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SDLT 600 SCSI Interface Guide Chapter 3: SCSI Messages

81-81200-02 REV A01 January 2005 3-7

3.2.6 IGNORE WIDE RESIDUE (23h)

The SDLT tape drive sends the IGNORE WIDE RESIDUE message to the initiator to indicate that the

number of valid bytes sent during the last REQ/ACK handshake and REQB/ACKB handshake of a

DATA IN phase is less than the negotiated transfer width. The Ignore field indicates the number of

invalid data bytes transferred. The drive sends this message immediately following the DATA IN

phase and before any other messages. Figure 3-3 illustrates the data format of the IGNORE WIDE

RESIDUE message. Table 3-6 describes the field definitions.

Figure 3-3. IGNORE WIDE RESIDUE Message — Data Format

3.2.7 INITIATOR DETECTED ERROR (05h)

The initiator sends the INITIATOR DETECTED ERROR message to inform the SDLT tape drive that

an error has occurred that does not preclude the drive from retrying the operation (for example, a bus

parity error). The source of the error may either be related to previous activities on the SCSI bus or

may be strictly drive-related. When the drive receives this message, it may attempt to re-transfer the

last command, data, or status bytes using the RESTORE POINTERS message mechanism.

The drive’s response to and its handling of an INITIATOR DETECTED ERROR message are based on

when, in the I/O process, the initiator sends the message. Table 3-7 summarizes the drive’s response.

Bit

Byte

7 6 5 4 3 2 1 0

0 Message Code (23h)

1 Ignore (01h)

Table 3-6. IGNORE WIDE RESIDUE Message — Field Definitions

Ignore Invalid Data Bits (16-bit Transfers)

00h Reserved

01h DB(15 - 8)

02h - FFh Reserved

1 2 ... 30 31 32 33 34 35 36 37 38 39 40 ... 293 294

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Quantum 1200 Series DAT Autochanger Guía de usuario Pagina 35