Fujitsu MBA3073NP User Manual download pdf (Page 19)

(5) High speed data transfer

Such a high data transfer rate on the SCSI bus can be useful with the large capacity buffer in the

HDD.

• 8-bit SCSI: The data transfer rate on the SCSI bus is 40 MB/s maximum at the

synchronous mode.

• 16-bit SCSI: The data transfer rate on the SCSI bus is 320 MB/s maximum at the paced

transfer synchronous mode.

Note:

The maximum data transfer rate in asynchronous mode may be limited by the response time of

initiator and the length of SCSI bus length. The maximum data transfer rate in synchronous

mode may be limited by the cable length, transmission characteristics of the SCSI bus and the

connected SCSI device number.

(6) Continuous block processing

The addressing method of data blocks is logical block address. The initiator can access data by

specifying block number in a logically continuous data space without concerning the physical

structure of the track or cylinder boundaries.

The continuous processing up to [64K-1] blocks in a command can be achieved, and the HDD can

perform continuous read/write operation when processing data blocks on several tracks or cylinder.

(7) Multi-segment data buffer

The data buffer is 8M bytes. Data is transferred between SCSI bus and disk media through this

data buffer. This feature provides the suitable usage environment for users.

Since the initiator can control the disconnect/reconnect timing on the SCSI bus by specifying the

condition of stored data to the data buffer or empty condition of the data buffer, the initiator can

perform the effective input/output operations with utilizing high data transfer capability of the

SCSI bus regardless of actual data transfer rate of the disk drive.

(8) Cache feature

After executing the READ command, the HDD reads automatically and stores (prefetches) the

subsequent data blocks into the data buffer (Read-ahead caching).

The high speed sequential data access can be achieved by transferring the data from the data buffer

without reaccessing the disk in case the subsequent command requests the prefetched data blocks.

The write cache feature is supported. When this feature is enabled, the status report is issued without

waiting for completion of write processing to disk media, thereby enabling high speed write

processing.

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Fujitsu MBA3073NP User Manual Page 19