Dean's Office Official Model Question Paper

Answer:

• System Software: Low-level software that manages computer hardware and provides a platform for running applications (e.g., Windows 11, Linux kernel, device drivers).
• Application Software: End-user software designed to perform specific user-oriented tasks or business operations (e.g., Microsoft Excel, Google Chrome, tally ERP).

Answer: CPU Cache Memory: A high-speed SRAM buffer located on or near the processor chip that stores frequently accessed instructions and data, reducing memory latency by bridging the speed mismatch between the fast CPU and the slower main RAM.

Answer:

• IPv4: 32-bit numeric address expressed in dotted-decimal format (e.g., 192.168.1.1), providing approximately $4.3 \times 10^9$ unique addresses.
• IPv6: 128-bit hexadecimal address separated by colons (e.g., 2001:0db8:85a3::8a2e:0370:7334), providing approximately $3.4 \times 10^{38}$ addresses to eliminate IP exhaustion.

Answer: Cloud Computing: On-demand network access to a shared pool of configurable computing resources (servers, storage, applications) over the internet with pay-as-you-go pricing. Three Service Models:

1. Infrastructure as a Service (IaaS)
2. Platform as a Service (PaaS)
3. Software as a Service (SaaS)

Answer:

• Phishing: A social engineering attack where malicious actors impersonate legitimate institutions via deceptive emails or websites to trick victims into revealing sensitive credentials or financial details.
• Ransomware: Malicious software that encrypts user files and demands an extortion payment for the decryption key.

von Neumann Architecture and the Machine Instruction Cycle

1. Core Principles of von Neumann Architecture

The von Neumann architecture is characterized by:

• Stored-Program Concept: Program instructions and working data are stored together in the same read-write memory address space.
• Sequential Execution: Instructions are processed sequentially unless an explicit branching jump occurs.
• Single Memory Bus: A shared bus conveys both data and instructions between CPU and memory (leading to the ‘von Neumann bottleneck’).

2. Functional Hardware Components

1. Central Processing Unit (CPU):
   • Control Unit (CU): Directs the operations of the processor, retrieves instructions, coordinates data movements, and controls peripheral interfaces.
   • Arithmetic Logic Unit (ALU): Performs integer arithmetic (+, -, *, /) and logical decisions (AND, OR, NOT, comparisons).
   • Internal Registers: Ultra-fast storage units including Program Counter (PC), Memory Address Register (MAR), Memory Data Register (MDR), and Instruction Register (IR).
2. Main Memory (Primary Storage / RAM): Volatile semiconductor storage directly accessible by the CPU via address and data buses.
3. Input/Output Subsystem: Peripheral controllers interfacing disks, displays, networks, and keyboards.

3. The Instruction Execution Cycle

1. Fetch:
   • The address stored in the Program Counter (PC) is loaded into the MAR.
   • The CU reads memory contents at MAR into the MDR and transfers the instruction into the Instruction Register (IR).
   • The PC is incremented to point to the next instruction.
2. Decode:
   • The instruction decoder decodes the opcode in the IR to determine the operation and identifies required operand addresses.
3. Execute:
   • The CU signals the ALU to execute the arithmetic/logical operation or transfers data between registers and memory.
   • The result is written back to an accumulator register or memory location.

Comparison of OSI 7-Layer and TCP/IP Models

1. Structural Comparison

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2. Functional Analysis

1. Application Layer: Provides network services directly to end-user software applications. Formats, encrypts, and packages user commands.
2. Transport Layer: Ensures end-to-end process-to-process communication using port numbers (e.g., port 80 for HTTP, port 443 for HTTPS). TCP provides flow control (sliding window), error checking, sequencing, and congestion management.
3. Network / Internet Layer: Handles logical routing across intermediate routers using IP addresses. Determines the optimal path across internetworks.
4. Data Link / Network Access: Responsible for node-to-node framing, media access control (MAC), physical addressing, and local link error detection (CRC).

Database Normalization Principles (1NF, 2NF, 3NF)

1. Purpose of Normalization

Database normalization is the systematic process of organizing relational database tables to:

• Minimize data redundancy.
• Eliminate data anomalies: Insertion Anomaly, Update Anomaly, and Deletion Anomaly.
• Ensure data integrity and consistency.

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2. Normal Forms Explained

1. First Normal Form (1NF):

   • Rule: Each table cell must contain a single atomic (indivisible) value, and each record must be unique. No repeating groups or multi-valued attributes (e.g., multiple phone numbers in one field) are permitted.
   • Fix: Split multi-valued fields into separate rows or a child relation.

