07 External Memory - MetaLab
07 External Memory - MetaLab 07 External Memory - MetaLab
Timing of Disk I/O Transfer•Seek time- Moving head to correct track•(Rotational) latency/delay-Waiting for data to rotate underhead•Access time = Seek + Latency•Transfer rate-the time required for the transfer data
Optical Storage CD-ROM• Originally for audio• 650Mbytes giving over 70 minutes audio• The disk is formed from a resin such as polycarbonate.• Record data digitally (music/computer data)• Data recorded as a series of microscopic pits on thesurface of the polycarbonate.• How?▫ By using high-intensity laser to create a master disk▫ The master is used to make a die to stamp out copies ontopolycarbonate▫ The pitted surface is then coated with a highly reflectivesurface such as aluminium or gold▫ This shiny surface is protected against dust and scratchesby suing a top coat of clear acrylic▫ Finally a label can be silkscreened onto the acrylic
- Page 1 and 2: William StallingsComputer Organizat
- Page 3 and 4: Magnetic Disk• Disk - a circular
- Page 5 and 6: Inductive Write MR Read
- Page 7 and 8: Disk Data Layout
- Page 9 and 10: Disk Layout Methods Diagram
- Page 11 and 12: Multiple zone recording (MZR)• To
- Page 13 and 14: Removable or Not• Removable disk
- Page 15 and 16: Multiple Platters
- Page 17 and 18: Classification of disk based on hea
- Page 19: Disk performance parameters• The
- Page 23 and 24: Continue..• Data on CD/CD-Rom is
- Page 25 and 26: Other Optical Storage• CD-Recorda
- Page 27 and 28: DVD - technology• Multi-layer•
- Page 29 and 30: Magnetic Tape• Tape system use th
Optical Storage CD-ROM• Originally for audio• 650Mbytes giving over 70 minutes audio• The disk is formed from a resin such as polycarbonate.• Record data digitally (music/computer data)• Data recorded as a series of microscopic pits on thesurface of the polycarbonate.• How?▫ By using high-intensity laser to create a master disk▫ The master is used to make a die to stamp out copies ontopolycarbonate▫ The pitted surface is then coated with a highly reflectivesurface such as aluminium or gold▫ This shiny surface is protected against dust and scratchesby suing a top coat of clear acrylic▫ Finally a label can be silkscreened onto the acrylic
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