GCSE Computer Science - paper 1
Q&A
1. Central Processing Unit (CPU) - answer-processes data and instructions by
following the:
2. FETCH- DECODE- EXECUTE cycle
3.
4. Control Unit (CU) - answer-¬ executes program instructions by following FDE
cycle
5. - controls data flow inside CPU to registers and outside CPU
6. - Overall control of CPU
7.
8. Program Counter (PC) - answer-holds memory address of the instruction for
each cycle
9.
10. cache - answer-¬ very fast memory but slower than registers.
11. - Stores regularly used data to access quickly.
12. - low capacity but expensive
13. - different levels (l1 quickest but lowest capacity)
14.
15. von neuman architecture - answer-data and instructions stored together in
memory
16.
17. Memory Address Register (MAR) - answer-holds the memory address about to
be used by the CPU, which can point to specific data or CPU instructions
18.
19. Memory Data Register (MDR) - answer-holds the data or instructions fetched
from memory or waiting to be written to memory
20.
,21. Arithmetic Logic Unit (ALU) - answer-¬ carries out calculations and logical
operations.
22. - contains accumulator which is used to store intermediate results and
calculations
23.
24. clock speed - answer-¬ the speed at which instructions are executed in cycles
per second.
25. - measured in hertz
26. - 500MHz = 500 mill instructions
27. - 3GHz = 3 bill instructions
28.
29. embedded systems - answer-computers built into a larger system that perform
specific tasks with one circuit board
30.
31. accumulator - answer-intermediate results of logic and arithmetic results are
stored
32.
33. core - answer-¬ process data independently
34. - more cores = instructions processed faster
35.
36. Random Access Memory (RAM) - answer-¬ main memory
37. - volatile (loses data when off)
38. - more RAM = better performance
39. - stores: applications, GUI, OS
40.
41. Read Only Memory (ROM) - answer-¬ CPU reads instructions from ROM
, 42. - non-volatile (keeps data when off)
43. - smaller capacity
44. - stores: BIOS
45.
46. Dynamic Random Access Memory (DRAM) - answer-used as main memory
47.
48. Static Random Access Memory (SRAM) - answer-¬ used for cache memory
49. - small capacity
50. - fast access
51.
52. virtual memory - answer-¬ memory temporarily created on storage drive
53. - used when RAM is full
54.
55. Fetch-Decode-Execute cycle (fetch) - answer-1# copy memory address from PC
to MAR
56. 2# copy instructions stored in MAR to MDR
57. 3# increment PC to point to address for next instruction
58.
59. Fetch-Decode-Execute cycle (decode) - answer-4# instruction in MDR decoded
by CPU
60.
61. Fetch-Decode-Execute cycle (execute) - answer-5#instruction performed
62. # load data, calculations, logic operations, halt program
Q&A
1. Central Processing Unit (CPU) - answer-processes data and instructions by
following the:
2. FETCH- DECODE- EXECUTE cycle
3.
4. Control Unit (CU) - answer-¬ executes program instructions by following FDE
cycle
5. - controls data flow inside CPU to registers and outside CPU
6. - Overall control of CPU
7.
8. Program Counter (PC) - answer-holds memory address of the instruction for
each cycle
9.
10. cache - answer-¬ very fast memory but slower than registers.
11. - Stores regularly used data to access quickly.
12. - low capacity but expensive
13. - different levels (l1 quickest but lowest capacity)
14.
15. von neuman architecture - answer-data and instructions stored together in
memory
16.
17. Memory Address Register (MAR) - answer-holds the memory address about to
be used by the CPU, which can point to specific data or CPU instructions
18.
19. Memory Data Register (MDR) - answer-holds the data or instructions fetched
from memory or waiting to be written to memory
20.
,21. Arithmetic Logic Unit (ALU) - answer-¬ carries out calculations and logical
operations.
22. - contains accumulator which is used to store intermediate results and
calculations
23.
24. clock speed - answer-¬ the speed at which instructions are executed in cycles
per second.
25. - measured in hertz
26. - 500MHz = 500 mill instructions
27. - 3GHz = 3 bill instructions
28.
29. embedded systems - answer-computers built into a larger system that perform
specific tasks with one circuit board
30.
31. accumulator - answer-intermediate results of logic and arithmetic results are
stored
32.
33. core - answer-¬ process data independently
34. - more cores = instructions processed faster
35.
36. Random Access Memory (RAM) - answer-¬ main memory
37. - volatile (loses data when off)
38. - more RAM = better performance
39. - stores: applications, GUI, OS
40.
41. Read Only Memory (ROM) - answer-¬ CPU reads instructions from ROM
, 42. - non-volatile (keeps data when off)
43. - smaller capacity
44. - stores: BIOS
45.
46. Dynamic Random Access Memory (DRAM) - answer-used as main memory
47.
48. Static Random Access Memory (SRAM) - answer-¬ used for cache memory
49. - small capacity
50. - fast access
51.
52. virtual memory - answer-¬ memory temporarily created on storage drive
53. - used when RAM is full
54.
55. Fetch-Decode-Execute cycle (fetch) - answer-1# copy memory address from PC
to MAR
56. 2# copy instructions stored in MAR to MDR
57. 3# increment PC to point to address for next instruction
58.
59. Fetch-Decode-Execute cycle (decode) - answer-4# instruction in MDR decoded
by CPU
60.
61. Fetch-Decode-Execute cycle (execute) - answer-5#instruction performed
62. # load data, calculations, logic operations, halt program
