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Data Storage - Coggle Diagram
Data Storage
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Internal:
- Hard Disk Drive (HDD)
- Solid State Drive (SSD)
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Devices such as CD’s, DVD’s, and Blu-Ray discs.
They use different reflections of light to read data, and use a laser to write data.
Data is stored on the disc but a disc drive is needed to read the data.
Advantages:
- Reliable
- Fairly durable (but vulnerable to dust and scratches)
- Good portability, they are easy to pack and transport.
Disadvantages:
- Per unit, have a smaller capacity than alternatives
- When buying in bulk the price may be quite attractive but data is likely to be split across disks (inconvenient)
Magnetic Storage
Hard Disk Drives (HDDs), Cassettes, and some swipe cards (debit/credit cards with magnetic strip).
Data is written by changing magnetism on the disk, and read by detecting it.
A HDD works using disks which spin thousands of times per minute.
Advantages:
- Large Capacity for a cheap price
- Usually reliable although failures do occur
Disadvantages:
- Generally not portable
- Generally not durable, disks can break easily
- There are faster alternatives
Solid State Storage
Solid State Storage could be both internal and external. Flash memory cards, USB sticks and solid state drives.
Unlike optical and magnetic storage, these have no moving parts and only use circuits to store data.
Advantages:
- Generally reliable
- Can be very durable
- Can be very portable
- Very fast read / write times compared to alternatives.
Disadvantages:
- For the same cost, their storage capacity is much lower than magnetic
- Finite writes (long term reliability problems). This is less of a problem with more modern Solid State Storage
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Cloud storage is when data is stored on multiple
computers in a separate location.
These servers primarily use magnetic storage but some, more modern servers may also use solid state storage.
Data is usually accessed through some sort of web interface or online file explorer. Most cloud storage companies also have desktop applications that “synchronise” files to and from the cloud to your devices.
To be competitive, large data centres are needed. This is why cloud storage providers are typically owned by large technology companies.
Advantages:
- Large providers are reliable and stable
- Files can be accessed from anywhere (convenient)
- Backup copies of data and version control may be available
Disadvantages:
- Internet connection is needed
- For small users the cost may be high and is not usually a one-off payment. For example most cloud storage providers offer monthly subscriptions
- No control over security or the location of the servers
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Modern businesses collect huge amounts of data. An organised collection of related data is called a data set.
Big Data is a data set that is so big that traditional data processing software can no longer handle it. By big we mean Petabytes (1,000 TB) of data, and maybe even Exabytes (1,000 PB).
The data may also be a mix of different data types or even contain data that is not associated with a specific type (making it complex).
Advantages:
- Analysis can reveal trends and patterns. This is called data mining
- Similar data sets can interact to share data
- As they are organised, searches can be performed to find specific data
Disadvantages:
- As data sets grow, processing time increases
- Interactions between data sets can lead to data duplication. This would then require data cleaning
- Poor data collection will lead to poor analysis - Garbage In, Garbage Out (GIGO)
- Poor data collection will lead to poor analysis - Garbage In, Garbage Out (GIGO)