2.1 Hardware & Communication (Remember Diagram)

Question 1

What is a register?

Answer 1

An area to store data

Question 2

What is the purpose of the Program Counter?

Answer 2

Stores the location of the next instruction.
When its time to load the next instruction, the content of the PC is loaded into the MAR.

Question 3

What is the purpose of the Current Instruction Register?

Answer 3

Holds the current instruction ready to be decoded and executed by the Control Unit.

Question 4

What is the purpose of the Memory Address Register?

Answer 4

Temporarily stores the address of the next instruction in main memory.
This is then passed along the address bus to RAM.

Question 5

What is the purpose of the Memory Data Register?

Answer 5

The contents of the data stored in the MAR is temporarily stored in the MDR.
Program instructions are then passed from main memory to the CPU.

Question 6

What is the purpose of the accumulator?

Answer 6

It temporarily stores the results of the calculations made by the ALU or any data to be processed.

Question 7

What occurs during the Fetch stage of the FDE cycle?

Answer 7

1. The PC stores the address of the next instruction and the value in the PC is incremented by 1 as instructions are held sequentially and it needs to point to the next one.
2. The address of the next instruction is then copied into the MAR.
3. The data stored at the address in the MAR is then copied into the MDR.
4. Once it is ready, the executable part of the instructions is copied into the CIR.

Question 8

What occurs during the Decode stage in the FDE cycle?

Answer 8

1. The instructions in the CIR are split into two parts: the address and the operation.
2. The address part is placed in the MAR and the data fetched is put in the MDR.

Question 9

What occurs during the execute stage in the FDE cycle?

Answer 9

1. The contents of both the MAR and MDR are sent to the central processor.
2. The ALU will keep referring back to where the data and instructions are stored while executing them.
3. The Control Unit will then follow the instructions that tell them where to fetch the data from. It will then read it and send the necessary signals to other parts of the computer.

Question 10

What are 2 advantages of the Von Neumann Architecture?

Answer 10

• Nearly all types of data can be processed with this architecture.
• It is cheaper than alternative methods of processing.

Question 11

What are 4 disadvantages of the Von Neumann Architecture?

Answer 11

• Can be slower than other methods
• Can be limited by the bus transfer rate
• Doesn’t always maximise the use of the CPU
• Poorly written programs result in data mixups as both programs use the same memory.

Question 12

What is RAM and what is it used for?

Answer 12

Random Access Memory holds programs and associated data when an application is running.
It also holds the operating system.

Question 13

What is Cache and what is it used for?

Answer 13

Cache is small, extremely fast memory located near the processor that holds intermediate data during processing.

It is much faster to access than RAM and also more expensive.

Question 14

What is stored in Cache memory?

Answer 14

Regularly used data and instructions are stored in cache.
When the cache is full, the least recently used data is discarded.

Question 15

What is Parallel Processing?

Answer 15

Two or more processors will work together to perform a single task.

The task is split into smaller sub tasks which are then executed simultaneously by all available processors.

Question 16

What are 2 advantages of Parallel Processing?

Answer 16

More instructions can be processed in a shorter time as they are processed simultaneously.

Tasks can be shared to reduce the load on individual processors and to avoid bottlenecks.

Question 17

What are 4 disadvantages of Parallel Processing?

Answer 17

• It is difficult to write programs for multi-core systems.
• Results from different processors need to be combined at the end of processing which adds to the complexity and time spent.
• Not all tasks can be split across multiple processors.
• Concurrency (Executing out of order) introduces new software bugs.

Question 18

What is Amdahl’s law?

Answer 18

Parallel processing time = Time using a single processor system x (Fraction of processing which is linear + Fraction which can be run in parallel/number of processors)

Question 19

What are 3 examples of input devices?

Answer 19

Microphone
Camera
On-Screen Keyboard

Question 20

What are 4 examples of output devices?

Answer 20

Monitors
Speakers
LEDs
Printer

Question 21

What are 3 examples of optical storage as well as a rating for their capacity, speed, portability and durability?

Answer 21

• CDs, DVDs and Blu-Ray Discs.
• Small capacity (Around 25GB for Blu-Ray)
• Slower than hard disk but faster than tape.
• It is fairly portable as it can easily fit into a bag.
• It is not very durable as it can be easily scratched.

Question 22

What are 3 examples of magnetic storage as well as a rating for their capacity, speed, portability and durability?

Answer 22

• Floppy Disks, Internal/External Hard Disks.
• Can store the largest amounts of data (Up to 4TB)
• Fairly portable but larger than a CD and USB.
• Fairly reliable as it can still be damaged if dropped or exposed to strong heat or magnetic fields.

Question 23

What are 3 examples of Solid State storage as well as a rating for their capacity, speed, portability and durability?

Answer 23

• USB Flash drives or Solid State Drives (Internal)
• It is very fast and it has no moving parts.
• It is very portable and if it is a USB, it can fit in a pocket.
• It is very durable as it isn’t affected by magnets or heat.

Question 24

What storage type is the most cost-efficient?

Answer 24

Although Hard Disk Drives are cheaper and typically more cost-effective, SSDs offer cost savings in the long run by offering greater productivity and lower energy usage.

Question 25

What is a network?

Answer 25

Consists of more than one device connected together to communicate and share resources

Question 26

What is a client-server structure?

Answer 26

Services such as file storage are made available on servers to which the clients will connect to in order to access it.

Question 27

What is a Peer-To-Peer structure?

Answer 27

Every computer has the same status as the others therefore no computer acts as a server.
The peers must work together to fulfill the required task.
Distributed processing is utilised which allows the workload to be shared.

Question 28

What is a networking protocol?

Answer 28

A set of rules that governs communication between computers.

Question 29

What is the HTTP protocol?

Answer 29

Hypertext Transfer Protocol - Controls the transmission of webpages.

Question 30

What is the FTP protocol?

Answer 30

File Transfer Protocol - Allows the transfer of files across the internet, typically used when uploading files to a web server.

Question 31

What is the SMTP protocol?

Answer 31

Simple Mail Transfer Protocol - Directs email messages from server to server over the internet.

Question 32

What are the TCP/IP protocols?

Answer 32

Transfer Control Protocol - As suite of protocols which controls how data is broken down for transmission from sender to receiver.

Question 33

What is the IMAP protocol?

Answer 33

Internet Message Access Protocol - Once SMTP has directed an email to a server, IMAP allows it to be uploaded/downloaded from a device.

Question 34

What is the DHCP protocol?

Answer 34

Dynamic Host Configuration Protocol - Ensures that each host has a unique IP address.

Question 35

What is the UDP protocol?

Answer 35

User Datagram Protocol - Sends data across the internet quickly as no checking takes place

Question 36

What is the RTSP protocol?

Answer 36

Real Time Streaming Protocol - Designed to handle occasional lost packets so only slight degradation in quality occurs.

Question 37

What is handshaking?

Answer 37

The process where two devices establish their readiness to communicate.