1.3 Outline of Command Processing

3)After the INIT that accepts the IDENTIFY message normally completes the pointer restore operation, it should make the ACK signal for the IDENTIFY message FALSE. If the ATTENTION condition does not exist when the ACK signal becomes FALSE during sending of the IDENTIFY message, the IDD regards the reconnection processing as having been normally completed and begins subsequent processing.

For further details, refer to CHANGE DEFINITION parameter list (Reselection Retry, Reselection Time-out Delay) in Section 3.1.4 and SCSI Bus (RESELECTION phase) in Chapter 1 of “SCSI Physical Interface Specifications” and SCSI Bus Error Recovery Processing in Chapter 3.

1.3.4Synchronous mode data transfer/wide mode data transfer

The IDD equips a synchronous mode data transfer function and wide mode data transfer function for processing high speed data transfers (DATA IN and DATA OUT phases) on the SCSI bus. Data transfers on the SCSI bus can be executed in any desired combination of the asynchronous mode or synchronous mode and in 8 bit widths or 16 bit widths (wide mode), but by using synchronous mode data transfer or wide mode data transfer, command processing time is shortened and throughput for input/output processing by multiple command processing using idle time on the SCSI bus can be improved.

After IDD power on, after generating a RESET condition on the SCSI bus or after one of the INITs issues a TARGET RESET message, the data transfer mode (default mode) of the IDD is the asynchronous mode. To use wide mode data transfer, the INIT must exchange a WIDE DATA TRANSFER REQUEST message or PARALLEL PROTOCOL REQUEST message with the IDD, and determine the SCSI bus width. To use the synchronous mode data transfer, the INIT must exchange the SYNCHRONOUS DATA TRANSFER REQUEST message or PARALLEL PROTOCOL REQUEST message and determine parameters necessary for executing the synchronous mode transfer. When exchange of the WIDE DATA TRANSFER REQUEST message or PARALLEL PROTOCOL REQUEST message is completed, if the synchronous mode has been established between the INIT and IDD previously, note that the asynchronous mode is set.

The INIT which uses wide mode data transfer normally sends the WIDE DATA TRANSFER REQUEST or PARALLEL PROTOCOL REQUEST message to the IDD following the IDENTIFY message after the initial SELECTION phase, and requests the TARG (IDD) to set the SCSI bus width in the wide mode. Also, if synchronous mode data transfer is used, after establishing the SCSI bus width, the INIT exchanges the SYNCHRONOUS DATA TRANSFER REQUEST message or PARALLEL PROTOCOL REQUEST message and requests the TARG (IDD) to set the synchronous data transfer mode.

The data transfer mode set with the INIT once is effective until a RESET condition occurs or until a TARGET RESET message is issued by any INITs. Therefore, in order for the INIT to avoid overhead time for message exchange, the INIT should not send the WIDE DATA TRANSFER REQUEST message and the SYNCHRONOUS DATA TRANSFER REQUEST message or PARALLEL PROTOCOL REQUEST message to the TARG each time the SELECTION phase is executed.

When the requesting synchronous mode transfer/wide mode data transfer by specifying of the CHANGE DEFINITION command (synchronous mode transfer/wide mode data transfer request) is permitted, and the IDD is maintaining the default transfer mode (asynchronous, 8-bit width), if a WIDE DATA TRANSFER REQUEST message is not sent from the INIT, the IDD enters the MESSAGE IN phase immediately after the COMMAND phase and sends the WIDE DATA TRANSFER REQUEST message to the INIT for attempting to set the 16-bit width mode. After establishing the bus width, the IDD sends the SYNCHRONOUS DATA TRANSFER REQUEST message to the INIT and attempts the synchronous mode transfer parameters (REQ/ACK offset = 127, Transfer period = 25 ns).

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Fujitsu MAP3735, MAP3367, MAP3147, MAS3735, MAS3367 specifications Synchronous mode data transfer/wide mode data transfer
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MAP3735, MAP3147, MAS3367, MAP3367, MAS3735 specifications

Fujitsu, a renowned leader in technology and innovation, has developed a variety of reliable hard disk drives (HDDs) that cater to a wide range of data storage needs. Among these, the MAS3735, MAP3367, MAS3367, MAP3147, and MAP3735 series stand out for their advanced features and exceptional performance.

The MAS3735 is a high-capacity enterprise-class drive that boasts a storage capacity of up to 300 GB. Its 10,000 RPM spindle speed ensures rapid data retrieval and efficient performance, making it ideal for data-intensive applications. It utilizes a Serial Attach SCSI (SAS) interface, which allows for improved data transfer rates and increased reliability compared to traditional SATA drives. The drive is designed with advanced technologies such as error recovery and data integrity features, ensuring the safety and security of critical data.

Similarly, the MAP3367 and MAS3367 models are geared towards both enterprise and mid-range server environments, providing a storage capacity of up to 300 GB as well. These drives also operate at a spindle speed of 15,000 RPM, offering swift access times that enhance overall system performance. The MAP3367 employs the Ultra 320 SCSI interface, allowing for significant bandwidth and ensuring data is transmitted efficiently.

On the other hand, both MAP3147 and MAP3735 models provide versatile solutions for various applications, supporting capacities from 36 GB to 147 GB. The MAP3147, with its 10,000 RPM speed, is optimized for workloads requiring quick access and high throughput, making it suitable for transactional systems and enterprise applications. The MAP3735, while offering comparable capacity, emphasizes exceptional reliability and durability, which is crucial for environments that involve heavy data loads.

All these Fujitsu HDDs are characterized by their robust construction, reliability, and efficiency. They are built to withstand heavy workloads and are equipped with features like advanced thermal management and acoustic noise reduction, ensuring they operate effectively in data center environments.

In conclusion, Fujitsu's MAS3735, MAP3367, MAS3367, MAP3147, and MAP3735 series HDDs are designed for high performance and reliability, catering to both enterprise and mid-range environments. Their advanced features make them a strong choice for businesses looking to enhance their storage solutions while maintaining data integrity and system performance.
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