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standby disk will automatically replace the failed drive and
the data will be rebuilt. The system administrator can
disconnect and remove the bad disk and replace it with a
new disk. The administrator can then make this new disk a
standby. The standby replacement table has a limit of 8
automatic replacements in any session (from power-on/
reset to the next power-off/reset). When the limit of 8 is
reached and a disk failure occurs, the standby replacement
will occur but will not be recorded in the replacement
table. To clear the "standby replacement" table, reboot the
system from a DOS bootable floppy, run the configuration
utility and select the option 'view/update configuration'
from the main menu. A red box labeled 'Drive Remap List'
will be displayed. Selecting the box will allow you to
continue. You should save the configuration without
making any changes, and exit the configuration utility. This
will clear the replacement table. You may now proceed to
boot your system and continue normal operations. In
normal use, the replacement table limit of 8 should not
cause any problems. Assuming that a disk fails about once
a year (drives we support generally come with a 5-year
warranty), the system would run continuously for a
minimum of 8 years before the table would need to be
cleared.
Storage Device
A collective term for disks, tape transports, and other
mechanisms capable of non-volatile data storage.
Stripe Order
The order in which SCSI disk drives appear within a drive
group. This order must be maintained, and is critical to the
controller's ability to "rebuild" failed drives.
Stripe Size
The size, in kilobytes (1024 bytes) of a single I/O
operation. A stripe of data (data residing in actual physical
disk sectors, which are logically ordered first to last) is
divided over all disks in the drive group.
Stripe Width
The number of striped SCSI drives within a drive group.
Striping
The storing of a sequential block of incoming data across
multiple SCSI drives in a group. For example, if there are 3
SCSI drives in a group, the data will be separated into
blocks and block 1 of the data will be stored on SCSI drive
© 2003, Adaptec, Inc.
1, block 2 on SCSI drive 2, block 3 on SCSI drive 3, block
4 on SCSI drive 1, block 5 on SCSI drive 2, and so on. This
storage method increases the disk system throughput by
ensuring a balanced load among all drives.
Sub-System Storage
A collection of disks providing data storage space to a
system user.
Sustained Data Transfer Rate
A rate of data transfer defined for continuous operation at a
maximum speed level.
Synchronous Data Transfer
Data transmission synchronized to a defined time interval,
and is faster than asynchronous SCSI because there is no
wait for acknowledgement of each byte from the receiving
device (up to 20MHz).
T
Target ID
The SCSI ID of a device attached to a controller. Each
SCSI channel can have up to 15 attached SCSI devices
(target ID from 0 to 6 and 8 to 15).
TCP/IP
Transmission Control Protocol/Internet Protocol, the basic
communication language or protocol of the Internet. It can
also be used as a communications protocol in intranets and
extranets. When set up with direct access to the Internet, a
computer is provided with a copy of the TCP/IP program
just as every other computer that you may send messages
to or get information from also has a copy of TCP/IP.
Throughput
The number of I/O requests satisfied per unit of time
(usually per second).
Transfer Rate
The rate at which data moves between the host computer
and storage, input, or output devices, usually expressed as
a number of characters per second.
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