Theory of Device Operation

4.1 Outline

This chapter consists of two parts. First part (Section 4.2) explains mechanical assemblies of the disk drive. Second part (Sections 4.3 through 4.7) explains a servo information recorded in the disk drive and drive control method.

4.2 Subassemblies

The disk drive consists of a disk enclosure (DE) and printed circuit assembly (PCA).

The DE contains all movable parts in the disk drive, including the disk, spindle, actuator, read/write head, and air filter. For details, see Subsections 4.2.1 to 4.2.4.

The PCA contains the control circuits for the disk drive. The disk drive has one PCA. For details, see Sections 4.3.

4.2.1 Disk

The DE contains disks with an outer diameter of 65 mm and an inner diameter of 20 mm.

Servo data is recorded on each cylinder (total 172). Servo data written at factory is read out by the read head. For servo data, see Section 4.7.

4.2.2 Spindle

The spindle consists of a disk stack assembly and spindle motor. The disk stack assembly is activated by the direct drive sensor-less DC spindle motor, which has a speed of 4,200 rpm ±1%. The spindle is controlled with detecting a PHASE signal generated by counter electromotive voltage of the spindle motor at starting.

4.2.3 Actuator

The actuator consists of a voice coil motor (VCM) and a head carriage. The VCM moves the head carriage along the inner or outer edge of the disk. The head carriage position is controlled by feeding back the difference of the target position that is detected and reproduced from the servo information read by the read/write head.

4-2

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Fujitsu MHW2060AC, MHW2040AC manual Outline, Subassemblies, Disk, Spindle, Actuator
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MHW2060AC, MHW2040AC specifications

The Fujitsu MHW2040AC and MHW2060AC are notable hard disk drives (HDDs) that have been widely used in various computing applications, especially in laptops and compact devices. These models are part of Fujitsu's commitment to providing reliable storage solutions that meet the demands of modern computing.

The MHW2040AC offers a storage capacity of 40 GB, while the MHW2060AC provides a slightly larger capacity at 60 GB. This range of storage makes both models suitable for users looking for dependable space for documents, multimedia files, and software applications. Both drives utilize a 2.5-inch form factor, ideal for mobile computing, as they are lightweight and designed to fit into space-constrained environments.

In terms of performance, both drives operate at a spindle speed of 5400 RPM. This speed strikes a balance between power consumption and performance, making these drives an efficient choice for everyday tasks, such as web browsing and office applications. The drives are equipped with an interface of Ultra ATA/133, which enables faster data transfer rates compared to older models, thereby enhancing overall system responsiveness.

The MHW2040AC and MHW2060AC also incorporate several advanced technologies to bolster their performance and reliability. One such feature is the use of a fluid dynamic bearing (FDB) for the spindle motor, which minimizes noise and vibration, thus improving the overall user experience. Additionally, both drives come with error correction technology that helps maintain data integrity by detecting and correcting errors during read and write operations.

Moreover, these HDDs feature a shock sensor that can detect sudden movements, allowing the drive to park its heads to prevent data loss and hardware damage. This is particularly beneficial in mobile environments where the risks of impact are higher.

Both the MHW2040AC and MHW2060AC are designed with energy-saving features, making them an environmentally responsible choice for energy-conscious consumers. Their low power consumption not only contributes to a reduced carbon footprint but also extends battery life for portable devices.

In summary, the Fujitsu MHW2040AC and MHW2060AC are reliable, efficient, and user-friendly hard disk drives that combine moderate capacities with advanced features designed to enhance performance, ensure data integrity, and extend device longevity. These drives are well-suited for a range of applications, making them a solid choice for users seeking dependable storage solutions.
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