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A Level Computer Science > 113-input-and-output-and-storage > Flashcards

113-input-and-output-and-storage Flashcards

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1
Q

Input devices

A
  • Peripherals that receives data from user/outside world
  • Input can be manual e.g mouse or automated e.g sensor
  • specialised devices: sip/puff switches, foot switches, Braille keyboards for disabilities
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2
Q

Factors to consider when choosing a device

A
  • accessibility
  • accuracy
  • speed
  • compatibility
  • cost
  • purpose
  • user preferences,
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3
Q

Method for data inputs (Manual or automated)

A
  • manual: flexible and adaptable, informed decisions, small data requiring human interpretation
  • automated: less error-prone and expensive, done by device, faster and efficient esp for large amounts
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4
Q

Output devices

A
  • Peripherals that provides data to user/other devices
  • convert digital data from a computer system into a format that humans can process (sound, images, vibrations)
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5
Q

Storage Devices:

A
  • medium that holds data and programs temp/perm
  • internal examples: RAM, solid-state hard drive, magnetic hard drive.
  • external examples: optical disk, USB drive, memory card, external hard drive.
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6
Q

Choosing Secondary Storage Properties to Consider:

A
  • Capacity and cost
  • Read and write speed
  • Portability: its size and weight and ability to be easily transported.
  • Durability: withstand wear and tear overtime
  • Robustness: withstand physical stress like impact or vibrations
  • Compatibility: Is the device’s interface and own connectors compatible with the user’s system and connectors
  • Reliability: to store data without corruption or loss.
  • Longevity: how long the storage mechanism can be expected to function properly before failing
  • Integrity: how trustworthy the data on a device is. if low integrity, it’s not reliable or accurate, can happen due to corruption, tampering, or errors.
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7
Q

Storing data considerations

A
  • Backing up important data
  • Redundancy: creating duplicate copies of data on multiple disks or servers to protect against data loss in case of hardware failure.
  • Encryption: protect against unauthorized access to sensitive data.
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8
Q

Drive and Media

A
  • drive: hardware device used to access/write data on a storage medium.
  • media: physical object/material where the data is actually stored
  • e.g hard disk drive (HDD) is a hardware device (drive) that reads and writes data to a magnetic storage medium (disk inside the hard drive where data is stored)
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9
Q

Magnetic storage

A
  • uses two magnetic state: magnetised (1) and demagnetised (0)
  • data is stored on a platter (magnetic disk)
  • read/write heads used while platter spins
  • hard disk drives, portable HDDs, floppy disk drives, and tape drives
    -backups, archives
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10
Q

pros of Properties of Magnetic Storage

A
  • High capacity 1-12TB: large quantity of data stored compactly
  • cost-effective, very low cost per gb
  • good reliability, lasts a long time
  • not portable: moving parts but can be portable (portable hard disk drives/magnetic tapes) which are easily connected to devices
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11
Q

cons of magnetic storage properties

A
  • slow: moving parts (read/written sequentially, head moves through all preceding data)
  • magnetic: particles on platter can demagnetise over time, causing data loss/corruption, or could get corrupted near a magnetic field.
  • Moving parts so not durable(susceptible to wear n tear) and not robust (delicate and prone to damage from movement) can cause mechanical failure,data loss, or break during impacts/vibrations
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12
Q

Optical Storag

A
  • optical drive (uses a laser beam)
  • optical media (store data using microscopic pits (0) and lands(1) e.g Blu-ray
  • used for music, films, software, games and backing up data.
  • laser burns indentation marks in spiral tracks into reflective disc surface.
  • Laser light shone detects where marks are and translates it into readable format: if hits a land, reflected into a sensor, reflected elsewhere if hits pit
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13
Q

pros of optical storage properties

A
  • robust: waterproof and shockproof
  • low cost per GB
  • portable and has no moving parts
  • be backed up easily.
  • compatible with a wide range of devices, including computers.
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14
Q

cons of optical storage properties

A
  • parts in the drive have to move to find the right bit of data on the disk, slow access times and writing speed - but quicker to read than write.
  • easily scratched and has low durability.
  • small capacity (700 MB to 50 GB), each disk has a small capacity but multiple disks can be used to gain higher capacity of storage.
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15
Q

Types of Optical Storage

A
  • CDs - 720mb. Audio files, text, digital images.
  • DVDs - stores games or standard definition movies for home viewing. 4.7-8.4 single disk gb. Digital videos.
  • Blu-ray disks - high definition movies/games. 25-50 gb.
  • Re-writable (RW) e.g CD-RW: can be written and read as many times, used for backups updated regularly
  • Write-once (R) - written once by user, then cannot be overwritten, can be read many times. Used for copying data.
  • ROM - data pre-written by manufacturer, cannot be overwritten. used for music, films, software, games.
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16
Q

Flash Memory

A
  • electrically erasable programmable read-only memory (EEPROM) used to create many flash memory devices:
  • USB drives, SSDs, SD cards, ROM chips are made from EEPROM.
  • Used in digital cameras, smartphones, and solid-state drives
  • Flash memory is the underlying technology used in solid-state storage devices
17
Q

solid state storage

A
  • Made of microchips with switches where 1 or 0 is stored, using silicon semiconductors forming logic gates NAND/NOR to store electrical charge
  • Uses flash memory to store data so can be erased and reprogrammed electronically
  • USB flash drives, solid state drives, memory cards, sd VARDS
18
Q

pros of Solid state storage properties

A
  • Faster access times - no moving parts = durable + no waiting for parts to move when accessing data
  • Robust - not easily damaged by shocks, suitable in industrial machinery and vehicles (exposed to lots of vibrations)
  • large capacity (250GB-2TB),
  • Highly portable and lightweight, used in smaller devices e.g smartphones and tablets.
19
Q

cons of solid state storage properties

A
  • easily damaged by exposure to high temperatures/other environmental factors
  • expensive
  • Limited read-write cycles and lifetime - each time the memory is flashed, it wears down, lose access to drive once flash memory degraded past a point and becomes unreliable, leading to potential data loss + unusable
  • Re-writable devices often include several blocks of flash memory, only one block must be flashed at a time and so the device will last longer.
20
Q

