Storing Data

1. Storing Data

2. Thislesson will cover: • The difference between bits and bytes. • The difference between ROM,RAM,and cache. • The advantages and disadvantages of different types of storage device.

3. Data storage Being able to store data is fundamental to processing and changing data into relevant information. What data storage devices do you use at school/home?

4. Units of memory A computer only understands the numbers 0 or 1, or whether a switch is on or off. We call those 1s and 0s ‘bits’ – binary digits. Abyte (made up of 8 bits) is enough computer memory to store a single character of data (e.g. the letter ‘F’ in ACSII). 1KB is actually 1,024 bytes (210), not 1,000 as you might expect, but most people think in multiples of 1,000. 1megabyte(MB) is 1,000KB(220) 1gigabyte(GB) is 1,000MB (230) 1terabyte(TB) is 1,000GB(240).

5. Match the pairs

6. Types of memory

7. RAM and ROM

8. Types of backup storage

9. Backing storage – hard drives • The hard disk of the computer stores the system information, programs and data thatthe computer uses every day. • Network storage is very common for most large organizations. They use RAID systems/servers which connect multiple hard drives to create huge storage space. The drives are mirrored: any data added is copied to multiple drives, so if one drive fails, the others will still hold the data. • Removable hard drives plug into the USB port and can be used for backup or transfer of data to another computer.

10. Backing storage – optical There are two main types of optical storage: CD and DVD.They look exactly the same, but DVDs hold much more data than CDs and need different drives to read them. • CD-ROMsare read only – you can read data from them but can’t write more data to them. • CD-Rs allow you to write data once, but you can’t write over it. • CD-RWs allow you to write data and then record new data over it. • DVD-Rs and RWs follow the same pattern. • Blu-Ray discs require a different type of laser to read and write data. Very few computers currently have Blu-Ray readers/writers.

11. Backing storage – flash memory In recent years, flash memory has become much more popular. • It holds a lot of data in a very small space. • It can save/retrieve data very quickly. • Most computers will recognize the device as soon as you plug it in. • Flash memory sticks connect through USB or FireWire ports. • Many other devices, like digital cameras and MP3 players, also use flash memory. • Flash memory cards can hold different types of data so your MP3 player could hold a data file with your homework on it, for example.

12. Storage capacity

13. Case study: death of the floppy disk Advances in storage technology mean that old forms of data storage can become obsolete. During the 1980s and early 1990s magnetic floppy disks were very common. They held about 1.44MB which was enough for most user needs in these eras. However, as graphics, music and video files became common to share, the disks no longer met the demands of consumers. Sony announced that they would stop manufacturing floppy disks in 2011 despite some customers still using them. Do you think the same thing will happen to CDs? A new technology, Holographic Versatile Discs, could hold up to 10TB on a disc the same size of a CD.

14. Cloud storage A lot of data is now stored inthe cloud. Cloud storage refers to virtual storage, where the data is stored on large servers hosted by companies like Google, Apple and Microsoft. Users can simply log onto their account and access their personal data from anywhere with an Internet connection. Cloud computing reduces the need for users to carry storage peripherals as their data is always available on demand. Google docs is an example of cloud storage.

15. Summary