Write Buffer
96122 • Revision: F Chapter 6 SCSI Commands 233
Write Buffer Command Descriptions:
Mode This field indicates the type of download to be performed. The library
supports two modes:
110b = Download Microcode with Offsets
■ This mode is used for multiple transfer downloads.
■ The first Write Buffer command must contain data for the start of the image
■ The remaining commands must send data in order.
■ The library does not check for data overlap. It is up to the initiator to keep
track of the amount of microcode transferred and the microcode placement.
■ This mode cannot be used exclusively to download microcode. It is used for
all Write Buffer commands in a download except for the last one.
111b = Download Microcode with Offsets and Save
■ This is the last Write Buffer command to tell the library that the download is
finished.
■ A change to this mode from any other mode is considered a new download
request, and terminates any active download.
Buffer ID This field defines the region of memory to be modified.
Currently only a value of 00h is supported.
A non-zero value returns a Check Condition status with an Illegal Request
sense key.
The additional sense code is set to Invalid Field in CDB that identifies Byte 2.
Buffer Offset This field identifies the offset from the start address of the load area into which
the data is placed.
For modes 100b and 101b, this field is set to 0.
A non-zero results in a Check Condition status with an Illegal Request Sense
Key. The additional sense code set to Invalid Field in CDB that identifies Byte 3
(the parameter list length).
For modes 110b and 111b, this field is ignored.
Parameter List Length This field indicates the number of bytes being sent to the library.
A length of 0 is allowed for mode 111b only.
Blocks are limited to a maximum of 16,384 bytes.
The length value must be an even number; an odd number results in a Check
Condition with an Illegal Request sense key.
The ASC will be set the Invalid Field in CDB identifying Byte 6.
Any other error also results in a Check Condition status with an Illegal Request
sense key. The ASC will be set to Invalid Field in CDB identifying Byte6.
Clear Partial Images This field is used to clear any partial images currently stored as a result of
prior Write Buffer commands using the Download Microcode With Offsets
mode.
The value is set to 01b and the mode is set to Download Microcode With
Offsets.
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