Term 2 Standard Examination 2018 ICT Services Management — COIT20246

a. Liz is trying to decide on which backup media she should use for her business. She is considering either magnetic hard disk or tape. Which medium would have the slower seek time? Which medium would be the more expensive? (2 marks) BASIS FOR COMPARISON MAGNETIC TAPE MAGNETIC DISK Basic Used for backup, and storage of less frequently used information. Used as a secondary storage. Physical Plastic thin, long, narrow strip coated with magnetic material. Several platters arranged above each other to form a cylinder, each platter has a read-write head. Use Idle for sequential access. Idle for random access. Access Slower in data accessing. Fast in data accessing. Update Can’t be updated Can Update Data loss If the tape is damaged, the data is lost. In a case of a head crash, the data is lost. Storage 20 GB to 200 GB Several hundred GB to TB Expense less more b. Describe what is meant by the term “stored program concept”. How did the approach change computing? (2 marks) ð The Stored Program Concept was suggested by Von Neumann. The idea was that the program is held in memory entirely so that the actual program can be modified by the computer while it is running. ð Various electronic and mechanical devices existed which could perform calculations of various types. They could be given inputs and produce the correct output. ð But if you wanted a device to do something different you had to physically modify the device. In this case as the instructions and data are held in the same memory you can treat them interchangeably. This makes it possible for the computer to do different things depending on the results of earlier calculations. ð The computer can modify its own software if the software is written to do so. c. Explain what is meant by the term “lossy” in the context of compression. Give an example of where it would be used and the name of such a type of compression. (2 marks) Downloaded by Samuel muthike () lOMoARcPSD| ð Lossy file compression results in lost data and quality