Tutorial 5
Device Management
Magnetic Disk
Description:
- A memory device consisting of a flat disk covered with a magnetic coating on which information is stored.
- Magnetically recorded and can be re-recorded over and over.
- Disks are rotating platters with a mechanical arm that moves a read/write head between the outer and inner edges of the platter's surface.
Advantage:
- Can rapidly retrieve information from any part of a magnetic disk without regard for the order in which the information was recorded
- The use of a CrNi pre-seed layer reduces usage of high cost RuAl, improves coercivity and maintains a good SNR.
- The use of a relatively thick CrNi pre-seed layer improves the thermal erasure problems related to a glass disk medium.
Example:
- floppy disk
- hard disk
Image
:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikLQaZREfk2gfeGD0acjOPH-CeBGmQVdv7yHp0oBSnIXSnhLisbzsN1J5rUR0DHr3-WrGaufIZDtHtAhaY_RnKP7mNF42TsPx8df01KZC2De8QtsZYJ2GFfWcO7IHRrzbIFxL4In51Ubg/s320/diskinside.jpg)
Device Management
Magnetic Disk
Description:
- A memory device consisting of a flat disk covered with a magnetic coating on which information is stored.
- Magnetically recorded and can be re-recorded over and over.
- Disks are rotating platters with a mechanical arm that moves a read/write head between the outer and inner edges of the platter's surface.
Advantage:
- Can rapidly retrieve information from any part of a magnetic disk without regard for the order in which the information was recorded
- The use of a CrNi pre-seed layer reduces usage of high cost RuAl, improves coercivity and maintains a good SNR.
- The use of a relatively thick CrNi pre-seed layer improves the thermal erasure problems related to a glass disk medium.
Example:
- floppy disk
- hard disk
Image
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3-xnJaPfRP-PwWdDUO9V8UK-gfwWdL0jlT_KsUD3TYvw61BQ6EYTYEhJ5VPYHUAzbBHsC0RvMp6d2Buhnp19iBV0Kl_5yTKxmbQwZo6BTD0k_aiAfUBbZTvKpa31lApB44p5op0RvIl8/s320/diskette.png)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikLQaZREfk2gfeGD0acjOPH-CeBGmQVdv7yHp0oBSnIXSnhLisbzsN1J5rUR0DHr3-WrGaufIZDtHtAhaY_RnKP7mNF42TsPx8df01KZC2De8QtsZYJ2GFfWcO7IHRrzbIFxL4In51Ubg/s320/diskinside.jpg)
Optical Disk (Laser Disk)
Description:
- A flat, circular, plastic-coated disk that stores digital data, such as music or text, as tiny pits etched into the surface and is read with a laser scanning the surface.
- Provided with a land region and a groove region that are
formed on a substrate, the land region and groove region being used as a
recording track that is the medium of the recording/playback of
information signal, and a pre-pit region that is formed at the boundary
part of neighboring land region and groove region and is disposed every
other boundary part, the pre-pit region including specific information
Advantage:
- Offers stable header detection and address identification.
- Enhances the stability of playback/ recording at data region
- Has higher capacities as removable cartridges
- Not subject to head crashes or corruption from stray magnetic fields
- Has a 30-year life and is less vulnerable to extremes of hot and cold.
Example:
- CDs
- CD-ROMs
- DVD-ROMs
Image:![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibcp2Z7p2E95Bl909KWHmP-LniFGor4YUmacpDxQoLCkv9CFhXHNEWwdIxe_l9n1NGhGGDNO2p_uZUd3ja4q4_gtvSLRBl9ATryZHUd2pBiOgvAZ9mqHXfi7tO3hIe6-FpeUIEm_5tnrc/s320/ist2_337562-cd-compact-disk-in-color.jpg)
Description:
- A flat, circular, plastic-coated disk that stores digital data, such as music or text, as tiny pits etched into the surface and is read with a laser scanning the surface.
- Provided with a land region and a groove region that are
formed on a substrate, the land region and groove region being used as a
recording track that is the medium of the recording/playback of
information signal, and a pre-pit region that is formed at the boundary
part of neighboring land region and groove region and is disposed every
other boundary part, the pre-pit region including specific information
Advantage:
- Offers stable header detection and address identification.
- Enhances the stability of playback/ recording at data region
- Has higher capacities as removable cartridges
- Not subject to head crashes or corruption from stray magnetic fields
- Has a 30-year life and is less vulnerable to extremes of hot and cold.
