1.3 Outline of Command Processing

(2)Basic disconnect processing procedure

Disconnect processing is executed basically by the following processing procedure.

1)If the IDD judges that it is possible for it to disconnect from the SCSI bus during execution of a command, it sends a DISCONNECT message to the INIT and enters the BUS FREE phase. At this time, if necessary, the IDD sends a message to activate a pointer in the INIT which precedes sending of the DISCONNECT message. Furthermore, for details concerning pointers, refer to the SCSI pointer description in “SCSI Physical Interface Specifications” and “Chapter 2 SCSI Messages.”

2)After the IDD enters the BUS FREE phase, it is possible for the INIT to issue other commands. Also, it is possible for an IDD which has performed disconnect processing to receive input/output operation requests from each INIT (this is explained in the description of the command queuing function in Section 1.4).

3)The IDD executes the command which performs disconnect processing internally.

4)After that, the IDD executes reconnection processing at the point, when it is necessary for operation on the SCSI bus, to reconnect with the INIT (See item (6) concerning reconnection processing).

(3)Disconnect processing procedure after COMMAND phase execution

If commands are queued (see Section 1.4), disconnect processing is performed immediately after the COMMAND phase execution is completed. In this case, the IDD switches from the COMMAND phase to the MESSAGE IN phase and sends the DISCONNECT message to the INIT.

(4)Disconnect processing procedure after data transfer execution

For commands which accompany a data transfer, disconnect processing may be performed during DATA IN or DATA OUT phase execution or after transfer of the last data is completed. In this case, caution is necessary when executing the following types of pointer controls.

a.If disconnecting during a data transfer

In cases where data transfer has begun (in DATA IN or DATA OUT phase) and it will take time until transfer of subsequent data can be transferred (example: When the data buffer has been emptied by a READ command, or the data buffer has ceased to be empty due to a WRITE command), disconnect processing is performed during data transfer. In this case, the IDD sends the SAVE DATA POINTER message before sending the DISCONNECT message. When the INIT receives the SAVE DATA POINTER message, it must save the current value of the current data pointer and make it possible to transfer data from the subsequent data at reconnection time.

b.If disconnecting after the final data transfer is completed

In the case of a disconnect after transfer of all the data necessary for execution of a command has been completed normally, (example: a WRITE command), the IDD sends a DISCONNECT message after sending the SAVE DATA POINTER message.

After that, the IDD executes reconnection processing and enters the STATUS phase immediately and reports the status byte without requesting a data transfer.

C141-E167

1 - 13

Page 30 Page 32
Page 31
Image 31
Fujitsu MAP3147, MAP3367, MAS3735, MAP3735, MAS3367 specifications Outline of Command Processing
Page 30 Page 32

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.
Top Page Image Contents