Mark Scheme: Unofficial Practice Paper: J277/01 Computer Systems

Series: Version ETotal Marks: 80
Strict OCR J277 Standard Marking Guide
Question Answer / Indicative Content Marks Guidance
1a
  • Program Counter: Yes
  • BIOS: No
  • MAR: Yes
  • Secondary Storage: No
  • Accumulator: Yes
  • MDR: Yes
4Von Neumann architecture
b
  • More cores allow parallel processing (1)
  • Multiple instructions executed simultaneously (1)
  • Increases total instructions per second (1)
3Number of cores
c
  • Stores frequently used instructions (1)
  • Faster access than RAM (1)
  • Reduces CPU wait time (1)
3Cache size
2a
  • Volatile (1)
  • Non-Volatile (1)
  • Fast (1)
3The difference between RAM and ROM
b
  • HDD/SSD used as RAM overflow (1)
  • Inactive data moved to disk (1)
  • Data swapped back when needed (1)
  • Allows more programs to run (1)
4Virtual memory
c
  • No moving parts / Robust if dropped (1)
  • Lighter / Smaller (1)
  • Lower power consumption (1)
3Solid state
3a
  • NIC (1)
  • Switch (1)
  • Transmission Media (1)
3The hardware needed to connect stand-alone computers into a Local Area Network
b
  • Central Switch (1)
  • 4 Workstations (1)
  • Direct links to switch (1)
  • No peripheral links (1)
4Star and Mesh
c
  • Connects different networks (1)
  • Reads IP addresses (1)
  • Routes packets along efficient paths (1)
3Routers
4a
  • Embedded is for specific task (1)
  • General is for multiple tasks (1)
  • Embedded has limited UI (1)
  • Camera module is embedded as it only manages photos (1)
4Examples of embedded systems
b
  • Peripheral: Manages drivers/buffers (3)
  • Defragmentation: Reorganises disk fragments to speed up access (3)
6Peripheral management
5a
  • MAC is physical/hardcoded (1)
  • IP is logical/dynamic (1)
  • MAC used within LAN (1)
  • IP used for internet routing (1)
4IP addressing and MAC
b
  • Splits data into packets (1)
  • Reassembles at destination (1)
  • Handles error checking (1)
3TCP/IP
c
  • (i) SMTP (1)
  • (ii) HTTPS (1)
  • (iii) IMAP (1)
3Common protocols including
6a
  • SQL code entered into web form (1)
  • Executed by back-end database (1)
  • Bypasses authentication (1)
3SQL injection
b
  • Fraudulent email sent (1)
  • Manipulates user to click link/provide info (1)
  • Theft of credentials (1)
3Social engineering
c
  • 4000 * 250 = 1,000,000 KB (1)
  • /1000 = 1,000 MB (1)
  • /1000 = 1 GB (1)
  • Correct final answer with units (1)
4Data capacity and calculation
7a
  • Data Protection Act 2018 (1)
  • General Data Protection Regulation (GDPR) (1)
2Data Protection Act
b
  • Level 3: Comprehensive discussion of all 3 areas (7-8 marks)
8Ethical issues / Environmental issues / Legal issues
8a
  • Manages central resources (1)
  • Handles authentication (1)
  • Responds to client requests (1)
3roles of computers in a client-server
b
  • Encryption scrambles data (2)
  • Firewall monitors/blocks traffic (2)
4Common prevention methods
c
  • Off-site security (1)
  • Automatic syncing (1)
  • Scalability (1)
3Cloud storage
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