IGCSE Computer Science Paper 1 Crossword: 3.1 Computer Architecture (Modules 218–227)
Name:
Date:
Class:
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Crossword
Read each clue and write the matching term in the grid. Numbers in brackets show the letters in each word.
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9
Across
- 2. Memory Address Register: a CPU register that holds the address of the memory location about to be read from or written to. It holds an address, not data, and sends it along the address bus. (3)
- 4. A register in the CPU that holds the address of the next instruction to be fetched. It increments after each fetch and changes when the ______ jumps. Word 1 of: _______ _______ (PC) (7)
- 7. Word 2 of the term in 4 Across: _______ _______ (PC) (7)
- 8. Current Instruction Register: holds the instruction copied from the MDR while the control unit decodes it and the CPU executes it. It stores the instruction itself, not an address. (3)
- 9. A set of wires that carries ______ signals, such as read and write, from the ______ unit to other components so they work together. It carries signals, not data or addresses. Word 1 of: _______ bus (7)
Down
- 1. A set of wires that carries ______ and instructions in both directions between the CPU and RAM. It connects to the MDR. Word 1 of: ____ bus (4)
- 2. Memory Data Register: a CPU register that temporarily holds the data or instruction just fetched from RAM, or data about to be written to RAM. It holds data, not addresses. (3)
- 3. A very small, very fast storage location inside the CPU (not in RAM) that holds one item of data or one address, such as the PC, MAR, MDR, CIR or ACC. (8)
- 5. A one-way bus that carries the ______ of a memory location from the CPU (sent from the MAR) to RAM. It carries addresses, not data. Word 1 of: _______ bus (7)
- 6. A register in the CPU that holds data being worked on and the results of ALU calculations, storing intermediate results before they are saved back to memory or output. Word 1 of: ___________ (ACC) (11)
Answer Key
IGCSE Computer Science Paper 1 · Modules 218–227
1D
A
T
2M
A
3R
D
E
4P
R
O
G
R
5A
M
6A
I
D
C
S
D
7C
O
U
N
T
E
R
U
E
E
M
8C
I
R
S
U
S
L
A
T
9C
O
N
T
R
O
L
R
Across
2MAR — Memory Address Register: a CPU register that holds the address of the memory location about to be read from or written to. It holds an address, not data, and sends it along the address bus.
4PROGRAM — A register in the CPU that holds the address of the next instruction to be fetched. It increments after each fetch and changes when the ______ jumps. Word 1 of: _______ _______ (PC)
7COUNTER — Word 2 of the term in 4 Across: _______ _______ (PC)
8CIR — Current Instruction Register: holds the instruction copied from the MDR while the control unit decodes it and the CPU executes it. It stores the instruction itself, not an address.
9CONTROL — A set of wires that carries ______ signals, such as read and write, from the ______ unit to other components so they work together. It carries signals, not data or addresses. Word 1 of: _______ bus
Down
1DATA — A set of wires that carries ______ and instructions in both directions between the CPU and RAM. It connects to the MDR. Word 1 of: ____ bus
2MDR — Memory Data Register: a CPU register that temporarily holds the data or instruction just fetched from RAM, or data about to be written to RAM. It holds data, not addresses.
3REGISTER — A very small, very fast storage location inside the CPU (not in RAM) that holds one item of data or one address, such as the PC, MAR, MDR, CIR or ACC.
5ADDRESS — A one-way bus that carries the ______ of a memory location from the CPU (sent from the MAR) to RAM. It carries addresses, not data. Word 1 of: _______ bus
6ACCUMULATOR — A register in the CPU that holds data being worked on and the results of ALU calculations, storing intermediate results before they are saved back to memory or output. Word 1 of: ___________ (ACC)