Magnetic Disks - Georgia Tech - HPCA: Part 4
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Magnetic disks, such as hard drives or floppy disks, store data on platters with magnetic material on both sides, accessed by heads attached to an arm that moves together. Data is organized into tracks and sectors, with the disk's capacity calculated by the number of platters, surfaces, tracks per surface, sectors per track, and bytes per sector, requiring precise head assembly positioning due to close track spacing.
Insights
- Each magnetic disk consists of platters with magnetic material on both sides, storing data bits accessed by magnetic heads attached to an arm, showcasing a complex yet efficient storage mechanism.
- The organization of data on magnetic disks into tracks, forming cylinders with sectors as the smallest readable units, highlights a meticulous design that maximizes storage capacity through the precise calculation of disk capacity based on various factors like platters, surfaces, tracks, sectors, and bytes per sector.
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Recent questions
How are data bits stored on magnetic disks?
Data bits on magnetic disks are stored on platters with magnetic material on both sides. These platters are attached to a spindle that rotates at the same speed due to a motor. Magnetic heads, attached to an arm that moves in unison, access the data bits stored on all surfaces of the platters.
What is the organization of data on magnetic disks?
Data on magnetic disks is organized into tracks, forming cylinders with tracks at the same distance from the spindle accessible by different heads simultaneously. Sectors, the smallest readable units, contain data bits, a checksum, and other necessary information. The disk capacity is calculated by the number of platters, surfaces, tracks per surface, sectors per track, and bytes per sector.
How many platters do magnetic disks typically have?
Magnetic disks typically have a small number of platters, with each platter having magnetic material on both sides. These platters are attached to a spindle that rotates at the same speed due to a motor. The entire disk is thin and compact, usually around two and a half inches wide.
What is the size of sectors on magnetic disks?
Sectors on magnetic disks are typically kilobyte-sized and contain data bits, a checksum, and other necessary information. The disk capacity is calculated by the number of platters, surfaces, tracks per surface, sectors per track, and bytes per sector.
Why is precise head assembly positioning important on magnetic disks?
The close spacing of tracks on magnetic disks requires precise head assembly positioning. Magnetic heads, attached to an arm that moves in unison, access data bits stored on all surfaces of the platters. This precise positioning ensures accurate reading and writing of data on the disk.
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Summary
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Magnetic Disk Structure and Organization
- Magnetic disks, like hard drives or floppy disks, consist of platters attached to a spindle that rotate at the same speed due to a motor. Each platter has magnetic material on both sides, with data bits stored on all surfaces, accessed by magnetic heads attached to an arm that moves in unison.
- Data on magnetic disks is organized into tracks, forming cylinders with tracks at the same distance from the spindle accessible by different heads simultaneously. Sectors, the smallest readable units, contain data bits, a checksum, and other necessary information, with the disk capacity calculated by the number of platters, surfaces, tracks per surface, sectors per track, and bytes per sector.
- Magnetic disks typically have a small number of platters, thousands of tracks per surface, tens to hundreds of sectors per track, and kilobyte-sized sectors. The close spacing of tracks requires precise head assembly positioning, with the entire disk being thin and compact, usually around two and a half inches wide.
