Sleep Mode; Scsi Attachment; Physical Characteristics Of The Scsi Interface; Speed - IBM 39M5657 User Manual

Sleep Mode

To conserve energy when circuit functions are not needed for drive operation, the
drive features a power-management function that causes the drive's electronics to
enter a low-power mode known as sleep mode. To enter sleep mode, the drive must
be inactive for a minimum of 30 seconds (default value; this is programmable via
the mode pages); to exit, the drive must receive a command across the SCSI
interface, a command across the Library/Drive Interface (LDI or RS-422 interface),
or a load or unload request. When in sleep mode, the drive's response time to
commands that do not require media motion increases by up to ten microseconds.
Commands that require media motion may be delayed an additional 100
milliseconds because the tape must be retensioned.

SCSI Attachment

To communicate with a server, the drive uses the Ultra160 LVD SCSI interface.

Physical Characteristics of the SCSI Interface

The drive contains a high-density, 68-pin, D-shell receptacle connector (HD68) for
attachment to the server. The HD68 connector includes the connectors for the SCSI
signal, the SCSI ID, and the drive's power. The drive supports LVD SCSI cables
with HD68 connectors.

Speed

The Ultra160 LVD SCSI interface is compatible with older SCSI technology and is
capable of data transmission at 160 MB/s. Ultra160 SCSI uses the three
management features of the Ultra3 SCSI standard that specifically affect data
transfer rate:
v Double transition clocking - a data-transfer technique that enables data rates to
v Domain validation - a procedure that detects and adjusts SCSI configuration
v Cyclic redundancy check (CRC) - an error-checking technique
Because the cables, connectors, and terminators are the same for the Ultra160 and
Ultra2 SCSI interfaces, devices with those interfaces can be mixed on the same bus
and each device can operate at its fully rated speed.
4
IBM 400/800GB LTO3 Tape Drive User's Guide
double without increasing clock speed
issues that might prevent interoperation between SCSI devices