Main Focus Points Flashcards

(58 cards)

1
Q

What are the advantages of hexadecimal?

A

More compact representation.
Easier to understand.

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2
Q

What are the advantages of fixed point representation?

A

Faster processing
More accurate/ precise.

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3
Q

What are the advantages of floating point representation?

A

Can represent a larger range of numbers with the same number of bits.

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4
Q

What is the stored program concept?

A

Instructions are stored as data in main memory and the processors fetches and executes them sequentially.

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5
Q

What is sampling resolution?

A

How many different graduations of amplitude can be represented.

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6
Q

What are the advantages of normalisation?

A

More accurate representation for a given number of bits.
Unique representation of each number.

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7
Q

What is lossless compression?

A

When files are decompressed the original data is reproduced without any loss.

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8
Q

What makes up system software?

A

OS
Utility programs
Libraries
Translators.

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9
Q

What are utility programs?

A

Programs that perform specific tasks related to the running of the computer.
Security - antivirus software, firewalls
Disk organisation - defragmentation, free up disk space
System maintenance - managing files, compression

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10
Q

What is byte-code?

A

An intermediate step between source code and machine code, that allows for interpretation according to the architecture of the machine as and when it is required.

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11
Q

What is a register?

A

A small section of temporary storage apart of the processor, that store data or instructions during the FDE cycle.

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12
Q

What are the functions of the OS?

A

F - Organises files into directories.
U - Hides complexities of the hardware from the user
M - allocates cores to processors and manages the execution of multiple processes.
P - manages communication byeweeen processes and I/O devices.
Sn- manages updating software.

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13
Q

Advantage of assembly code?

A

More control over the final machine code executed.

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14
Q

What is fetch part of the FDE cycle?

A

PC holds the memory address of the next instruction to be fetched.
Memory address is loaded into MAR from the PC by the processor.
Processor sends the address to main memory via the address bus.
The contents of the memory address are loaded into the MBR by the data bus.
Contends of the MBR loaded into CIR by data bus.
PC incremented.

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15
Q

What is decode part of the FDE cycle?

A

Decode instruction is held by the CIR.
Control unit decodes the instruction by splitting it into the opcode and operand and using its instruction set.

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16
Q

What is the execute part of the FDE cycle?

A

Processor carries out the instruction.
If necessary data is fetch from/ stored to main memory
Result of any calculation is stored in the accumulator or registers.
Status register updated.

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17
Q

Go over hardware items.

A

Barcodes, camera etc,

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18
Q

How do hard disks work?

A

They are made up of multiple disks made of metallic material, arranged in a stack.
The disks are coated just a thin film of magnetic material.
Changes in the direction of magnitude represent 1’s and 0’s
The disks spin and heads read from of write to the disks.
The surface of the disk is organised into concentric tracks, which are split into sectors which can be individually addressed.

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19
Q

How do solid state drives work?

A

They use a type of programmable ROM chip, NAND memory.
NAND memory is made up of semi-conductors.
Data is organised into blocks, where a controller manages the blocks.
Semi-conductors retina their data without power because of a floating gate transistor, which is a floating gate coated in an oxide layer that traps charge, between a control gate and a silicon substrate.

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20
Q

What is the difference between static RAM and dynamic RAM?

A

Static RAM uses several transistors per bit of memory, where are dynamic RAM uses one.

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21
Q

On the system bus diagram what are the 5 sections?

A

Processor
Keyboard Input Controller
VDU Output Controller
Disk I/O
Memory

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22
Q

What is the cache?

A

Very small, fast memory within the CPU that stores regularly used data and instructions.

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23
Q

What are the advantages and disadvantages of synchronous data transmission?

A

Adv - allows communication in real time, reduced timing errors if properly synchronised, faster
Dis - expensive, and requires clocks to be synchronised.

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24
Q

What are the advantages and disadvantages of asynchronous data transmission?

