• Created by: g.zel11
  • Created on: 16-05-19 10:57
Purpose of ALU (arithmetic- logic unit)?
Responsible for carrying out calculations and logic operations. Acts as a conduit for input and output to and from the processor.
1 of 37
Purpose of the CU (control unit)?
Controls and coordinates the activities of the CPU directing the flow of data between the CPU and other devices. Manages the execution of machine code.
2 of 37
Purpose of memory unit?
Stores currently running programs, current files and the operating system
3 of 37
What are the 3 buses?
Control bus, Data bus, Address bus
4 of 37
Function of the control bus?
Carries control signals around the CPU, makes sure that the use of other buses by different components does not lead to conflict
5 of 37
Function of the data bus?
Provides a path for moving data and instructions between system components
6 of 37
Function of the address bus?
Transmits memory addresses of words that are used as operands in program instructions.
7 of 37
Name the registers.
Program counter, Memory address register, Memory data register, Current instruction register, Accumulator
8 of 37
Function of the program counter?
Always contains the address of the next instruction to be executed
9 of 37
Function of the memory address register?
Holds the address of the instruction or data to be fetched.
10 of 37
Function of the memory data register?
Temporarily stores fetched instructions/ data.
11 of 37
Function of the current instruction register?
Holds the instruction that is currently executed.
12 of 37
Purpose of the accumulator?
Used by an instruction that perform calculations
13 of 37
Describe the Fetch-Decode-Execute cycle.
Address of the instruction copied from PC to MAR. Instruction from the address is sent to MDR, PC increments. Contents of MDR are copied to CIR. Instruction at CIR is split into opcode and operand and decoded. It's then carried out on the operand.
14 of 37
What factors affect the processor performance?
Clock speed, Number of cores, Cache memory
15 of 37
What's the purpose of increasing clock speed?
Gives more cycles per second so more instructions can be executed per second and the program takes less time to run.
16 of 37
What's the purpose of adding extra cores?
The more cores, the more instructions can be run at the same time, so the processor performs faster.
17 of 37
What's the purpose of adding more cache memory?
More space for data / instructions in cache memory so RAM needs to be accessed less frequently. Accessing cache is quicker than accessing the RAM.
18 of 37
What is the purpose of pipelining?
Allows one instruction to be fetched as the previous one is being decoded and the one before that is being executed. (The FDE cycles overlap). Can be split into instruction pipeline and arithmetic pipeline.
19 of 37
Describe Von Neumann architecture.
Instructions are executed in a linear sequence. Uses single address bus and the same data bus to transfer both data and instructions. One instruction processed at a time.Uses fetch execute cycle. Program & data stored in the same format.
20 of 37
Describe Harvard architecture.
Instructions and data are held in separate memories. Parallel data and instruction buses may be used. Used in digital processing and embedded systems.
21 of 37
What is the contemporary architecture?
Combination of both von Neumann and Harvard architecture.
22 of 37
Describe array processor.
Single Instruction Multiple Data (SIMD). Allows same instruction to operate simultaneously on multiple data locations / many ALU's
23 of 37
Describe CISC (complex instruction set computers).
Longer instruction set to use as few lines of assembly language as possible. Uses many address modes. May have more registers and takes many cycles to complete one instruction.
24 of 37
Describe RISC (reduced instruction set computers).
Requires more RAM as only simple instructions, each taking one machine cycle can be executed. Many instructions must be used has fixed number of bytes.
25 of 37
Describe GPU (graphic processing unit)
A form of a co-processor designed specifically for graphics. Likely to have built in circuitry / instructions for common graphics operations. GPUs are able to perform an instruction on multiple pieces of data at one time.
26 of 37
Describe multicore system.
An architecture where processors have more than one core allowing multiple processes to be run concurrently.
27 of 37
Describe parallel system.
Made up of multiple processors in order to perform multiple operations concurrently. Code must be written in a way that the system can use the parallelism fully.
28 of 37
Describe input devices.
Pieces of hardware used to enter data into the computer, e.g barcode scanners, Camera- based readers, RFID
29 of 37
Describe output devices.
Output devices that take data produced by the computer and turn it into a form that humans can understand, e.g. LCD monitors. OLED monitors, printers, projectors, speakers.
30 of 37
Describe storage devices.
Non-volatile peripheral that stores data e.g. Cds, SSDs, HDDs.
31 of 37
Describe magnetic storage.
Works by magnetic patterns being read off platters that mechanically spin at high speeds. Can be noisy and susceptible to damage. Have a large capacity which makes them suitable for desktop purposes.
32 of 37
Describe optical storage.
Uses a laser to change the properties of the disks’ surface. Come in read-only (CD - ROM), recordable (CD-R) and rewritable format (CD- RW). Cheap and durable.
33 of 37
Describe flash storage.
Use memory chips. These can have their contents erased and subsequently overwritten when an electrical charge is applied. They have no moving parts and therefore tend to have lower power consumption . E.g. SSD
34 of 37
Describe RAM
Random access memory. Used to store programs currently in use. Volatile (contents lost when the computer is switched off)
35 of 37
Describe ROM
Read only memory. Used to hold data that needs to be in memory permanently e.g. BIOS bootstrap program. Non-volatile, small, uneditable.
36 of 37
Describe virtual storage.
Temporary usage of hard disk as an extension to memory. Used when RAM becomes full and can’t hold any more data.
37 of 37

Other cards in this set

Card 2


Purpose of the CU (control unit)?


Controls and coordinates the activities of the CPU directing the flow of data between the CPU and other devices. Manages the execution of machine code.

Card 3


Purpose of memory unit?


Preview of the front of card 3

Card 4


What are the 3 buses?


Preview of the front of card 4

Card 5


Function of the control bus?


Preview of the front of card 5
View more cards


No comments have yet been made

Similar Computing resources:

See all Computing resources »See all Fundamentals of computer systems resources »