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Chapter 3 ict igcse

Chapter 3 ict igcse. Term Project Grade 9 Section B Due december 18 Find and research one Emerging technology not studied in class. It can be a prototype or already available in the market. Each student must present their findings Must use microsoft powerpoint

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Chapter 3 ict igcse

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  1. Chapter 3 ictigcse

  2. Term Project Grade 9 Section B • Due december 18 • Find and research one Emerging technology not studied in class. It can be a prototype or already available in the market. • Each student must present their findings • Must use microsoftpowerpoint • Presentation must have pictures and at least 5 slides, including a list of references • Student should be prepared to answer questions about their topic

  3. Main Memory - RAM The memory that a computer uses as a temporary work area is called Random Access Memory. The computer adds data and removes data from this memory. RAM is erased when the computer shuts off (volatile memory). When a computer is switch on, the operating system is copied into the RAM, any software that is run (such as Microsoft Excel) is also loaded into RAM and run from there. When a file is loaded (such as an excel file) that is also loaded into RAM. Main Memory - ROM Read Only Memory permanently stores data (non-volatile), can not be changed by the user. Usually only contains the instructions to initialize and start up your computer; program cycles in a washing machine/program instructions in games such as gameboys, playstations, etc. Backing Storage Place where data can be stored long term and be changeable. The only systems that do not need backing storage are those systems that are embedded in things, like washing machines. Backup Copy Making an extra copy of the data on your computer in case something happens to damage or delete your data.

  4. Comparing Main Memory with Backing Storage • It is always faster to access data from main memory than from backing storage. The processor can only use data and instructions that are in memory. • Data stored in main memory is lost when the computer is turned off but data stored in backing storage is not lost. • When programs are run or data files are loaded the contents are copied from the backing storage to the main memory of the computer • Main memory is much smaller than backing storage. It is far too small to hold the data and programs that would be on the backing storage.

  5. STORAGE DEVICES • Storage Medium = the part that holds the data • Storage Device = the machine that lets you store data on the medium and read data from it 3 Types of Storage Devices

  6. Fixed Hard Drives • Used as main storage because • They can store very large amounts of data • Access to the data is fast • There is no limit to the number of times they can delete data and then reuse the medium • Used to store 3 types of data • Operating system • Applications • User’s data, files, videos, etc. • These 3 types of data are all stored on the hard disk and then sent to the computers memory when they need to be used. • Stores and retrieves data much faster than a CD/DVD • Hard disks can crash. That is when read/write head crashes down on the surface of the hard disk (can cause data loss); fragile

  7. Portable Hard Disk • More robust than fixed hard disk; but can be damaged if dropped or mishandled • Used primarily to backup files and for transferring large files from one computer to another. • Data access times are fast; data transfer rate is fast; large capacity • Transfer rates are NOT as fast as fixed hard disks; more expensive than other forms of media

  8. Magnetic Tape • Magnetic tapes are very thin strips of plastic that are coated with a magnetic layer and are fed through a read/write head mechanism. • Used in any application that requires an extremely large storage capacity and where the speed of accessing data is not that important. • Batch processing • Utility billing systems – where all customer bills are produced at the same time and every customer record has to be processed • Making backups (usually larger organisations) • Cheaper than using disks; robust; data transfer rate is fast • Access to data is slow; updating requires a new tape to be created

  9. More than 60,000 slots for magnetic tape cassettesData Archiving

  10. OPTICAL STORAGE DEVICES • CD/DVD R • CD/DVD ROM • CD/DVD RW • DVD RAM • BLU RAY

  11. DO NOW IN COPYBOOK What is the difference between backing storage and main memory?

  12. Solid State Backing Storage • Memory Stick/Pen Drive/USB Drive • Storage medium and device are the same • Can store up to 64 GB of data • Used to transport files and backup data from computer to computer • Advantages • More compact than equivalent optical or magnetic media; very portable • More robust than other forms of memory, even surviving being “washed” • Disadvantages • More expensive per GB than hard disk drives

  13. Solid State Backing Storage • Flash Memory Cards • Can store up to 64 GB of data • Used for storing photographs in digital cameras • Used in mobile phones to store phone numbers, photographs, etc. • Used in MP3 players to store music • Advantages • More compact than equivalent optical or magnetic media Disadvantages • More expensive per GB than hard disk drives; can only be used • for a particular number of read/write operations • Have lower storage capacity than hard disk drives

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