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Genetic Computer School Computer Systems Fundamentals

Genetic Computer School Computer Systems Fundamentals. Lecturer: Dr. Nguyen Nam Hong Tel: (04) 8 781 437 Mobile: 0912 312 816 Email: nguyennamhong2003@yahoo.com.au Chapter 4. Storage Devices. Chapter 4. Storage Devices. Storage trend (revision). Chapter 4. Storage Devices.

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Genetic Computer School Computer Systems Fundamentals

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  1. Genetic Computer SchoolComputer Systems Fundamentals Lecturer: Dr. Nguyen Nam Hong Tel: (04) 8 781 437 Mobile: 0912 312 816 Email: nguyennamhong2003@yahoo.com.au Chapter 4. Storage Devices Dr. Nguyen Nam Hong, Le Quy Don University

  2. Chapter 4. Storage Devices Dr. Nguyen Nam Hong, Le Quy Don University

  3. Storage trend (revision) Dr. Nguyen Nam Hong, Le Quy Don University

  4. Chapter 4. Storage Devices 4.1. Main Memory. 4.2. Types of Main Memory. 4.3. Difference Between Primary and Secondary Storage. 4.4. Permanent Storage Devices. Dr. Nguyen Nam Hong, Le Quy Don University

  5. 4.1. Main Memory (1) • Used for temporary program and data storage read from disk drives. • Programs passed to CPU for execution • Data passed to CPU for modification and returned to memory • Data is written from memory to disk when saving Dr. Nguyen Nam Hong, Le Quy Don University

  6. 4.1. Main Memory (2) • More RAM, more data can be retained in memory rather than written to hard disk drive. • Improves system performance by reducing hard disk drive access. Dr. Nguyen Nam Hong, Le Quy Don University

  7. 4.2. Types of Main Memory 4.2.1. ROM (Read Only Memory). 4.2.2. RAM (Random Acess Memory). Dr. Nguyen Nam Hong, Le Quy Don University

  8. 4.2.1. ROM (Read Only Memory) 4.2.1.1. ROM. 4.2.1.2. PROM. 4.2.1.3. EPROM. 4.2.1.4. EEPROM. Dr. Nguyen Nam Hong, Le Quy Don University

  9. 4.2.1.1. ROM • Acronym for Read-Only Memory. • Any semiconductor circuit serving as a memory that contains instructions or data that can be read but not modified (whether placed there by manufacturing or by a programming process, as in PROM and EPROM). Dr. Nguyen Nam Hong, Le Quy Don University

  10. 4.2.1.2. PROM • Acronym for Programmable Read-Only Memory. • A type of read-only memory (ROM) that allows data to be written into the device with hardware called a PROM programmer. • After a PROM has been programmed, it is dedicated to that data, and it cannot be reprogrammed. Dr. Nguyen Nam Hong, Le Quy Don University

  11. 4.2.1.3. EPROM • Acronym for Erasable Programmable Read-Only Memory. • A nonvolatile memory chip that is programmed after it is manufactured. • EPROMs can be reprogrammed by removing the protective cover from the top of the chip and exposing the chip to ultraviolet light. • Though EPROMS are more expensive than PROM chips, they can be more cost-effective if many changes are required. • Also called reprogrammable read-only memory (RPROM). Dr. Nguyen Nam Hong, Le Quy Don University

  12. 4.2.1.4. EEPROM • Acronym for Electrically Erasable Programmable Read-Only Memory. • A type of EPROM that can be erased with an electrical signal. • It is useful for stable storage for long periods without electricity while still allowing reprogramming. • EEPROMs contain less memory than RAM, take longer to reprogram, and can be reprogrammed only a limited number of times before wearing out. Dr. Nguyen Nam Hong, Le Quy Don University

  13. 4.2.2. Random Acess Memory 4.2.2.1. RAM. 4.2.2.2. SRAM. 4.2.2.3. DRAM. 4.2.2.4. SDRAM. 4.2.2.5. NVRAM. Dr. Nguyen Nam Hong, Le Quy Don University

  14. 4.2.2.1. RAM • Acronym for Random Access Memory. • Semiconductor-based memory that can be read and written by the central processing unit (CPU) or other hardware devices. • The storage locations can be accessed in any order. • Note that the various types of ROM memory are capable of random access but cannot be written to. • The term RAM, however, is generally understood to refer to volatile memory that can be written to as well as read. Dr. Nguyen Nam Hong, Le Quy Don University

