Mastering OCR GCSE (9-1) Computer Science (J277) requires absolute precision in register roles, comparative evaluation of hardware characteristics, strict logic in range-validation code, and proper parameter handling in Paper 2 algorithms. This package details the exact evidence-based strategies, blueprint layout, and frequent examiner pitfalls to help students secure top-tier marks.
読了時間 3 分更新日: 2026年6月21日
試験の概要
試験数
2
満点
160
制限時間
3時間
出題形式
5
試験
時間
配点
問題数
配点比率
出題形式
Paper 1: Computer Systems
1時間 30分
80
19
50%
Short Answer & Conversions, Structured Explanations & Diagrams, Quality of Extended Response Essay
Paper 2: Computational Thinking, Algorithms and Programming
1時間 30分
80
20
50%
Short Answer & Program Logic MCQs, Structured Code & Circuit Drawing, Algorithm Writing & Scenario Solutions
評価段階
987654321
電卓の規定
A scientific or graphical calculator that meets JCQ regulations may be used (some GCSE Mathematics and Science papers are non-calculator). Graphical calculators must be set to exam mode; you must clear any stored programs, notes or data before the exam, and the calculator must not be able to retrieve stored text or formulae.
AO1: Demonstrate knowledge and understanding of the key concepts and principles of Computer Science. (35%)
AO2: Apply knowledge and understanding of key concepts and principles of Computer Science to solve problems, including in design and development. (40%)
AO3: Analyse, evaluate and make reasoned judgements, and design, program, evaluate and refine solutions. (25%)
過去問と採点基準にもとづいて作成（2022–2024）。
電卓プログラム
Table mode for roots & turning points
Scientific calculator (e.g. Casio fx-991 series)
目的: Tabulate \(y\) across a range of \(x\) to locate sign changes (roots) and approximate maxima/minima.
使う場面: Solving or sketching a function when you want to find where its graph crosses or turns.
手順
Enter the function in TABLE mode, set the start, end and step, then read where the sign of \(y\) changes or where it peaks.
試験での注意: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.
Statistics mode (mean, SD & regression)
Scientific calculator (e.g. Casio fx-991 series)
目的: Read the mean \(\bar{x}\) and standard deviation directly, and the gradient/intercept (and \(r\)) of a linear regression for bivariate data.
使う場面: Any data-handling, statistics, or required-practical analysis question.
手順
Enter the data in STAT mode (1-VAR or A+BX), then recall \(\bar{x}\), \(\sigma\) or the regression coefficients.
試験での注意: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.
Carry exact values with Ans & memory
Scientific calculator (e.g. Casio fx-991 series)
目的: Keep full-precision intermediate values to avoid rounding errors.
使う場面: Multi-step calculations where premature rounding loses the final accuracy mark.
手順
Use Ans, STO/RCL or the M+ memory to reuse the unrounded result of each step; round only the final answer.
試験での注意: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.
Equation solver — to CHECK your working
Scientific calculator (e.g. Casio fx-991 series)
目的: Use the built-in EQN/SOLVE mode to verify roots of quadratics or simultaneous equations you have already solved by algebra.
使う場面: As a check only, after solving by hand.
手順
Enter the coefficients in EQN mode (or use SOLVE) and confirm they match your worked solution.
試験での注意: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.
よくあるミス
1high影響する配点: 2Architecture of the CPU
Confusing the roles of Program Counter (PC) and Memory Address Register (MAR).
回避方法: PC holds the address of the next instruction to be fetched; MAR holds the memory address currently being read from or written to. Remember: PC points ahead, MAR points to the current address buffer.
2high影響する配点: 1Designing, creating and refining algorithms
Failing to label True/False or Yes/No paths on flowchart decision nodes.
回避方法: Every decision diamond must have exactly two output paths, and they must be clearly labelled 'True'/'False' or 'Yes'/'No' to receive flow lines marks.
3medium影響する配点: 2Wired and wireless networks, protocols and layers
Stating that adding more network devices 'decreases bandwidth' of the transmission medium.
回避方法: Explain that adding devices divides the available bandwidth among more nodes, or increases packet collisions/latency, but does not decrease the absolute bandwidth of the physical line.
4high影響する配点: 1Programming fundamentals
Omitting correct string delimiters (quotes) when comparing string variables in pseudocode or code.
回避方法: Ensure string literals are wrapped in quotation marks, e.g. writing direction == "left" rather than direction == left.
5high影響する配点: 4Designing, creating and refining algorithms
Updating line values incorrectly or skipping loop steps in variable trace tables, causing off-by-one errors.
回避方法: Trace code line-by-line systematically. Only update variables in the table when an assignment on that specific line number actually executes.
6medium影響する配点: 1Data types
Confusing 'casting' with general 'type conversion' when explicit casting terminology is requested.
回避方法: Use the precise term 'Casting' and use functions like int(), str(), or real() to show explicit variable data type coercion.
7medium影響する配点: 1Secondary storage
Giving generic secondary storage hardware names like 'USB' or 'Hard Drive'.
回避方法: Be precise with terms like 'USB Memory Stick' (or Flash Drive) and 'Magnetic Hard Disk Drive (HDD)' to meet specific marking criteria.
8high影響する配点: 2Ethical, legal, cultural and environmental impact
Using generic descriptors like 'fast' or 'cheap' without comparative qualifiers.
回避方法: Always use comparatives, such as 'faster transmission speeds' or 'lower cost per gigabyte' to secure descriptive marks.
9medium影響する配点: 2Data storage
Writing 'SELECT ALL' or 'SELECT *' in database queries when specific, target fields are requested.
回避方法: Write only the exact field parameters requested, separated by commas (e.g. SELECT StudentID, TeamName). Use '*' only when all fields are requested.
10high影響する配点: 2Defensive design
Using 'or' instead of 'and' when checking ranges in validation logic.
回避方法: Use logical 'and' to define continuous range bounds (e.g., if height >= 40 and height <= 180). Using 'or' makes the validation statement logically redundant.