TCS Placement: Sample Questions 316 - 317 of 502

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Question 316

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Describe in Detail

Essay▾

Describe the Buddy system of memory allocation

Explanation

  • The buddy memory allocation technique is a memory allocation algorithm that devices memory into partitions to try to satisfy a memory request as suitably as possible.
  • This system makes use of splitting memory into halves to try to give a best-fit
  • Compared to the more complex memory allocation techniques that some modern operating systems use, buddy memory allocation is relatively easy to implement.
  • It supports limited but efficient splitting and coalescing of memory blocks.
  • Free memory is maintained in linked lists, each of equal sized blocks.
  • Any such block is of size .
  • When some memory is required by a process, the block size of next higher order is chosen, and broken into two.
  • Note that the two such pieces differ in address only in their bit. Such pieces are called buddies.
  • When any used block is freed, the OS checks to see if its buddy is also free.
  • If so, it is rejoined, and put into the original free-block linked-list.
Given the Image is Define the Buddy System Example

Question 317

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Describe in Detail

Essay▾

What are the important topologies for networks?

Explanation

BUS Topology

  • Bus is central cable that connects all devices on a local-area network also called the backbone.
  • Often used to describe the main network connections composing the Internet.
  • Relatively inexpensive and easy to install for small networks.
  • Ethernet systems use a bus topology.
    • Main Advantage: Easy to connect a computer or device and typically requires less cable than star topology.
    • Main Disadvantage: Entire network shuts down if there is a break in the bus.
Given the Image is Define the Bus Topology Consists of a Main Run of Cable with a Terminator at Each End

STAR Topology

  • Devices are connected to a central computer, called a hub.
  • Nodes communicate by passing data through the hub.
    • Main Advantage: One malfunctioning node does not affect the rest of the network.
    • Main disadvantage: Central computer is a single point of failure- upon its failure the entire network becomes unusable.
Given the Image is Define the Star Topology is Designed with Each Node Connected Directly to a Central Network Hub

RING Topology

  • A local-area network (LAN) whose topology is a ring- all of the nodes are connected in a closed loop.
  • Messages travel around the ring, with each node reading messages addressed to it.

    Main Advantage: It can span larger distances than other networks, such as bus networks, because each node regenerates messages as they pass through it.

Ring Topology

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