4th Class Computers Science Characteristics of Memory Devices Access Modes

     Access Modes

Memories can be divided into different categories based on what memory cells can be accessed at a given instant.  

     The information from the memory can be accessed in the following ways:  

      Random Access Memory

Random Access indicates that locations in the memory can be accessed, that is, written or read, in any order regardless of the memory location that was accessed before. RAM, Floppy and hard disk are the examples of random access memories.

      Sequential Access

Sequentially Access is accessed by stepping through each memory location until the desired location is reached. In this mode, memory is accessed in predefined sequential order. Magnetic tape is an example of sequential mode.

      Direct Access

In some cases, data is accessed neither in a random fashion nor in a sequential fashion, but is a combination of both modes. A separate read/write head exists for a track and on a track, the information can be accessed sequentially. This type of semi-random mode exists in the magnetic disk. It is generally faster to access a RAM compared to SAM (Sequential Access Memory). Most of the electronics gadgets memories are of RAM type.  

 Fill in the blanks:

1. Sequentially Access is accessed by _____ through each memory location until the desired location is reached.

2. In the magnetic disk _______ type of mode exists.

3. ________indicates that locations in the memory that can be accessed, regardless of the memory location that was accessed before.

(A) Random access, Stepping, Random

(B) Directly, Direct, Sequentially access

(C) Stepping, Semi-random, Random access                

(D) Indirectly, Direct, Direct access

(E) Stepping, Fully-random, Direct access

Answer: (c)

Explanation

Correct Option:

(C) Options given in (C) are correct.

Incorrect Options:

(A) Options given in (A) are incorrect. Therefore, option (A) is incorrect.

(B) Options given in (B) are incorrect. Therefore, option (B) is incorrect.

(D) Options given in (D) are incorrect. Therefore, option (D) is incorrect.

(E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.    

 Match the following:

          A                                                                      B

1. Random Access                                            i.   Magnetic tape

2. Sequentially Access                                     ii.   Magnetic disk

3.   Direct Access                                              iii.   Hard disk

(A) 1, iii, 2, i, 3, ii                                               

(B) 1, i, 2, ii, 3, iii

(C) 1, iii, 2, ii, 3, i                                               

(D) 1, ii, 2, i, 3, iii

(E) 1, ii. 2, iii, 3, i  

Answer: (a)

Explanation

Correct Option:

(A) Option (A) is matched correctly.

Incorrect Options:

(B) Option (B) is matched incorrectly.

(C) Option (C) is matched incorrectly.

(D) Option (D) is matched incorrectly.

(E) Option (E) is matched incorrectly.