  15. 4.2.2.2. SRAM • Acronym for Static Random Access Memory. • A form of semiconductor memory (RAM) based on the logic circuit known as a flip-flop, which retains information as long as there is enough power to run the device. • Static RAMs are usually reserved for use in caches. Dr. Nguyen Nam Hong, Le Quy Don University

  16. 4.2.2.3. DRAM • A form of semiconductor random access memory (RAM). • Dynamic RAMs store information in integrated circuits containing capacitors. • Because capacitors lose their charge over time, dynamic RAM boards must include logic to refresh (recharge) the RAM chips continuously. • While a dynamic RAM is being refreshed, it cannot be read by the processor; if the processor must read the RAM while it is being refreshed, one or more wait states occur. • Despite being slower, dynamic RAMs are more commonly used than RAMs because their circuitry is simpler and because they can hold up to four times as much data. Dr. Nguyen Nam Hong, Le Quy Don University

  17. 4.2.2.4. SDRAM • Acronym for Synchronous DRAM. • A form of dynamic random access memory (DRAM) that can run at higher clock speeds than conventional DRAM by employing a bursting technique in which the DRAM predicts the address of the next memory location to be accessed. Dr. Nguyen Nam Hong, Le Quy Don University

  18. 4.2.2.5. NVRAM • NVRAM: non-volatile RAM. • Flash memory (USB disk): 32 MB to 10 GB. • Addvantage: • They are much faster to access than disk storage. • They comsume less power than disk storage. • Disaddvantage: • They cannot be written to as quickly as ordinary RAM. • They are more expensive than disk storage. Dr. Nguyen Nam Hong, Le Quy Don University

  19. NVRAM Examples Dr. Nguyen Nam Hong, Le Quy Don University

  20. 4.3. Difference Between Primary and Secondary Storage Dr. Nguyen Nam Hong, Le Quy Don University

  21. 4.4. Permanent Storage Devices 4.4.1. Magnetic disk storage. 4.4.2. Optical disk storage. 4.4.3. Magnetic Tape storage. Dr. Nguyen Nam Hong, Le Quy Don University

  22. 4.4.1. Magnetic disk storage 4.4.1.0. Magnetic disk overview 4.4.1.1. Floppy disk. 4.4.1.2. Hard disk. Dr. Nguyen Nam Hong, Le Quy Don University

  23. 4.4.1.0. Magnetic disk overview How does magnetic disk work? • Circular disc covered in magnetic coating. • R/W head reads and changes charges of magnetized particles. • Negative/Positive charges translated into binary 1’s and 0’s. • Hard disk R/W head does not touch medium surface. • Magnetic media: • Higher storage capacities. • Enclosed in sealed container to protect against physical damage. Dr. Nguyen Nam Hong, Le Quy Don University

  24. How does a Magnetic disk work? Dr. Nguyen Nam Hong, Le Quy Don University

  25. Magnetic disk terms • Physical description terms • Track - Sector • Platter - Cluster • Cylinder • Performance terms • Seek time & Access time (RPM) • Data transfer rate (bps) • Capacity (MB, GB) Dr. Nguyen Nam Hong, Le Quy Don University

  26. Magnetic disk terms Dr. Nguyen Nam Hong, Le Quy Don University

  27. Tracks and Sectors Dr. Nguyen Nam Hong, Le Quy Don University

  28. 4.4.1.1. Floppy Disk Drives • Floppy disk applications • Offline storage and backup. • File sharing and transfers. • Device driver and small application distribution. • Startup disks. • Diagnostic/antivirus disks. Dr. Nguyen Nam Hong, Le Quy Don University

  29. Floppy disk Concerns • Magnetic fields • Oil and dirt from hands • Temperature extremes Dr. Nguyen Nam Hong, Le Quy Don University

  30. Floppy Disks types • 5 ½ inch floppy disk components • Write protect notch • Hub • Index hole • Read/write access slot • 3 ½ inch floppy disk components • Write protect • Hub • High density indicator • Access cover Dr. Nguyen Nam Hong, Le Quy Don University

  31. Floppy Disk Specifications Dr. Nguyen Nam Hong, Le Quy Don University

  32. Floppy Disk Drive Problems • Floppy disk drive light stays lit • Data cable reversed • Floppy disk drives not recognized • Power or data cable not connected • BIOS needs manual configuration • General read/write failure • Improper connected data cable • Bad floppy disk • Bad floppy disk drive Dr. Nguyen Nam Hong, Le Quy Don University