Example:
- CDs
- CD-ROMs
- DVD-ROMs
Image:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibcp2Z7p2E95Bl909KWHmP-LniFGor4YUmacpDxQoLCkv9CFhXHNEWwdIxe_l9n1NGhGGDNO2p_uZUd3ja4q4_gtvSLRBl9ATryZHUd2pBiOgvAZ9mqHXfi7tO3hIe6-FpeUIEm_5tnrc/s320/ist2_337562-cd-compact-disk-in-color.jpg)
Flash Memory
Description:
- A computer chip with a read-only memory that retains its data when the power is turned off and can be electronically erased and reprogrammed without being removed from the circuit board
- non-volatile computer memory
Advantage:
- Lower power consumption as compared to a hard drive
- better kinetic shock resistance than hard disk
- Offers fast read access times
- High reliability.
- Small and can be carried easily
- Higher speed in erasing and repairing the memory cell array
- Provides a new decoder circuit for a memory array which significantly reduces the breakdown voltage requirement of the devices in the decoder
Example:
- memory card
- thumbdrive
- memory stick
Image:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnqQ3b3IFf1WK0U2Pmhwd_macM5a69flAy7TFlu5rzySOrfkYhMHEP8I_99P724fK3Se1UQnjJsDyoOEfHpfCL0Z0dGTfrR6TFRXkv0Z-KLxGesUFWbCmG16ys_a8_G7b3av2H8zeQKq4/s320/usb_flash_memory_key.png)
Description:
- A computer chip with a read-only memory that retains its data when the power is turned off and can be electronically erased and reprogrammed without being removed from the circuit board
- non-volatile computer memory
Advantage:
- Lower power consumption as compared to a hard drive
- better kinetic shock resistance than hard disk
- Offers fast read access times
- High reliability.
- Small and can be carried easily
- Higher speed in erasing and repairing the memory cell array
- Provides a new decoder circuit for a memory array which significantly reduces the breakdown voltage requirement of the devices in the decoder
Example:
- memory card
- thumbdrive
- memory stick
Image:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnqQ3b3IFf1WK0U2Pmhwd_macM5a69flAy7TFlu5rzySOrfkYhMHEP8I_99P724fK3Se1UQnjJsDyoOEfHpfCL0Z0dGTfrR6TFRXkv0Z-KLxGesUFWbCmG16ys_a8_G7b3av2H8zeQKq4/s320/usb_flash_memory_key.png)
Magneto-optical Disk
Description:
- A kind of optical disc capable of writing and rewriting data
- Use either magneto-optic (MO) or phase change technology
- Appears as hard drive to the operating system and do not require a special file system
- Extremely robust
- Comprises a substrate and a magneto-optical recording layer applied over the substrate. The magneto-optical disc further comprises an overcoat layer applied over the recording layer having a thickness in a range between 25 nanometers and 200 microns, wherein data is recorded on the magneto-optical disc and read from the magneto-optical disc using a laser light that is incident on the overcoat layer.
Advantage:
- Lower cost consumer-oriented product
- Rewritable
- Data or sound may be recorded to and erased from any portion of a magneto-optical disk multiple times
Example:
- WORM (Write Once/ Read Many) disk
- Recordable MiniDisc
Image:![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsaKyHOF8nFjc1X79SC27LkpjwKTM72ZOsQtxcMw8PE9sqSjXgtt9VT5j79pHzcQj3Ax7_Q8aF1flwhCplr3bfEmQjDfjz9Jv6O4yTObE2yW7HXWsBNPrqd58mEj3Ub2oV5s9k4h-gIzw/s320/HW_39243.gif)
Description:
- A kind of optical disc capable of writing and rewriting data
- Use either magneto-optic (MO) or phase change technology
- Appears as hard drive to the operating system and do not require a special file system
- Extremely robust
- Comprises a substrate and a magneto-optical recording layer applied over the substrate. The magneto-optical disc further comprises an overcoat layer applied over the recording layer having a thickness in a range between 25 nanometers and 200 microns, wherein data is recorded on the magneto-optical disc and read from the magneto-optical disc using a laser light that is incident on the overcoat layer.
Advantage:
- Lower cost consumer-oriented product
- Rewritable
- Data or sound may be recorded to and erased from any portion of a magneto-optical disk multiple times
Example:
- WORM (Write Once/ Read Many) disk
- Recordable MiniDisc
Image:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsaKyHOF8nFjc1X79SC27LkpjwKTM72ZOsQtxcMw8PE9sqSjXgtt9VT5j79pHzcQj3Ax7_Q8aF1flwhCplr3bfEmQjDfjz9Jv6O4yTObE2yW7HXWsBNPrqd58mEj3Ub2oV5s9k4h-gIzw/s320/HW_39243.gif)
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