Heap Implementation of IStructures

1
Heap Implementation of I-Structures
EE-653 Project Professor Dr. Jean Luc
Gaudiot Daman Ahluwalia
2
Contents

• Heaps
• I-structure
• I-structures as Heaps
• Operations
• Advantages and Disadvantages
• Future Work

3
An Overview of Heaps

• Directed Acyclic Graphs
• Each Node is either a fork or a leaf
• Value is represented at leaf of the graph tree

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A 3x3 Array represented as a Heap
A
A11
A22
A21
A13
A12
A11
A31
A32
A33
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A 3x3 Array represented as a Heap
A
A
A11
A22
A21
A13
A12
A11
A31
A32
A33
A33
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Disadvantages of Heap Approach

• Large Start-up Overhead
• Sequentialization of array operations
• Centralization of array access
• Centralization of array
• Storage overhead

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An Overview of I-Structures

• Basically,it is a data structure with a presence
  bit associated with each element.
• Various states are Empty,Full or Deferred.

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An Overview of I-Structures contd.

• Presence DATA
• Two Changes is made to the this basic structure
• In addition to presence bit , LIST BIT is also
  introduced

Empty state, DATA unavailable Full state, DATA
available Deferred state, DATA unavailable
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An Overview of I-Structures contd.

• Also in Deferred state, data fields stores two
  pointers, Head_of_list and End_of_list.

Presence List Data
Empty state, DATA unavailable Full state, DATA
available, No Wait list Deferred state, DATA
unavailable Full state, DATA available, Wait List
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I-Structure As Heap
A
11
11
11
11
11
11
11
11
11
11
11
11
11
A11
A22
A21
A13
A12
A11
A31
A32
A33
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Operation
A
Process B Read(A11)
11
11
00
00
01
B
A11
12
Operation contd.
A
Process C Read(A11)
11
11
00
00
01
C
A11
13
Operation contd.
A
Process C Read(A33)
11
11
11
00
01
01
C
C
A33
A11
14
Operation contd.
A
Process D Write(A11)
11
11
11
00
11
01
C
C
A33
A11
15
Operation contd.
A
A
Process E Write(A11)
11
11
11
11
11
00
10
01
10
C
A11
A33
A33
A11
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Advantages and Disadvantages

• No Large Start-up Overhead
• No Race Condition
• No Deferred Writes
• Parallel Processing of Deferred Lists
• Temporal and Spatial Locality
• Fast

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Advantages and Disadvantages contd.

• Centralization of array
• Centralization of array access
• Storage overhead

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Future Work

• Investigate the effects of this new scheme
• Explore efficient method to reclaim the memory
  space