Computer Fundamentals and Applications

(b) Performing routine inspections

Corrective maintenance is carried out after a fault occurs — it involves troubleshooting the fault, replacing failed components and repairing damaged hardware. Routine inspections are scheduled, preventive work done before any fault appears, so they belong to preventive maintenance, not corrective maintenance.

(b) Repeater

A repeater receives a weak signal, amplifies (boosts) it, and retransmits it so it can travel a longer distance without loss of quality. A modem converts signals for data transmission, a switch connects devices within a LAN, and a router forwards data between networks — none of them boost a weak signal.

(b) 32 bit

An IPv4 address is 32 bits long, written as four 8-bit octets separated by dots (e.g. 192.168.1.1).

(a) To convert private IP address to public IP address

NAT translates the private IP addresses used inside a local network into a public IP address (and back) so that many devices can share a single public IP for accessing the internet.

Generic Block Diagram of a Typical Computer System

          +----------------+                     +------------------+
          |   INPUT UNIT   |                     |   OUTPUT UNIT    |
          | Keyboard       |                     | Monitor          |
          | Mouse          |                     | Printer          |
          | Scanner        |                     | Speaker          |
          +--------+-------+                     +---------+--------+
                   |                                       ^
                   | Data / Instructions                   | Results
                   v                                       |
          +--------+---------------------------------------+--------+
          |                          CPU                              |
          |  +----------------+   +----------------+   +-----------+  |
          |  | Control Unit   |<->|      ALU       |<->| Registers |  |
          |  +----------------+   +----------------+   +-----------+  |
          +------------------------------+----------------------------+
                                         |
                                         | System Bus
                                         | (Data, Address, Control)
                                         v
          +-----------------------------------------------------------+
          |                        MEMORY UNIT                        |
          |  Primary Memory  : RAM, ROM                               |
          |  Secondary Memory: Hard Disk, SSD, Pen Drive, DVD         |
          +-----------------------------------------------------------+

Main units and functions:

• Input Unit: Accepts data and instructions from the user, e.g. keyboard, mouse, scanner.
• CPU (Central Processing Unit): Processes data and controls the whole system.
  • ALU: Performs arithmetic and logical operations.
  • Control Unit: Controls and coordinates all parts of the computer.
  • Registers: Very fast temporary storage inside the CPU.
• Memory Unit: Stores data, instructions and results.
  • Primary Memory: Directly accessible by CPU, e.g. RAM, ROM.
  • Secondary Memory: Permanent/auxiliary storage, e.g. hard disk, SSD, pen drive.
• Output Unit: Gives the processed result to the user, e.g. monitor, printer, speaker.
• System Bus: Connects CPU, memory and I/O units through data bus, address bus and control bus.