long as it Is powered.
Made up of D Flip-Flops, In which
memory cells Flip-Flop Between 0 & 1
without use of capacitors .
Occupies more space and expensive.
SRAM is faster and more reliable.
SRAM chips are used in cars, house
hold appliances and hand held
electronic devices.
Common type of memory used in
PC, workstations, servers.
Must be refreshed in a second to
hold it’s data contents.
It’s chip contain millions of memory
cells. Each cell is made up of
transistors and capacitors and contains
1 bit of information.
It is cheap and can hold 4 Times
more data than SRAM.

8. It is Also Called One Time Programmable PROM
And Can Be Written Or Programmed using A Special
Device Called A Prom Programmer.
It Is A Type Of Ram That Can Be erased And
Reprogrammed.
It Is Based on A Semi-Conductor Structure Similar
To The EPROM But Allows The Entire Or
Selected Contents To Be electrically Erased And
Re-Written Electrically , So That They Need Not
Be Removed From The Computer. The process of
Writing an EEPROM is also known as
FLASHING.
Rewritable ROM chips include PROM, EPROM,EEPROM