Internal Function; The Load Sequence; The Unload Sequence; Power-Fail Handling - Sony DDS-4 Product Description Manual

4. OPERATION

4. 3 INTERNAL FUNCTION

4. 3. 1 The Load Sequence

During load sequence, the following occurs:
1. The drive mechanism accepts the cassette, threads the tape and rewinds to Beginning-of-Media (BOM). The tape is
then moved to Beginning-of-Tape (BOT) and the Reference area is checked to find the tape format (DDS-4, DDS-
3, DDS-2, DDS and DDS-DC, blank, audio, and so on). If the format is not DDS-4, DDS-3, DDS-2, DDS and DDS-
DC, the drive rewinds the tape to BOT and awaits either a WRITE, Partitioning MODE SELECT or an
UNLOAD command.
2. The System area is then accessed and the System log read into the drive.
3. Finally the drive goes online.
In the case of two partition tape the drive detects that the tape has been formatted as a two partition tape when the
Reference Area is read. The drive will then automatically position to the beginning of partition 0 before coming on-line.
Partition 0 is the partition that begins the furthest from BOM.

4. 3. 2 The Unload Sequence

The drive will always write any buffered data out to tape followed by an EOD prior to initiating the Unload sequence.
During this sequence the tape is rewound to BOT and, if the tape is write-enabled, the copy of the tape log held in RAM
is written back to tape. The tape is then rewound to BOM and the tape unthreaded from the mechanism. At this stage the
tape is either retained in the drive or ejected, depending on media removal is enabled by the PREVENT ALLOW
MEDIA REMOVAL command.
In the case of two partition tape the drive detects that the tape has been formatted as a two partition tape when the
Reference Area is read during the load sequence. When the Unload operation begins the drive will then automatically
update the Tape Log for each partition before unloading the tape.

4. 3. 3 Power-Fail Handling

If there is a power-fail, the SDT-10000/SDT-11000 performs the following actions, and reverts to its default configura-
tion:
1. The drive remains positioned at the point where the power-fail or SCSI Reset occurred.
2. It executes the Power-Up sequence of self-tests. (When power is restored.)
3. If a tape is in the drive, the SDT-10000/SDT-11000 starts a load sequence.
The drive rewinds the tape to BOT and remains on-line.
4. The drive returns CHECK CONDITION status for the first command after the power-fail or Reset. The next
command from the initiator should be a REQUEST SENSE. The drive will return sense data including a sense key
that will indicate that the drive has been reset. (Sense Key / ASC / ASCQ = 06/29/00)

4. 3. 4 Diagnostic and Normal Status Displays

This chapter describes LED displays while the SDT-10000/SDT-11000 is starting up. When power is turned on, the
SDT-10000/SDT-11000 will go through its diagnostics to reach normal status. When a failure is detected during diag-
nostics, the LEDs show that the SDT-10000/SDT-11000 is out of order and needs to be repaired.

4. 3. 4. 1 Diagnostic Status Display

The SDT-10000/SDT-11000 starts with its Diagnostic function. This is made up of the Front Panel Test and the Kernel
Test.
4 - 4 SONY SDT-10000/SDT-11000 DDS Tape Drive