1.2 Types of information storage media You should know about different types of information storage media and devices and their characteristics. This should lead to an understanding of the use and advantages/disadvantages of both media and devices in a given context. • paper (e.g. forms, handwritten notes, maps, telephone directories) • optical media (e.g. CD and DVD) • magnetic media (e.g. magnetic hard drives and tapes) • solid state media (e.g. SSD hard drives, memory cards) • characteristics • purpose • advantages and disadvantages Information can be held in many different ways: THINGS TO THINK ABOUT Paper is still a form of information storage! Being without a USB memory stick now is rare Capacity is growing whilst size is shrinking 5 years ago 256 MB was regarded as high capacity! SD cards are similar to USB sticks but smaller Why would governments ban SD cards from a lot of government buildings? Paper This is a traditional form of information storage and includes forms, handwritten notes, maps and telephone directories. However it is easily damaged when handled, costs a lot to transport and can be hard to keep secure.   Optical Media Better known as music and film storage formats. CDs and DVDs are methods of digital information and data storage that can hold information of many types. One of the key uses is for software distribution. They are called optical media because they are written and read by laser. Magnetic Media Magnetic media uses magnetic patterns to store data. The most common example is the magnetic hard drives inside most computers. Data can be stored on external hard drives. Data can also be stored on tapes (this media is most frequently used for backup or archiving).

Solid State Media Are rapidly taking over from HDDs. They store data and information in circuitry rather than a magnetized disc or tape. An example is a SSD card. They have no moving parts and all data is retrieved at the same rate no matter where it is stored (so are faster than HDDs). They have the additional advantage of not requiring air cooling as their lack of moving parts mean they don’t overheat. The most common type of solid state storage devices store data by controlling the movement of electronics within NAND* chips. However, a number of solid state storage devices sometimes use electronically erasable programmable read-only memories (EEPROM) technology. The main difference is that it uses NOR* chips rather than NAND. This makes them faster in operation; however, devices using EEPROM are considerably more expensive than those that use NAND technology. EEPROM also allows data to be erased in single bytes at a time. Use of NAND only allows blocks of data to be read or erased. This makes EEPROM technology more useful in certain applications where data needs to be accessed or erased in byte-sized chunks. Characteristics Different forms of storage media have different characteristics, for example: Mutability The ability to change the content of a storage medium. Some devices, especially CDs and DVDs, are in a read-only format and cannot be edited. Other devices (and media like paper) are in read/write format which allows repeated reuse. Robustness Solid state media, because it has no moving parts, is less likely to be damaged if dropped and so is often used in portable devices while hard drives, which rely on an internal spinning disc as the storage medium, are frequently damaged if dropped. If magnetic media is placed near magnets the information held on them can become inaccessible. Access to Data For example tape storage has to be searched from beginning to end to find a particular file and is best used for storage that does not require quick access to particular files. Cost Paper is relatively cheap but the cost of sending large amounts of paper-based information (such as books) by post or courier are high because of their weight. Hard drives remain cheaper but slower than SSD cards, although hybrid storage options are available. Storage Capacity The amount of data that can be stored on each device. As miniaturisation has progressed so more data can be held on most forms of storage. Energy Consumption Data density Weight Environmental considerations  

Purpose To store information. Once you have decided to store information you have to decide how easily you need to access the information for the given purpose. For example the relative difficulty accessing information held on a data tape means that it is an unsuitable format for general day-to-day storage.   Advantages and disadvantages Different storage media can have different advantages and disadvantages which will influence the choice of media for a given purpose. For example the robustness of solid state devices means that they are extremely useful in devices that are likely to be dropped. As desktop and laptop devices are less likely to be dropped magnetic hard discs are more likely to be used, and the advantage of the relative cheapness of these storage devices is reflected in the price of the device. Another example (that is now being superseded by another storage device) is making a copy of a music CD to keep in the car. This copy may not be looked after as well as the original music CD but if damaged the low cost reduces the financial implications and a second copy can easily be made. ADDITIONAL – Cloud Storage This is becoming more common, specifically within work and those who work from home. Cloud storage is a form of data storage in which the digital data is stored in logical pools, the physical storage spans multiple servers, and the physical environment is typically owned and managed by a hosting company. These cloud storage providers are responsible for keeping the data available and accessible, and the physical environment protected and running. People and organisations buy or lease storage capacity from the providers to store user, organization, or application data.

Knowledge Check 1 – Individual Task 3 QUESTIONS What storage would you upgrade on your computer at home to make it better? Why? Why do we still have unreliable Hard Drives in computers? What is the difference between SSD and HDD? What is the main disadvantage of SSD? Why do companies use magnetic tape to create backups? Think of one example where paper would be the best information storage medium – why?   Extension Research the different types of storage media, including examples of the key characteristics (e.g. cost, energy consumption, robustness, data density, weight, environmental considerations etc.), advantages and disadvantages of each and some possible uses for each example. Exam Question