Data Format

A number starting with 0 is assigned to each cylinder required in the user space in ascending order. If the number of cylinders do not reach the maximum, the rest of the cylinders will not be used.

Always one cylinder that is located at the end of each zone in the user space can be established as an alternate cylinder. Alternate cylinders will be used for alternate blocks when primary cylinders in the user space are used up. See Subsections 3.1.2 and 3.3.2 for details.

(2)Internal test space

The Internal test space is an area for diagnostic purposes only and its data block length is always 512KByte. The Internal test space consists of 8 cylinders and outer-host cylinder is always assigned. The user cannot change the number of cylinders in the Internal test space or their positions.

(3)System space

The system space is an area for exclusive use of the IDD itself and the following information are recorded.

Defect list (P list and G list)

MODE SELECT parameter (saved value)

Statistical information (log data)

Controller control information

The above information is duplicated in several different locations for safety.

Note:

The system space is also called SA space.

3.1.2Alternate spare area

The alternate spare area consists of the last track of each cell in the user space and an alternate cylinder allocated to the last cylinder of each zone.

The spare area in each cylinder is placed at the end of the last track as shown in Figure 3.2. These spare sectors are located in the end of the track logically, not necessarily located at the end physically because of track skew or cylinder skew. (Details are explained on Subsection 3.1.3.)

Size can be specified by the MODE SELECT command.

The number of spare sectors per cell can be specified exceeding 32. The default for the spare sectors number is 84.

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Fujitsu MAP3147FC, MAP3735FC manual Alternate spare area

MAP3735FC, MAP3147FC specifications

Fujitsu has been a prominent player in the hard disk drive market, with its MAP3147FC and MAP3735FC models standing out in terms of performance and reliability. These drives are engineered to meet the growing demands of enterprise applications, providing robust solutions for data storage in critical environments.

The Fujitsu MAP3147FC, with a capacity of 147 GB, is optimized for high-speed data access and storage efficiency. This 3.5-inch SCSI drive operates at a rotational speed of 15,000 RPM, ensuring rapid data retrieval and minimized latency, making it ideal for applications requiring quick transaction processing. It features a 4 Gbps Fibre Channel interface, which enhances connectivity and system integration, promoting seamless communication between devices in storage area networks.

On the other hand, the MAP3735FC model offers a higher capacity of 300 GB. It shares similar specifications with its counterpart, including the 15,000 RPM speed, which guarantees top-notch performance for mission-critical applications. The MAP3735FC, like the MAP3147FC, incorporates advanced technologies such as Command Queuing, which optimizes the execution of multiple read and write commands in a queue. This feature is particularly beneficial in environments with high I/O demands, improving overall system throughput and efficiency.

Both drives utilize sophisticated error correction techniques, ensuring data integrity and reliability. They are equipped with features like S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology), which continuously monitors the health of the drives and helps predict potential failures, allowing for proactive maintenance and data protection.

In terms of physical characteristics, both models are designed to withstand the rigors of continuous operation. They are built with a rugged casing to protect against vibration and shock, making them suitable for use in enterprise-level servers and storage systems. Their design also allows for efficient heat dissipation, which is critical for maintaining optimal performance during extended use.

In summary, Fujitsu's MAP3147FC and MAP3735FC hard drives embody a combination of high speed, reliability, and advanced features tailored for enterprise environments. Their robust performance, large storage capacities, and reliable error correction technologies make them an excellent choice for businesses looking to optimize their data storage solutions and ensure seamless operation in demanding applications. With Fujitsu's commitment to quality and innovation, these models continue to meet the evolving needs of the data storage industry.