User manual SEAGATE DIAMONDMAX VL 20

[. . . ] DiamondMax VL 20 92041U4, 91531U3 and 91021U2 ® Part #1427/A All material contained herein Copyright © 1999 Maxtor Corporation. MaxFaxTM is a trademark of Maxtor Corporation. DiamondMax®, Maxtor® and No Quibble® Service are registered trademarks of Maxtor Corporation. Other brands or products are trademarks or registered trademarks of their respective holders. [. . . ] (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. Before the Set Multiple Mode command has been executed, or 2. When Read Multiple commands are disabled. 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. The drives support block sizes of 2, 4, 8 and 16 sectors. 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. [. . . ] Whitney technology A method of constructing a read/write head in a rigid disk drive using a Whitney head. In all other details it is the same as Winchester technology. Winchester head The read/write head used in Winchester technology, non-removable media disk drives. May be either a monolithic or composite type. [. . . ]