SCSI Commands
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A Mode field of 0000b indicates that the data to be written will be preceded with a
four-byte header. This Write Buffer Data Header is reserved and must be set to all
zeros. The header will not be placed into buffer memory.
A Mode field of 0001b indicates that data to be written to the Medium Auxiliary
Memory will be sent.
A Mode field of 0010b indicates that only data to be written to the buffer will be sent.
A Mode field of 0100b or 0110b indicates download microcode.
A Mode field of 0101b or 0111b indicates download microcode and save.
The Buffer ID field indicates which buffer is to be written. All drives support buffer 0.
Other buffers may be available in the drive.
The Buffer Offset is used to specify the byte location within the specified buffer
where data is to be written.
The Parameter List Length field indicated the amount of data to be transferred. Care
needs to be taken so that the Buffer Offset plus the Parameter List Length does not
exceed the buffer capacity. If the buffer capacity is exceeded, no data is written and
Check Condition status is generated.
Soft Microcode Download
A soft microcode download will load the microcode image and reboot the drive
without flashing the image into memory.
Use Mode field of 0100b or 0110b to download the microcode image into memory
without saving (flashing). Buffer Offsets may be used in either of these Modes.
After the downloaded microcode image is in memory, it may be booted (without
flashing) by issuing a Write Buffer command with Mode 0100b or 0110b and a
Parameter List Length of zero. The downloaded code will then run on the drive until
the drive is power cycled. Upon power cycling the drive, the original firmware revision
will be restored.
Hard Microcode Download
A hard microcode download will load the microcode image, flash it into memory and
reboot the drive.
Use Mode field of 0100b or 0110b to download the microcode image into memory
without saving (flashing). Buffer Offsets may be used in either of these Modes.
After the downloaded microcode image is in memory, it may be flashed and booted
by issuing a Write Buffer command with Mode 0101b or 0111b and a Parameter List
Length of zero. The downloaded code will then run on the drive and remain in
memory until a subsequent hard microcode download is done.
