i) Stack:

• Data structure with series of elements with its last element waiting for operation.
• Operation can be done only in LIFO mode
• It is used when an element is not directly accessed by index or pointer.
• An element can be pushed only at the top in the series of elements.
• Only one pointer used for pop (deleting) and push (inserting)
• Stack pointer SP increases or decreases after operation.
• Uses: • Pushing of variables and context on interrupt. • Retrieving popping the pushed data from the stack.

ii) Queue:

• Series of elements with a header element waiting for read operation called deletion operation.
• The operation can be done in FIFO mode.
• It is used when an element is not directly accessed by index or pointer but through FIFO.
• Element can be inserted only at the end in the series of elements.
• There are 2 pointers, one for deleting after operation and other for inserting. Both increase after operation.
• Uses: • Print buffer: Each character is printed in FIFO mode. • Frames on network: Each byte has to be sent as a FIFO. • Image frames in a sequence.

iii) Circular Queue:

• Queue is called a circular queue, when a pointer on reaching its limit *Qlimit, and returns to its starting value *Qstart.
• A bounded memory block is allotted to a queue such that its pointer on incrementing never exceeds the set limit and returns to start on increasing beyond limit.
• The data element is retrieved in the FIFO mode.
• There is no exception on exceeding the limit of memory block.

iv) Array:

v) List:

• Each element has pointer to next element.
• Only first element is identifiable and header identifies it.
• No other element is identifiable, therefore not accessed directly.
• By going through first element and consequently through other elements, an element can be read, read and deleted, added or replaced by another element.
• Uses: • A series of task which are active. Each task has pointer of next task. • Menu that points to a sub-menu.

vi) Pipe:

• It is a device, which uses device driver function.
• The insertions are from source end and deletions at sink-end.
• The deletions are at destination end like queue.
• Insertion source identity is different from destination identity.
• Source and destination are connected by some function pipe_connect().

vii) Table:

• It is a 2-D structure (matrix).
• A memory block is allocated.
• There is always a base pointer for table that points to first element in first row and first column.
• 2 indices: 1 column, 1 row.
• Any element can be retrieved using a 3 bit address containing table base, column index, row index.
• A look-up table is a 2-D structure having only rows and each row has a key. When this key is read, address data is traced.