Storage.pptx

Storage Computer Fundamentals Storage It is a way to keep information long term. Old ways were to keep it stored on paper. Storage Device: A storage device is used in the computers to store data. It provides one of the core functions to modern computers. These devices can be classified based...

Storage Computer Fundamentals Storage It is a way to keep information long term. Old ways were to keep it stored on paper. Storage Device: A storage device is used in the computers to store data. It provides one of the core functions to modern computers. These devices can be classified based on accessibility by the computer and the methods through which they save their data.  Primary Storage Secondary Storage Tertiary Storage Offline storage Primary storage Also known as main memory. It is connected directly or indirectly to CPU through memory bus. RAM, ROM, Cache Secondary storage It is not directly accessible by CPU. Computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage. Hard disk Hard disk It is the main and usually largest data storage device in the computer. It can store anywhere from 160 GB to 2 TB. Hard disk speed is the speed at which data can be read or written to the disk. A hard disk unit comes with a set rotation speed varying from 4500 to 7200 rpm. Disk access time is measured in milliseconds. Tertiary storage Typically it involves a robotic mechanism which will mount and dismount removable mass storage media into a storage device. It is a comprehensive computer storage system that is usually very slow, so it is usually used to archive data that is not accessed frequently. This is primarily useful for extraordinary large data stores, accessed without human operators. Offline storage Also known as disconnected storage. Not under the control of a processing unit. Must be inserted or connected by a human operator. Floppy disk, USB flash drive, memory card How is Storage done? Paper Optical Magnetic Solid State Paper PROS CONS No need for electricity or Can be hard to make internet backups Confidential Information Hard to convert or reuse can be easily locked away Take up lots of space Optical Examples include CDs, DVDs, and Blu-Ray They use different reflections of light to read data, and use a laser to write data The information is held on the disc but you need a disc drive to access it. OPTICAL Pros Cons Reliable Per unit, have a smaller Good portability capacity than alternative Easy to pack and carry Slower read/write speed compared to alternatives Need a disc drive to use Magnetic Examples include hard disk drives (HDD), cassettes and swipe cards. Data is written by changing magnetism on the disk/tape and read by detecting this. Pros Cons Available with large Generally not durable capacities and cheap to (disks can break easily) buy Slower read/write times Usually reliable, although compared to SSDs failures do occur Solid State Drives Have no moving parts Electronic circuits are used to store the data Examples include SSDs and flash memory devices like USB memory sticks and memory cards (like SD cards) Pros Cons Generally reliable Higher cost per GB Can be very durable Sometimes have a limited Can be portable number of writes (leading to reliability problems long Generally faster term) read/write times