Praxis Computer Science study plan

Convert values among binary, octal, decimal, and hexadecimal, and perform two's-complement addition and subtraction without a calculator.

Construct truth tables for multi-input Boolean expressions and simplify them using Boolean algebra identities and Karnaugh maps.

Diagram the fetch-decode-execute cycle, labeling the program counter, instruction register, ALU, and control unit at each step.

Compare the levels of the memory hierarchy (registers, cache, RAM, secondary storage) by latency, cost per byte, and volatility.

Explain how an operating system manages processes, threads, scheduling, and virtual memory, including paging and page faults.

Distinguish compilers from interpreters and trace a short source file through preprocessing, compilation, assembly, and linking.

Write working programs that declare variables of several data types and use operators, input, and output correctly.

Implement and hand-trace nested conditional and iterative control structures, recording variable state at each iteration.

Implement linear search and binary search, and state the precondition that makes binary search valid.

Implement at least three sorting algorithms and compare their best, average, and worst-case time and space complexity.

Classify code fragments by Big-O growth class and justify each classification with a counting argument.

Write and trace recursive functions, identifying the base case and recursive case for each.

Describe encapsulation, inheritance, and polymorphism and identify each in a short given class design.

Implement a stack, a queue, and a singly linked list, and justify when each beats a plain array.

Insert into and traverse a binary search tree in inorder, preorder, and postorder, and state the resulting ordering property.

Distinguish the relational model from non-relational stores, and define primary keys, foreign keys, and integrity constraints for a scenario.

Write SQL SELECT statements that use WHERE, ORDER BY, and at least one INNER JOIN.

Derive an entity-relationship diagram from a written scenario and convert it into relational tables with keys marked.

Normalize a denormalized table to third normal form and state the anomaly each step removes.

Write SQL using joins, aggregate functions, GROUP BY, HAVING, and a subquery, and predict each result set before running it.

Explain transactions, the ACID properties, and when an index speeds up a query.

Describe information retrieval fundamentals: inverted indexes, keyword versus Boolean search, and relevance ranking.

Map the functions of each OSI layer to the TCP/IP model and name a protocol operating at each layer.

Convert between binary, dotted-decimal, and CIDR notation, and compute the network address, broadcast address, and usable host range for a given block.

Contrast TCP and UDP, and explain the three-way handshake, port numbers, and flow control.

Trace a browser request end to end, naming the role of ARP, DNS, DHCP, TCP, TLS, and HTTP at each stage.

Distinguish the roles of hub, switch, router, and firewall, and describe basic wireless and WAN connectivity options.

Classify common attacks (malware, phishing, denial of service, SQL injection, man-in-the-middle) and match each to a specific defense.

Apply the confidentiality-integrity-availability triad and the principles of authentication, authorization, and least privilege to a scenario.

Distinguish symmetric encryption, asymmetric encryption, and hashing, and explain the role of digital certificates in TLS.

Evaluate ethical, legal, and social impacts of a computing system, including privacy, intellectual property, accessibility, and the digital divide.

Re-teach the three weakest subtopics identified by prior practice tests, working fresh problems in each until two consecutive correct attempts.

Complete two full-length timed practice tests under exam conditions, with no notes and strict timing.

Maintain a corrected error log that records the reasoning mistake, not just the right answer, for every missed item.

Consolidate all reference sheets into one final one-page formula and definition sheet for last-minute review.