Types of solid state/flash memory storage

A

Secure Digital (SD) cards - SD cards are used to extend the capacity of devices such as: Cameras, Smartphones, Tablets - high capacity for their physical size. This is useful in these smaller devices.
Solid State Drives (SSD) - SSDs are often used in home computers because of their performance - form of re-writable flash storage.

21
Q

Primary Storage

A
  • Memory that can be accessed directly by the processor
  • Each memory location has a physical address used to locate and access its contents
  • Used by the computer’s operating system to run the computer
  • Stores code instructions to execute and files required by running programs
22
Q

RAM

A
  • Volatile memory that holds programs currently in use, open applications, data in use, and the operating system
  • Easily removed from the computer and upgraded/expandable/replaced
  • Needs constant refreshing to stay active
  • Contents change frequently
  • Faster than secondary storage like hard disk drives (HDDs)
  • ram is much more expensive per unit capacity than secondary storage media
23
Q

ROM

A
  • stores boot up sequence for the bios which boots up computer, check the computer system for errors and loads operating system.
  • Very small capacity
  • hold the device drivers for interfacing with the input and output devices
  • Embedded in the motherboard and usually not removed
  • non-volatile and no need to refresh data as it is permanent
  • Only interacts with the CPU under certain conditions
  • Useful for storing fixed sequences of instructions, e.g. computer’s startup bootstrap routine
  • Cannot be modified, useful for storing content distributions and storing instructions for embedded systems
24
Q

secondary storage

A
  • Long-term, non-volatile storage used to permanently save files, data, and programs when computer is switched off and is not constantly connected to the computer.
  • Provides larger storage capacity
  • ROM cannot be written to, RAM is volatile and loses data when the computer is turned off. Necessary to back up data stored to prevent data loss.
  • Not directly accessible by the CPU, unlike RAM and ROM.
  • Includes SSDs and HDDs
  • Some computer systems do not use secondary storage.
25
Q

virtual storage (basically cloud storage although cloud storage typically refers to a specific type of virtual storage service provided by a third-party provider)

A
  • abstraction from the user of multiple drives formatted to act as one single logical storage (data spread across multiple physical storage devices: harddrives, solid state drives, servers in cloud)
  • files can be stored/retrieved in the same way as a physical drive but as remotely over the internet, can be accessed by any computer on the same system (cloud storage service/ networked storage e.g)
    -OS/virtual storage software decides where to store the data based on factors(free space, access speed, redundancy requirements)
  • Useful for organising network resources and cloud computing, files spread across a range of servers.
    -same pros and cons as cloud storage
26
Q

Logical storage

A
  • Logical storage is the perceived storage area, while physical storage is the actual implementation and virtual storage is abstraction of logical storage from physical storage
  • Example: a shared drive on a school network appears as a single storage area to students, but the folders and files may be stored across different media
27
Q

Cloud Storage

A
  • provides remote storage space for data accessible over the internet from anywhere.
  • Data is stored on the internet and remotely in large centre data servers across the world and managed by cloud providers
  • used for backup, disaster recovery, sharing files, and collaboration.
28
Q

Cloud Storage Pros

A
  • Cost-effective: eliminates need for on-premises/own storage infrastructure and maintenance costs.
  • Scalability: storage capacity easily scaled up or down as needed, perception of unlimited storage.
  • Easy Accessibility: data can be accessed from anywhere with an internet connection and allows for file sharing and collaboration.
  • Automatic backups: most providers automatically back up data.
  • Addition: Can be configured for hybrid setups, allowing for a mix of cloud and on-premises storage.
  • Environmentally friendly: reduces e-waste and carbon emissions
29
Q

Cloud Storage Cons

A
  • Security: vulnerable to cyber-attacks and breaches.
  • Reliability: reliant on internet connectivity, no access to files without internet connection, and third-party service providers.
  • Privacy: raises concerns around data ownership and privacy.
  • Speed: slow uploads and downloads, subject to bandwidth limitations. so may be slow access times with poor connectivity
  • Compliance with data protection regulations (e.g. GDPR) is important when using cloud storage, as data may be stored in different countries with different laws.
  • Cost: need to pay to upgrade storage capacity and sometimes its monthly
30
Q

Cloud Computing vs Cloud Storage

A
  • Cloud computing encompasses a broad range of services, including cloud storage, servers, databases and software over the internet on demand without physical infrastructure
    Cloud storage is a specific type of cloud computing service focused solely on remote data storage.
31
Q

Virtual Network

A
  • software emulation of a network that allows you to connect devices and systems together even if they are geographically different
  • provides an isolated and secure connection between them (traffic is kept separate)
  • used cloud computing environments to connect servers and data centres together
    -example is a VPN
32
Q

Virtual Server

A
  • software to emulate multiple instances of a server
  • allows multiple virtual servers to run on a single physical server, with each virtual server having its own operating system, applications, and resources.

A Level Computer Science (25 decks)

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