3 - STORAGE: TYPES AND CHARACTERTISTICS

Digital Device Storage… What do you store on: Your phones? On your computers? Tablets? Why do we need storage devices? What could computers do without storage devices?

Big Picture - Storage In this topic, you need to understand: the need for secondary storage data capacity and calculation of data capacity requirements common types of storage: optical, magnetic. solid state suitable storage devices and storage media for a given application, and the advantages and disadvantages of these, using characteristics: capacity, speed, portability, durability, reliability, cost

Learning Objectives By the end of today’s lesson, you will be able to: Identify the need for and purpose of secondary storage Describe common types of storage Match storage devices to their type of storage Explain the characteristics of common types of storage

Brainstorm In pairs, list all the different storage devices that you can think of….. (don’t rub them off yet!)

What is Secondary Storage? Long term storage of data, files, software, OS. Why do we need to store these things? To access it again later To use software To interact with the computer What would happen without secondary storage? Software would need to be installed each time we use it You couldn’t save any files, data, images, videos etc permanently. X X

Secondary storage compared to memory It is always slower to access data from secondary storage Data stored in secondary storage is permanent so it is NOT lost when the power is turned off Whereas…. Data stored in internal memory such as RAM is lost when you turn the device off When you run a program, or load a file, the data is copied from secondary storage into internal memory. When you save a file, it is copied from internal memory into secondary storage

Types of Storage Optical Magnetic Solid State/Flash

Optical A laser light creates marks in a pattern on the disk A laser light detects where the marks are and translates this into a readable format

Magnetic Read/write head moves across the medium and changes how magnetised that part of the medium is E.g. one level of magnetism will be a 1, a second will be a 0

Solid State This is made of microchips (switches) The state of the switches determine if a 1, or 0 is stored

Look back at your starter board Identifying if each storage device that you wrote down is magnetic, optical or solid state. Optical Magnetic Solid State/Flash

Possible Answers Device Magnetic Optical Solid state Hard Disk Drive    Solid State Drive Blu ray DVD ROM SD Card USB Memory Stick CD ROM Tape Drives

Characteristics of Storage Devices Capacity how much data can it store? Speed how fast can it access the data? Portability how easy is it to move it from one place to another Durability how well does it last e.g. if it is dropped Reliability how consistently does it perform Cost how much does it cost per KB, MB or GB?

Characteristics of Storage Devices Type of device Capacity Speed Portability Durability Reliability Cost Optical Magnetic Solid State Based on your research and knowledge, rank each type of storage device: 1 is best > 3 is least good Disclaimer: these rankings are ‘in general’, there are likely to be many individual devices that do not quite fit this pattern.

Characteristics of Storage Devices Type of device Capacity Speed Portability Durability Reliability Cost Optical 3 2 Magnetic 1 Solid State 1 is best > 3 is least good Disclaimer: these rankings are ‘in general’, there are likely to be many individual devices that do not quite fit this pattern.

Now you need to: Log into Moodle Go to ICT & Computing GCSE Computer Science 2016-18 Computer Systems 1.3 - Storage iBytes 3.1 Types of Storage Download, save and then complete the work sheet Storage_L1 Next, complete the Storage Mind Map

Types of storage mind map Complete the mind map with: The three types of storage A definition of each type of storage A list of example devices The characteristics for that type of device

Plenary: Look back at your table for Q5 Which of these devices can store the most data? Which of these devices can store the least data? Which of these devices is the cheapest per MB? Which of these devices is the most expensive per MB? Which of these devices is easiest to put in your bag and take with you? Which of these devices is most likely to get damaged?