2 Flashcards

1
Q

What is the difference between secondary and primary memory ?

A

Primary: CPU has direct access to (registers, cache, ROM & RAM)
Volatile ( only on with power)
Fast read/write speed
Secondary: not directly accessible
Non-volatile
Where data is stored when not in use
Slow read/ write speed

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2
Q

Magnetic Hard Disks

A

Made up of magnetised metal disks spinning .
1 &0 for magnetised and demagnetised
Data is stored in sectors , on tracks.
Read write head on a movable arm accesses these sectors.
Long lasting( but moving parts), cheap, large capacity

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3
Q

Solid state (flash)

A
Drive:
Data stored in electrical circuits, by tapping electrons. (Transistors)
Fast read write time. 
Don’t need defragmentation 
More long lasting, no heat
no moving parts, 
Silent
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4
Q

Optical discs

A

Eg: CD, DVD, blue Ray
Pits/ (0)holes are made, the reflected beam from laser read is the data
Low capacity, cheap, portable , slow read/write

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5
Q

What is Cloud storage

A

Data is uploaded via the internet to a remote server (stored on HDD/SSD) . You pay with a subscription.

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6
Q

Roles of the OS

A

Communicating with input output devices/ via device driver
Process manager- CPU and it’s time with programs
Providing a platform for applications to run
Memory management- how much RAM a program has access to
File management-read/write/delete
System management- user passwords

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7
Q

Why is secondary storage required?

A

To store long term
Retains data when no power (non-volatile)
High capacity

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8
Q

What is durability?

A

How much physical damage it can take without breaking

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9
Q

Put in order , in terms of how quickly data is transferred (speed)

A

Solid
Magnetic
Optical

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10
Q

What are the shapes for AND, OR,NOT and XOR

A

And- D
Not-triangle &circle
Or- arrow head
XOR- arrowhead with line, does not accept two trues

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11
Q

How do you calculate the total number of combinations for a truth table?

A

2 * * number of inputs
Eg:
2* * 3 =8
2**2= 4

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12
Q

Symbols for NOT, OR, AND, NOT OR

A

Not= line overhead
And = .
Or= +
Not or = circle over +

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13
Q

What are advantages and disadvantages of cloud storage?

A

:)can be accessed from anywhere,
data can be shared ,
cheap,
provides back up/security

:( need Wi-Fi,
data vulnerable to hackers,

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