A

Adv - easier to implement, flexible, cheaper
Dis - timing errors, increased overhead, slower

25
What is bandwidth?
The range of frequencies available on the carrier wave that carries the data. (Amount of data transmitted in a given amount of time along a communication channel.
26
What is baud rate?
The number of electronic state changes per second.
27
What are the three cause of latency?
Propagation - time taken for a logic gate to transmit data Transmission - time taken for data to pass through a cable Processing - time taken for data to travel around a network
28
What is PING?
When data is sent to another device it calculates how long it takes to come back.
29
What does a NIC do?
Enables a device to connect to a network.
30
What is a WAP?
A device that allows devices to wirelessly connect to a wired network.
31
What is Wi-Fi?
Method for connected devices wirelessly to a network.
32
What is SSID?
A 32-character unique code that identifies a wireless network.
33
What is a DNS?
A serve that contains domain names and their associated IP addresses.
34
How does a DNS system work?
It will translate a domain name into the IP address of the location of where that webpage is stored. Servers are organised into a hierarchy, where if one DNS server cannot resolve a lookup the query is passed to another.
35
What do ports do?
Identifies a particular process or application on a network.
36
What is SSH?
A protocol used for remote access to computers, by providing a secure encrypted channel of nodes.
37
What is port forwarding?
Routing data through ports to allow external users to access a device in a private network, by configuring the router to pass requests form its public IP address to an internal devices private IP address. Uses SSH
38
What is a socket?
An endpoint of a communication flow across a network.
39
What is DHCP?
A protocol for allocating locally unique IP addresses to devices when they connect to a network.
40
What is packet switching?
A method for transmitting packets of data via the quickest route on a network.
41
What is packet filtering?
Inspecting each packets header to ensure it doesn’t contain an malware and that it comes from a recognised source.
42
What is stateful inspection?
Examining the contents of each packet and checking that it comes from a know communication source and that it forms part of an existing series of packets.
43
What happens in the Application layer?
It provides protocols to allow communication between applications on different hosts. Sets an agreed upon standard between communication end points. Encrypts and decrypts data. Handles DNS
44
What happens in the Transport layer?
Uses the TCP protocol to establish and end-to-end connection with the recipient computer. Splits data into packets and reassembles them. Numbers packets Adds the port numbers of the sender and receiver.
45
What happens in the Network layer?
Defines the IP address of the sender and receiver. Handles the routing of packets and forwarding packets to end points Router uses routing table to instruct the next hop.
46
What happens in the Link layer?
Provides synchronisation of devices Adds the MAC address of sender and receiver Handles CSMA/CA and CTS/RTS protocols Manages Ethernet and Wi-Fi protocols
47
How does SMTP work?
Works through a series of SMTP servers which store the email addresses of senders and receivers. By linking with DNS servers the IP address of the recipient is identified and a connection is established between the sender and receiver.
48
How does POP3 work?
Creates a text file of any receive or incoming messages associated with an email address. Authenticates the client The client downloads all of the emails onto their device and the emails are deleted off the sever.
49
What is API?
A set of subroutines that provide an interface between one program and another.
50
What is the WebSocket protocol?
A set of rules that creates a constant connected between two computers on a network to enable real time collaboration and simultaneous data exchange (full-duplex connection) by sending a handshaking request through the HTTP port.
51
How do web applications work?
Client sends a request from the browser of the local machine. Domain name identifies the resource on the server. API is run from the server and accessed by the browser to co-ordinate processes between the client and sever applications. HTML files are used to ensure data is displayed in the correct format. All requests are transferred using HTTP to ensure data works on any local machine architecture. JSON / XML used to return the result.
52
What is first normal form in databases?
No repeating attributes All attributes are atomic.
53
What is second normal form in databases?
In first normal form No partial dependencies on the composite key
54
What is third normal form in databases?
In second normal form No non-key dependencies.
55
What is the functional programming paradigm?
When each line of code is made up of calls to a function, which in turn may be made of other functions or return a value.
56
What is the partial application of a function?
The process of partially applying a function to create an intermediate functions that performs part of the calculation.
57
What is a first-class object?
Any object that can be used an an argument or result of a function call.
58
What is a D-type flip-flop?
Stores one bit and flips it between 0 and 1. Input = single bit data and clock signal Output = single bit data, inverse of data output Output changes when the clock pulse is on a rising edge.