CISSE Foundation Level
Computing Systems glossary
Every term this guide defines, A to Z, each with the chapter that teaches it. Open it when a word in a question is unfamiliar, and test yourself on it in the last week: cover the definition and say it in one sentence.
14 terms from the free first chapter
A
- Accuracy
Produces error-free results provided the input data and instructions are themselves correct ("garbage in, garbage out").
Taught in Overview of computing systems
- Application software
Performs specific tasks for the end user: word processors, spreadsheets, accounting packages, browsers, and custom business systems (the kind of solution covered in the chapter on developing information systems).
Taught in Overview of computing systems
C
- Central Processing Unit (CPU)
The "brain" of the computer, made up of the Arithmetic and Logic Unit (ALU, performs calculations and comparisons), the Control Unit (CU, fetches, decodes and directs execution of instructions), and registers (very small, very fast storage holding the instruction and data currently in use).
Taught in Overview of computing systems
D
- Diligence
Performs the same operation repeatedly without fatigue or loss of consistency.
Taught in Overview of computing systems
I
- Input devices
Feed data and instructions into the system: keyboard, mouse, scanner, microphone, touchscreen, barcode/QR reader.
Taught in Overview of computing systems
M
- Motherboard
The main circuit board that physically connects and lets the CPU, memory, storage and peripherals communicate, via buses (data, address, control) and expansion slots/ports.
Taught in Overview of computing systems
O
- Output devices
Present processed results to the user: monitor, printer, speaker, projector.
Taught in Overview of computing systems
P
- Primary memory
Directly accessible to the CPU: RAM (Random Access Memory, volatile, holds the programs and data currently running) and ROM (Read Only Memory, non-volatile, holds firmware such as the BIOS/UEFI that starts the machine).
Taught in Overview of computing systems
S
- Secondary storage
Non-volatile storage for data and programs not currently in use: hard disk drives (HDD), solid-state drives (SSD), optical discs, and flash/USB drives; far larger and cheaper per byte than primary memory, but slower to access.
Taught in Overview of computing systems
- Speed
Processes millions of instructions per second, far beyond manual capability.
Taught in Overview of computing systems
- Storage
Retains vast quantities of data and instructions for later retrieval (the memory hierarchy, below).
Taught in Overview of computing systems
- System software
Manages the hardware itself and provides the platform other software runs on: the operating system (e.g. Windows, Linux, macOS, Android), device drivers, and utility programs.
Taught in Overview of computing systems
U
- Utility software
A supporting category, often bundled with the operating system, that keeps the system running well rather than doing user work directly: antivirus software, disk defragmenters/cleanup tools, file compression tools, and backup utilities.
Taught in Overview of computing systems
V
- Versatility
The same machine can process payroll, mark examinations, or route a phone call, depending only on which program is loaded.
Taught in Overview of computing systems
The full glossary adds every term from the other 8 chapters, A to Z, each with the chapter that teaches it.