2. Second Normal Form (2NF):

   • Rule: Table must be in 1NF, and all non-key attributes must be fully functionally dependent on the primary key (eliminates partial dependency in composite keys).
   • Example: If primary key is (StudentID, CourseID), and attribute CourseName depends only on CourseID, this is a partial dependency.
   • Fix: Decompose into two tables: Enrollment(StudentID, CourseID) and Course(CourseID, CourseName).

3. Third Normal Form (3NF):

   • Rule: Table must be in 2NF, and there must be no transitive dependency (non-key attributes must depend only on the primary key, not on another non-key attribute: $X o Y o Z$).
   • Example: In Employee(EmpID, Name, DeptID, DeptName), DeptName depends on DeptID, which depends on EmpID.
   • Fix: Move DeptID and DeptName to a separate Department(DeptID, DeptName) table.

Enterprise Cybersecurity: Defense-in-Depth Strategy

1. Concept of Defense-in-Depth

• A strategic layered approach to information security where multiple redundant defensive controls are deployed throughout an organization’s IT infrastructure.
• If one security barrier fails or is compromised, subsequent layers prevent unauthorized access and protect core data assets.

2. Core Protective Layers

1. Perimeter Security (Firewalls & DMZ):
   • Next-Generation Firewalls (NGFW) inspect packet headers and deep application payloads (DPI), blocking unauthorized IP addresses and port scans.
   • Demilitarized Zones (DMZ) isolate public-facing web servers from internal corporate database intranets.
2. Detection & Prevention Systems (IDS / IPS):
   • Intrusion Detection System (IDS): Passively monitors network traffic for signature matches or anomalous deviations from normal baseline activity and alerts security operations centers (SOC).
   • Intrusion Prevention System (IPS): Actively sits inline and automatically drops malicious packets, resets connections, or bans rogue IPs in real time.
3. Endpoint & Host Security:
   • Endpoint Detection and Response (EDR) agents installed on laptops and servers detect zero-day malware, enforce disk encryption (BitLocker), and block rogue USB devices.
4. Identity and Access Management (IAM & MFA):
   • Multi-Factor Authentication (MFA) mandates at least two distinct authentication factors:
     • Knowledge: Something you know (Password / PIN)
     • Possession: Something you have (TOTP Authenticator app / Hardware token)
     • Inherence: Something you are (Biometrics / Fingerprint)
   • Eliminates over 99% of credential-stuffing and password-spraying attacks.

Comprehensive IT Case Solution: Sagarmatha Health Network

a) Infrastructure Comparison: On-Premises vs. Public Cloud

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b) Disaster Recovery (DR) Architecture (RPO < 15 min, RTO < 1 hr)

1. Definitions:
   • Recovery Point Objective (RPO): Maximum acceptable data loss period (15 minutes).
   • Recovery Time Objective (RTO): Maximum tolerable downtime before restoration (1 hour).
2. Architectural Blueprint (Warm Standby / Pilot Light in Cloud):
   • Database Replication: Implement Continuous Automated Database Replication (e.g., PostgreSQL streaming replication or Amazon Aurora Multi-Region Replica) with write-ahead logging (WAL). Changes are mirrored to an alternate cloud region in near-real-time (RPO < 2 minutes).
   • Snapshot Backups: Automated incremental volume snapshots scheduled every 15 minutes, stored in write-once-read-many (WORM) immutable cloud object storage (S3 Object Lock).
   • Automated Failover (RTO < 20 mins): Use Infrastructure-as-Code (Terraform) scripts and Route 53 DNS failover health checks. If the primary region becomes unresponsive, the secondary standby environment spins up compute pods automatically within 15-20 minutes.

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c) Ransomware Defense and Zero-Trust Security Framework

1. Network Segmentation & Zero Trust Architecture (ZTA):
   • Segment the clinical network using VLANs and micro-segmentation. Administrative clinic workstations (Pokhara) must have zero direct network route to central EHR database servers.
   • Clinical servers reside in private subnets with egress filtered via Cloud NAT; direct SSH/RDP from public IP is strictly disabled.
2. Endpoint Protection and Email Filtering:
   • Deploy cloud-managed Next-Gen Endpoint Detection and Response (EDR, e.g., CrowdStrike/SentinelOne) on every clinic laptop to kill unauthorized script executions and reverse malicious file encryption.
   • Implement advanced email sandboxing (anti-phishing AI filters) that inspects incoming attachments in a secure isolated virtual environment before delivery.
3. Strict Identity Access Management (IAM) and Least Privilege:
   • Mandatory Multi-Factor Authentication (MFA) via hardware security keys or authenticator apps for all doctor, nurse, and admin portal logins.
   • Role-Based Access Control (RBAC): Billing staff can access invoices but cannot read diagnostic MRI scans; doctors can access patient health records but cannot install executables.