User manual SEAGATE DIAMONDMAX 6800

[. . . ] HA RD DRIVE P RO D UC T MA N UA L DiamondMaxTM 6800 92720U8, 92040U6, 91700U5 91360U4, 91020U3, 90845U3 and 90650U2 DiamondMaxTM 6800 92720U8, 92040U6, 91700U5, 91360U4, 91020U3, 90845U3 and 90650U2 Part #1416 All material contained herein Copyright © 1999 Maxtor Corporation. DiamondMaxTM, DiamondMaxTM 4320, DiamondMaxTM 6800, DiamondMaxTM Plus 5120 and MaxFaxTM are trademarks of Maxtor Corporation. No Quibble® Service is a registered trademark of Maxtor Corporation. Other brands or products are trademarks or registered trademarks of their respective holders. [. . . ] Several sectors are transferred to the host as a block, without intervening interrupts. DRQ qualification of the transfer is required only at the start of each block, not of each sector. The block count consists of the number of sectors to be transferred as a block. (The block count is programmed by the Set Multiple Mode command, which must be executed prior to the Read Multiple command. ) READ LONG command is limited to single sector requests. When the Read Multiple command is issued, the Sector Count register contains the number of sectors requested -- not the number of blocks or the block count. If the number of sectors is not evenly divisible by the block count, as many full blocks as possible are transferred, followed by a final, partial block transfer. This final, partial block transfer is for N sectors, where N = (sector count) modulo (block count) The Read Multiple operation will be rejected with an Aborted Command error if attempted: 1. The controller reports disk errors encountered during Read Multiple commands at the start of the block or partial block transfer. However, DRQ still sets, and the transfer occurs normally, along with the transfer of any corrupt data. Remaining block data from the following the sector in error is not valid. If the Sector Count register contains 0 when the Set Multiple Mode command is issued, Read Multiple and Write Multiple commands are disabled; no error is returned. Once the appropriate action has been taken, the controller resets BSY and generates an interrupt. At power up, or after a hardware or software reset, Read Multiple and Write Multiple commands are disabled by default. 7­3 INTERFACE COMMANDS Set Multiple Mode Enables the controller to perform Read and Write Multiple operations, and establishes the block count for these commands. Before issuing this command, the Sector Count register should be loaded with the number of sectors per block. When this command is received, the controller sets BSY and examines the Sector Count register contents. If they contain a valid and supported block count value, that value is loaded for all subsequent Read and Write Multiple commands, and execution of those commands is enabled. An invalid and unsupported block count in the register results in an Aborted Command error and disallows Read Multiple and Write Multiple commands. Write Commands Write Sector(s) Writes from 1 to 256 sectors, beginning at a sector specified in the Command Block. (A sector count of 0 requests 256 sectors. ) When the Command register is written, the drive sets the DRQ bit and waits for the host to fill the sector buffer with the data to be written. An interrupt is not generated to start the first buffer fill operation. Once the buffer is full, the drive resets DRQ, sets BSY, and begins command execution. If the drive is not already on the desired track, an implied seek is performed. The data loaded in the buffer is written to the data field of the sector, followed by the ECC bytes. [. . . ] SEEK COMPLETE SIGNAL A digital signal level which indicates that the positioner is not moving and is located over a cylinder or offset position. SEEK TIME The amount of time between when a step pulse or seek command is issued until the head settles onto the desired cylinder. SEQUENTIAL ACCESS The writing or reading of data in a sequential order such as reading data blocks stored one after the other on magnetic tape. SERVO BURST A momentary servo pattern used in embedded servo control systems usually positioned between sectors or at the end of a track. [. . . ]