data storage devices

data storage devices

1. types of data storage devices

   • Ram (random access memory)
     • the ram is a temporary storage device used to store information
     • once the computer is shut down everything on the ram is lost
     • the ram is attached to the motherboard
   • hard drive
     • the hard drive is where the information is stored on a computer permenantily
     • unlike the RAM the information will always be stored on the hard drive
     • A portable hard-drive is one that is placed into a small case along with some electronics that allow the hard-drive to be accessed using a USB or similar connection
     • hard drives have developed massively over the past years
     • Fixed Hard Drive A hard-drive built into the case of a computer is known as ‘fixed’. Almost every computer has a fixed hard-drive.
     • Portable hard-drives allow very large amounts of data to be transported from computer to computer.
   • magnetic storage devices
     • Magnetic storage media and devices store data in the form of tiny magnetised dots. These dots are created, read and erased using magnetic fields created by very tiny electromagnets
     • In the case of magnetic tape the dots are arranged along the length of a long plastic strip which has been coated with a magnetisable layer (audio and video tapes use a similar technology).
   • blue ray
     • Blu-Ray disks are a recent replacement for DVDs. A Blu-Ray disc can hold 25 - 50GB of data (a dual-layer Blu-Ray disc can hold twice that). Blu-Ray discs are random-access devices.
     • Blu-Ray discs are used in the same way as DVD-ROMs (see above) but, since they can hold more data, they are also used to store very high-quality, high-definition (HD) video.
   • USB memory
     • Memory sticks (or ‘thumb-drives’) have made many other forms of portable storage almost obsolete (why burn a CD or DVD when you can more easily copy your files onto a memory stick?).
     • Memory sticks are non-volatile, random-access storage devices.
     • Each of these small devices has some flash memory connected to a USB interface. Plug it into your computer and it appears as a drive. You can then add files, erase files, etc. You can use it to move any type of file between computers.
   • memory card
     • Many of our digital devices (cameras, mobile phones, MP3 players, etc.) require compact, non-volatile data storage.
     • Flash memory cards provide this and come in a variety of shapes and sizes.
     • by digital cameras is the SD Card. The cards store the digital images taken by the camera.
   • smart card
     • Many credit cards (e.g. ‘chip-and-pin’ cards), door entry cards, satellite TV cards, etc. have replaced the very limited storage of the magnetic strip (the dark strip on the back of older cards) with flash memory
     • . This is more reliable and has a much larger storage capacity. Cards with flash memory are called smart cards.