Unit 2 Flashcards

1
Q

What 8 factors affect choice of hardware?

A
  • User experience (ease of use, performance, accessibility)
  • User needs
  • Compatibility
  • Cost
  • Efficiency
  • Implementation difficulty
  • Productivity
  • Security
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2
Q

What are the 3 main types of RAID?

A

RAID 0 - Faster write speeds, no loss protection. Data is split (striped) between multiple drives.
RAID 1 - Data is mirrored between drives (providing loss protection). No performance benefits that come with RAID 0. Requires more storage (depending on how many times the data is mirrored)
Raid 5 - At least 3 drives required. Data is striped like in RAID 0 so fast access times, but data is also mirrored to another drive. Takes longer to recover than RAID 1.

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3
Q

What does RAID stand for?

A

Redundant Array of Independent Disks

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4
Q

What are the 4 types of Operating System?

A

Real-time Operating System - Intended to serve programs that require fast response times. Process data as soon as it comes in.
Single-User Single-Task - Only one user can be active a time, and that user can only run one task at a time.
Single-User Multi-Tasking - Only user can be active at a time, but that user can run multiple tasks at a time.
Multi-User - Multiples users can be active at the same time and can run multiple tasks.

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5
Q

What’s the difference between Von Neumann architecture and Harvard architecture?

A

In Von Neumann, instructions and data are stored in the same memory. In Harvard, instructions and data are stored in separate memory.

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6
Q

What are the internal components of a CPU?

A

Control Unit - Fetches, Decodes and Executes instructions.
Arithmetic Logic Unit - Performs arithmetic (math) and logical decisions.
Registers - Small amounts of high-speed memory inside the CPU that store small amounts of data needed during processing.
Cache - Small amount of high-speed RAM inside the CPU. Stores commonly accessed data and instructions in order to speed up processing.

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7
Q

What are the 5 types of register?

A

Accumulator - Stores arithmetic/logic results.
Instruction Register - Stores the current instruction.
Memory Address Register - Stores the address of the memory location to be accessed.
Memory Data Register - Stores the data at the memory location in the MAR.
Program Counter - Stores the address of the next instruction to be executed.

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8
Q

What are the 4 types of computer system?

A

Multi-functional Devices - Provides multiple functions in one package. E.g. a printer that can also scan and copy.
Personal Computers - A general-purpose computer, designed to run applications. Not designed to be used by multiple users simultaneously.
Mobile Devices - A portable computing device (small enough to carry around). Most include a built-in screen to allow users to view output.
Server - Purpose is to serve data to other computers on a network (can be the internet). Typically used by multiple users simultaneously.

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9
Q

Magnetic Tape vs Hard Drives

A

Tape does not have random access and has slower read/write speeds. However, they remain stable for much longer. Tape should be used where data must be stored for a long period of time, but will not be accessed often.

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10
Q

Two examples of utility software

A

Disk Defragmenter - Moves data around to ensure that it is all in one continuous section. This makes access times faster.
Anti-Virus Software - Detects and prevents malware from infecting the system.

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11
Q

Three examples of application software

A

Word processors, web browsers, games

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12
Q

What are the three main principles of Open Source Software?

A

Transparency - Code is publicly viewable. Provides users with confidence that the program is safe.

Collaboration - Anyone can view/alter/improve the codebase. Results in the software being better tailored to the users, as the people contributing are the users.

Licensing - The rules that govern what the public can do with the program’s code. For example, if it can be used for commercial purposes and if credit must be provided.

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13
Q

Three examples of sensors for collecting data

A

Camera, Accelerometer, Wearables

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14
Q

What is an example of cluster computing?

A

folding@home, blockchain (e.g. MurraxCoin)

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15
Q

What is emulation?

A

Emulation is the process of simulating another device in order to run software that is only compatible with that device.

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16
Q

What is one use of emulation?

A

Play old console games. Old consoles had specifically designed CPUs. This means that games made for old consoles will not run on modern CPUs. To run old games, the computer must run a simulation of the entire old CPU and then run the code on that simulated CPU.

17
Q

What types of device is Harvard architecture typically used in and why?

A

Embedded Microcontrollers, Digital Signal Processors. This model is used because it is cheaper than having to design separate data and instruction memory and buses.

18
Q

What is the difference between RISC and CISC?

A

RISC - Reduced Instruction Set Computer
CISC - Complex Instruction Set Computer

In RISC, all instructions contain dedicated hardware circuits. This means that all instructions can be carried out in one cycle.

In CISC, more complicated instructions do not have dedicated hardware circuits. Instead, they are executed across multiple cycles using the other more simple instructions. This means instructions can take varied amount of time to complete.

RISC favours CPU simplicity over coding simplicity while CISC is the opposite.

19
Q

What is pipelining?

A

When multiple instructions are being executed at once. This is possible because an instruction uses multiple different circuits consecutively. This means that once a circuit is finished, another command can use it while the next circuit is in use.

20
Q

What is multithreading?

A

A process can be composed of multiple threads. Each thread runs concurrently, meaning that tasks do not have to wait for other tasks to finish.

21
Q

What may be changed in a server CPU compared to a desktop CPU?

A

Higher cores - Servers need to handle lots of tasks at once

More features - Servers may have specific features that are needed to aid in their task.

22
Q

How to represent a negative number using Two’s Complement?

A
  • Calculate the representation as a positive number.
  • Flip the bits
  • Add 1
23
Q

What is the difference between synchronous and asynchronous communication?

A

Synchronous is where data is sent with specific timings and the two systems are kept in time by a clock signal.

Asynchronous is where data is transmitted as soon as it is sent. It requires no timing/clock signal. A start and an end indicator surround the data so that the receiving signal knows where the data starts and ends.

24
Q

What are the pros and cons of synchronous communication?

A

Pros:
- Faster than asynchronous

Cons:

  • Complicated
  • Requires a clock signal
25
Q

What are the pros and cons of asynchronous communication?

A

Pros:

  • Simple
  • Cost-effective
  • Doesn’t need specific timings or two way communication.

Cons:
- More overhead for start/stop indicators.

26
Q

What is the difference between serial and parallel communication?

A

Serial only uses on data connection, while parallel uses multiple.

Serial is cheaper since fewer wires are needed and the terminators at the ends of the cable are simpler.

Parallel has higher bandwidth (since there are more connections) but is more expensive and has trouble at long distance due to signals arriving at different times across different wires.

27
Q

What is the difference between TCP and UDP?

A

TCP (Transmission Control Protocol) ensures that a packet will definitely reach its destination. If it fails, it will try again until it gets there.

UDP (User Datagram Protocol) prioritises speed over accuracy. There are no retries or acknowledgements. This is best used when most of the data arriving fast is more important than all of it arriving slowly. E.g. a live stream or a game server.

28
Q

How do parity bits work?

A

The parity bit is changed to ensure that the number of 1s or 0s is either even or odd at all times. If the data is received and this is not true, we know that one of the bits has been modified.

29
Q

How do checksums work?

A

A hash is generated from the data by the sender. This is then attached to the message.

The receiver re-calculates the hash on their end, if the two hashes do not match, we know the data must have been changed.

30
Q

State and define 3 transmission protocols

A

TCP/IP - Transmission Control Protocol/Internet Protocol - Ensures data is received but can be slow

UDP - Universal Datagram Protocol - Fast but data is not sure to be received.

HTTP - Hyper-Text Transfer Protocol - Transfers webpages.

31
Q

What does a block diagram need?

A
  • Function Name
  • ## Arrows indicating logic flow