A) Explain how the operating system manages computer memory. b) What are Artificial Neural Networks (ANNs) and what are their core applications in AI?

```
  1110
+ 1010
------
 11000
```
Therefore, $X_2 = 11000_2$.
$$
\boxed{X_2 = 11000_2}
$$

• b) Perform the binary operation $1010.11 + 111.10 - 101.11$:

```
  10010.01
-   101.11
----------
   1100.10
```
$$
\boxed{1100.10_2}
$$

• c) In a 7-bit coding scheme, letter N is represented by 1010010.

N is the 14th letter.

Since letters are assigned consecutive codes, and N (14th letter) is $82_{10}$, then A (1st letter) would be $82 - (14 - 1) = 82 - 13 = 69_{10}$.

$$
69_{10} = 64 + 4 + 1 = 2^6 + 2^2 + 2^0
$$
$$
= 1000101_2
$$
$$
\boxed{1000101_2}
$$

• d) Using 8-bit notation and 2's complement, perform $410 + (-710)$. The numbers 410 and $-710$ cannot be represented in 8-bit 2's complement notation. An 8-bit signed number using 2's complement can represent values from $-128$ to 127. Since 410 and $-710$ fall outside this range, the operation cannot be performed as specified with 8-bit notation.

• e) Differentiate between pure binary and BCD code:

  • Pure binary represents an entire decimal number as a single binary value. For example, $13_{10}$ is $1101_2$.
  • BCD (Binary Coded Decimal) represents each decimal digit of a number with its own 4-bit binary code. For example, $13_{10}$ in BCD is $0001 \ 0011_{BCD}$.

• c) (i) Two types of crimes the employee committed:

  • Unauthorized access: Gaining entry to the accounts office and payroll system without permission.
  • Data manipulation/Fraud: Altering salary data for personal financial gain.
  • Theft: Illegally obtaining money through fraudulent means.
  • (ii) Two recommendations to prevent such future occurrences:
    • Implement strong access controls: Use multi-factor authentication, role-based access, and regular review of user permissions for sensitive systems like payroll.
    • Establish audit trails and regular monitoring: Log all access and changes to sensitive data, and regularly review these logs for suspicious activity.
    • Segregation of duties: Ensure that no single employee has control over all aspects of a financial transaction (e.g., one person approves, another processes, and a third audits).

• f) Two possible causes of the scanner failure:

  • Incorrect or missing drivers: The necessary software (drivers) for the scanner might not be installed correctly or might be incompatible with the operating system.
  • Loose or faulty cable connection: The USB or power cable connecting the scanner to the computer or power source might be loose, damaged, or incorrectly plugged in.
  • Scanner not powered on: The scanner might not be switched on or might not be receiving power.

• g) Distinguish between disk compression and file compression:

  • Disk compression is a utility that compresses an entire hard drive or a partition, making all files stored on it take up less space. The operating system handles the compression and decompression automatically as files are accessed.
  • File compression involves compressing individual files or folders, typically to reduce their size for storage or transmission. This is often done manually by the user using specific software (e.g., WinZip, 7-Zip) and results in a new, compressed file (e.g., .zip, .rar).

• h) Two reasons for the hierarchical organization of data in a computer:

  • Improved organization and management: It allows data to be logically grouped into folders and subfolders, making it easier for users to locate, manage, and understand the relationships between different files.
  • Enhanced security and access control: Permissions can be set at different levels of the hierarchy (e.g., folder level), allowing administrators to control who can access, modify, or delete specific sets of data more efficiently.

16.

• a) The flowchart mentioned in the question is not visible in the provided image.