Associative and Auxiliary Memory

1. Computer Architecture
and Organization
Presentation

2. Auxiliary Memory
Associative Memory

3. Auxiliary Memory
 Auxiliary memory also known as auxiliary storage,
secondary storage, secondary memory or external
memory, is a non-volatile memory (does not lose stored
data when the device is powered down) that is not
directly accessible by the CPU, because it is not accessed
via the input/output channels (it is an external device). In
RAM devices (as flash memory) data can be directly
deleted or changed.

4. Forms
 The most common forms of auxiliary memory are
flash memory, optical discs, magnetic disks and
magnetic tape . The latest addition to the
auxiliary memory family is flash memory. This
form is much faster as compared to its
predecessors, as this form of auxiliary memory
does not involve any moving parts. In some
laptops, this type of auxiliary memory is referred
to as a solid state drive.

5. Storage
 It is used to store a large amount of data at lesser
cost per byte than primary memory; secondary
storage is two orders of magnitude less expensive
than primary storage

6. Examples
 USB
 Hard disk
The bottom surface of a compact disc, showing
characteristic iridescence.

7. Associative Memory
 A memory unit accessed by contents is called
associative memory.
 This type of memory is accessed by specific
address or location.

8. Contd…
 Associative memory is found on a computer hard
drive and used only in specific high-speed
searching applications. Most computer memory
known as random access memory, or RAM, works
through the computer user providing a memory
address and then the RAM will return whatever
data is stored at that memory address.

9. Contd…
 However, CAM works through the computer user
providing a data word and then searching
throughout the entire computer memory to see if
the word is there. If the computer finds the data
word then it offers a list of all of the storage
addresses where the word was found for the user.

11. Explanation of block diagram
 Block Diagram consists:-
 1)Argument Register.
 2)Key Register.
 3)Array & Logic of Computer.
 4)Match Register.
 When a word is written in a Associative Memory then no address, name, relative
position is given.
 Associative memory is also capable to find the unused or empty location to store
words. In Associative memory each cell has storage capability as well as logic
circuit.

12. Disadvantage
 CAM consumes excessive power.
 They cost several hundred dollars.
 They occupy a relatively large space.

13. Best ones.
 Associative memory computers are best for users
that require searches to take place quickly and
whose searches are critical for job performance
on the machine.