Professional Knowledge
Professional Knowledge is the mains paper for the specialist post. For IT Officer it covers DBMS, networking, operating systems, data structures, programming, software engineering and information security; Law, HR, Marketing, Agriculture and Rajbhasha candidates answer in their own professional domain. The paper rewards exact definitions and applied reasoning rather than broad awareness.
Core rules
- DBMS: 1NF removes repeating groups; 2NF removes partial dependency on a composite key; 3NF removes transitive dependency; BCNF requires every determinant to be a candidate key. Know ACID properties and SQL clauses.
- Networking: learn the OSI seven layers and their devices; TCP is connection-oriented, UDP is connectionless; usable hosts in IPv4 = 2^h − 2, where h is the number of host bits.
- Operating systems: process states, scheduling (FCFS, SJF, round robin), the four deadlock conditions (mutual exclusion, hold and wait, no preemption, circular wait), and paging versus segmentation.
- Data structures: stack LIFO, queue FIFO, BST ordering, tree traversals, and the average/worst-case complexities of common sorts.
Worked example
Relation R(StudentID, CourseID, StudentName, CourseName), with StudentID → StudentName and CourseID → CourseName. Is R in 2NF? Reasoning: The primary key is the composite (StudentID, CourseID). StudentName depends only on StudentID, and CourseName only on CourseID; both are partial dependencies. Therefore R is in 1NF but not 2NF. Decompose into Student(StudentID, StudentName), Course(CourseID, CourseName) and Enrollment(StudentID, CourseID).
Traps
- Confusing 3NF with BCNF, or calling a partial dependency transitive.
- Forgetting to subtract 2 for network and broadcast addresses when counting usable hosts.
- Mixing devices across OSI layers, such as placing a router at the data-link layer.
- Negative marking applies here too: one-fourth of the marks for a wrong answer.