Conference title
Click here, type the title of your paper, Capitalize first letter
First Authora, Second Authorb, Third Authora,b,* aFirst affiliation, Address, City and Postcode, Country bSecond affiliation, Address, City and Postcode, Country
Abstract
Magnetic and optical disk control share a number of similarities and differences. This leads to a number of issues unique to each kind of disk. These issues and the other properties in general, of the control and servo-mechanical systems of hard disks (magnetic) and optical disks are explained in this paper.
Keywords: magnetic, optical, control mechanism, servo mechanical, disk control
1. Introduction
Magnetic and optical disk control share a lot of common features like using spinning media …show more content…
2. A Summary of Similarities and Dissimilarities
A summary of the similarities and differences between magnetic and optical disks is shown in the table below.
Magnetic disk Optical Disk
Contains multiple fixed disks Usually a single removable disk
Has excellent drive mechanics Has somewhat mediocre drive mechanics
Position error signals have a tolerable SNR, and are multiplexed with data Position error signals have very good SNR and are always available
Has a low to medium sample rate Has a high sample rate
Vertical positioning is done with air bearings, near field, no focus loop with multiple small heads Vertical positioning is done without air bearings, with far field focus loop having a single large head
Has a single medium to high frequency tracking loop Has low and high frequency tracking loops
Spindle loop is low frequency Spindle loop is low frequency
Spindle mode is CAV (Constant Angular Velocity) Spindle mode is CLV (Constant Linear Velocity)
Has circular tracks Tracks are mostly spiral, some are circular
Has mostly random access applications Is used mainly in file …show more content…
Comparison of Spindle Control
Both the optical and magnetic disks have relatively low frequency spindle control loops. In magnetic disks, this control loop is responsible for controlling the air flow over the disk, which ensures correct flying height of the head. This is not of concern in optical recording.
Optical disks usually operate in Constant Linear Velocity mode, especially when they contain streaming media like audio or video. This mode is used to optimize the amount of data that can be stored on a disk surface, but it also requires the spindle to adapt different speeds as the head moves across diameters of the disk. For random access, which is more common in computer applications, the time taken to ramp up the spindle in CLV mode is large and is prohibitive. So most optical disks use CAV mode (or zoned CAV mode which helps keep constant speed of spindle over larger disk regions).
5. Comparison of disk structure and
Click here, type the title of your paper, Capitalize first letter
First Authora, Second Authorb, Third Authora,b,* aFirst affiliation, Address, City and Postcode, Country bSecond affiliation, Address, City and Postcode, Country
Abstract
Magnetic and optical disk control share a number of similarities and differences. This leads to a number of issues unique to each kind of disk. These issues and the other properties in general, of the control and servo-mechanical systems of hard disks (magnetic) and optical disks are explained in this paper.
Keywords: magnetic, optical, control mechanism, servo mechanical, disk control
1. Introduction
Magnetic and optical disk control share a lot of common features like using spinning media …show more content…
2. A Summary of Similarities and Dissimilarities
A summary of the similarities and differences between magnetic and optical disks is shown in the table below.
Magnetic disk Optical Disk
Contains multiple fixed disks Usually a single removable disk
Has excellent drive mechanics Has somewhat mediocre drive mechanics
Position error signals have a tolerable SNR, and are multiplexed with data Position error signals have very good SNR and are always available
Has a low to medium sample rate Has a high sample rate
Vertical positioning is done with air bearings, near field, no focus loop with multiple small heads Vertical positioning is done without air bearings, with far field focus loop having a single large head
Has a single medium to high frequency tracking loop Has low and high frequency tracking loops
Spindle loop is low frequency Spindle loop is low frequency
Spindle mode is CAV (Constant Angular Velocity) Spindle mode is CLV (Constant Linear Velocity)
Has circular tracks Tracks are mostly spiral, some are circular
Has mostly random access applications Is used mainly in file …show more content…
Comparison of Spindle Control
Both the optical and magnetic disks have relatively low frequency spindle control loops. In magnetic disks, this control loop is responsible for controlling the air flow over the disk, which ensures correct flying height of the head. This is not of concern in optical recording.
Optical disks usually operate in Constant Linear Velocity mode, especially when they contain streaming media like audio or video. This mode is used to optimize the amount of data that can be stored on a disk surface, but it also requires the spindle to adapt different speeds as the head moves across diameters of the disk. For random access, which is more common in computer applications, the time taken to ramp up the spindle in CLV mode is large and is prohibitive. So most optical disks use CAV mode (or zoned CAV mode which helps keep constant speed of spindle over larger disk regions).
5. Comparison of disk structure and