Datasheet

Read Long (w/ and wo/ retry)
This command is similar to the Read Sectors command except the contents of the Sector Count register are ignored
and only one sector is read. The 512 data bytes and 4 ECC bytes are read into the buffer (with no ECC correction)
and then transferred to the host.
Command Issued by Host
Task File Register 7 6 5 4 3 2 1 0
COMMAND 22h (retries enabled) -or- 23h (retries disabled)
DRIVE/HEAD nu L nu D H[3:0] or LBA[27:24] of the sector/LBA to transfer
CYLINDER HI Cylinder[15:8] or LBA[23:16] of the sector/LBA to transfer
CYLINDER LOW Cylinder[7:0] or LBA[15:8] of the sector/LBA to transfer
SECTOR START Sector[7:0] or LBA[7:0] of the sector/LBA to transfer
SECTOR COUNT The number of sectors/logical blocks to transfer. This should be set to 01 for compatibility
FEATURES nu
Command Block specified upon completion/termination of Read Long command (22h/23h)
Task File Register 7 6 5 4 3 2 1 0
BSY DRDY DWF DSC DRQ CORR IDX ERR
STATUS 0 1 0 1 V V 0 V
DRIVE/HEAD na na na na H[3:0] or LBA[27:24] of the sector requested
CYLINDER HI Cylinder[15:8] or LBA[23:16] of the sector requested
CYLINDER LOW Cylinder[7:0] or LBA[15:8] of the sector requested
SECTOR Sector[7:0] or LBA[7:0] of the sector requested
SECTOR COUNT 00 if the command proceeded without error. 01 if an error occurred
BBK UNC MC IDNF MCR ABRT TK0NF AMNF
ERROR 0 0 0 V 0 0 0 0