  33. 4.4.1.2. Hard Disk Drives SCSI Interface • Acronym for Small Computer System Interface, a standard high-speed parallel interface defined by the X3T9.2 committee of the American National Standards Institute (ANSI). • A SCSI interface is used to connect microcomputers to SCSI peripheral devices, such as many hard disks and printers, and to other computers and local area networks. Dr. Nguyen Nam Hong, Le Quy Don University

  34. Hard Disk Drives • EIDE interface • Most common, easiest to implement • Controller built into most motherboards • Two channels supporting two devices each Dr. Nguyen Nam Hong, Le Quy Don University

  35. How Does a Hard Disk Work? Dr. Nguyen Nam Hong, Le Quy Don University

  36. Hard disk with SCSI Interface • Popular in high-end systems • SCSI adapter board must be installed • Can support combination of 7 or 15 internal or external devices • SCSI is more expensive, but more reliable and provides higher throughput rate Dr. Nguyen Nam Hong, Le Quy Don University

  37. 4.4.2. Optical disk storage 4.4.2.0. Optical disk overview. 4.4.2.1. Compact disk. 4.4.2.2. Digital Video Disk (DVD). Dr. Nguyen Nam Hong, Le Quy Don University

  38. 4.4.2.0 Optical disk overview vvvv4.4.2.0. Optical disk overview. 4.4.2.1. Compact disk. 4.4.2.2. Digital Video Disk (DVD). Dr. Nguyen Nam Hong, Le Quy Don University

  39. How does an Optical disk work? Dr. Nguyen Nam Hong, Le Quy Don University

  40. 4.4.2.1. Compact Disks • CD-ROM • CD-RW • DVD-ROM • DVD-/+RW • Most common interface is EIDE • SCSI and USB interfaces available Dr. Nguyen Nam Hong, Le Quy Don University

  41. CD-ROM Overview • Transition: change from pit to land, land to pit • Binary 1: transition present • Binary 0: transition not present • CD-R: dark dye spots in replacement of pits • Interfaces: IDE/EIDE, SCSI, USB • 1x = 150 kbps, 400 ms access rate Dr. Nguyen Nam Hong, Le Quy Don University

  42. CD Characteristics • Reliability and Durability (vs. flopply disks) • Capacity (vs. floppy disks) • Performance (exceeds HD in some cases) • Security (Read-only data) • Mixed media storage • Data, Audio, Video, Pictures • Cross platform compatibility (ISO 9660) Dr. Nguyen Nam Hong, Le Quy Don University

  43. 4.4.2.2. Digital Video Disc (DVD) • Interfaces: IDE/EIDE, USB, IEEE1394 • Can read CD/CD-R/CD-RW/CD Audio • DVD video encoded in MPEG2 format Dr. Nguyen Nam Hong, Le Quy Don University

  44. DVD Formats Dr. Nguyen Nam Hong, Le Quy Don University

  45. 4.4.3. Magnetic Tape Storage • Used almost exclusively as backup devices • Data cartridge contains a thin ribbon of Mylar plastic covered with magnetic medium • Can lose integrity after long-term continual use Dr. Nguyen Nam Hong, Le Quy Don University

  46. Tape Drives • Symptoms of data loss • Faded tape: Exposure to sunlight or humidity • Worn tape • Noise in tape mechanisms: Actual rollers and spindles in tape can wear down Dr. Nguyen Nam Hong, Le Quy Don University

  47. Tape Drives • Tape Precautions: • Do not mishandle. • Avoid temperature extremes. • Avoid magnetic fields. • Replace cartridge showing excessive wear. • Retention tapes periodically. • Refresh archive tapes annually. Dr. Nguyen Nam Hong, Le Quy Don University

  48. Tape Formats Dr. Nguyen Nam Hong, Le Quy Don University

  49. Storage Hierarchy Dr. Nguyen Nam Hong, Le Quy Don University

  50. Vocabularies (1) 1/ Cache. 2/ Compact Disks. 3/ Cylinder. 4/ DRAM. 5/ Disk surface. 6/ EEPROM. 7/ EPROM. 8/ Hard disk. 9/ Latency. 10/ Optical disks. 11/ Primary storage. Dr. Nguyen Nam Hong, Le Quy Don University

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