5.3 Host Commands

The implementation of the READ MULTIPLE command is identical to that of the READ SECTOR(S) command except that the number of sectors is specified by the SET MULTIPLE MODE command are transferred without intervening interrupts. In the READ MULTIPLE command operation, the DRQ bit of the Status register is set only at the start of the data block, and is not set on each sector.

The number of sectors (block count) to be transferred without interruption is specified by the SET MULTIPLE MODE command. The SET MULTIPLE MODE command should be executed prior to the READ MULTIPLE command.

When the READ MULTIPLE command is issued, the Sector Count register contains the number of sectors requested (not a number of the block count or a number of sectors in a block).

Upon receipt of this command, the device executes this command even if the value of the Sector Count register is less than the defined block count (the value of the Sector Count should not be 0).

If the number of requested sectors is not divided evenly (having the same number of sectors [block count]), as many full blocks as possible are transferred, then a final partial block is transferred. The number of sectors in the partial block to be transferred is n where n = remainder of (“number of sectors”/”block count”).

If the READ MULTIPLE command is issued before the SET MULTIPLE MODE command is executed or when the READ MULTIPLE command is disabled, the device rejects the READ MULTIPLE command with an ABORTED COMMAND error.

If an unrecoverable error occurs, reading sector is stopped at the sector where the error occurred. Command block registers contain the cylinder, the head, the sector addresses (in the CHS mode) or the logical block address (in the LBA mode) of the sector where the error occurred, and remaining number of sectors that had not transferred after the sector where the error occurred.

An interrupt is generated when the DRQ bit is set at the beginning of each block or a partial block.

Figure 5.2 shows an example of the execution of the READ MULTIPLE command.

Block count specified by SET MULTIPLE MODE command = 4 (number of sectors in a block)

READ MULTIPLE command specifies;

Number of requested sectors = 9 (Sector Count register = 9)

Number of sectors in incomplete block = remainder of 9/4 =1

C141-E104-02EN

5-19

Page 96
Image 96
Fujitsu MHM200AT, MHM2100AT, MHM215OAT, MHL2300AT manual Host Commands

MHM215OAT, MHM200AT, MHL2300AT, MHM2100AT specifications

Fujitsu, a leader in storage technology, has developed a range of hard disk drives designed for reliability and performance, catering to both enterprise and consumer needs. The Fujitsu MHM2100AT, MHL2300AT, MHM200AT, and MHM215OAT models are part of this impressive lineup, showcasing various features and technologies that set them apart.

The MHM2100AT model is known for its 2.5-inch form factor, offering a storage capacity of 100GB. It operates at a speed of 5400 RPM, which balances performance and power efficiency. The drive utilizes ATA-6 interface (Parallel ATA) ensuring compatibility with a wide range of systems. One of its primary features is the advanced cache memory architecture, which allows for quicker access to frequently used data. This enhances overall system performance while preserving energy consumption.

The MHL2300AT provides a step up, with its 300GB of capacity. It also maintains a 5400 RPM speed and is designed for optimal heat dissipation and durability. This model is particularly suited for mobile computing applications due to its lightweight design and low power requirements. The MHL2300AT also integrates a sophisticated error correction code (ECC) technology, enhancing data integrity during storage and retrieval processes.

Moving on to the MHM200AT, this unit provides substantial storage of 200GB, maintaining a similar 5400 RPM speed. What sets the MHM200AT apart is its focus on data security with Built-in Security Features such as disk encryption capabilities. This model is suitable for professionals dealing with sensitive information, ensuring both performance and protection against data breaches.

Lastly, the MHM215OAT, another key model, balances user-friendly design with performance metrics. It offers a generous 150GB capacity and features an enhanced seek time for quick file access. With its emphasis on reliability, the MHM215OAT is often utilized in environments where uptime is critical, such as in commercial servers or high-performance workstations.

In conclusion, Fujitsu's MHM2100AT, MHL2300AT, MHM200AT, and MHM215OAT each possess unique features and technologies that cater to diverse user needs. Their combination of efficient power consumption, enhanced data integrity, and reliability make them compelling choices for businesses and individuals alike. Whether for mobile devices, personal computing, or enterprise applications, these models continue to exemplify Fujitsu's commitment to quality and performance in storage solutions.