Sun Microsystems StorageTek 96257 - Manual (Page 88)

C-88 Sun Confidential: Internal Only 96257
Revision A
control unit address. The base channel address to
which a control unit can respond.
conversion. A process that changes the basic capability
of a unit in a system and may be a disruptive, requiring a
customer to turn over use of the unit to a CSE. Conver-
sions may require special tools and higher-level skills of
a technical specialist. Contrast with upgrade.
count-key data (CKD). A recording format that writes
variable-length records. Contrast with fixed-block archi-
tecture.
CPAT. Corporate Product Acceptance Testing.
CPD. Central parts depot.
CPD. See controlled power-down.
CRC. See Customer Resource Center.
CRU. Customer-replaceable unit. Any item, module, or
unit on a system that a customer can replace without as-
sistance from a CSE.
CSA. Canadian Standards Association. A group serving
industry, government, and consumers which develops
product testing and certification standards and codes.
The Canadian counterpart of Underwriters Laboratories.
CSE. See Customer Service Engineer.
CSL. Cartridge scratch loader; cartridge stacker/loader.
CSL. See Customer Services Logistics.
CSM. See Configuration Status Monitor.
CSR. Control Status Register.
CSRC. A Sun StorageTek internal tool managed by the
NPDC that allows remote connection, operator panel ac-
cess, and remote file download capability for virtual disk
systems including VTSS.
CTR. Cache track recovery.
CTS. Corporate Technical Standard(s).
Customer Resource Center (CRC). A Sun StorageTek
website (
www.support.stortek.com ) that provides re-
sources including product documentation, tools and ser-
vices, and customer training information.
Customer Service Engineer (CSE). A technical engi-
neer who interacts with the end-user customers and is
responsible for fixing product problems and maintaining
product performance in customer accounts.
Customer Service Manager (CSM). A member of the
Sun StorageTek management team with first-line techni-
cal management responsibility for addressing problems
in customer accounts.
Customer Services Logistics (CSL). An organization
within Sun StorageTek responsible for coordinating deliv-
ery of spare parts to field depots worldwide.
cyclic redundancy check (CRC). A check performed
on data to see if an error has occurred in the transmit-
ting, reading, or writing of data.
D
DAC. See disk array controller.
DACD. Disk array controller display. FRU designation for
a VTSS local operator panel.
DASD. Direct-access storage device. (1) A storage de-
vice (typically a magnetic disk) in which data access
times are effectively independent of the location of the
data on the device. Conversely, in a serial-access stor-
age device (e.g., a magnetic tape), data must be access-
ed serially, such that data at the end of the tape spool
take much longer to access than data on the tape which
is passing immediately over the read/write head. (2) A
device in which the media is always available to the
read/write head without requiring mounting by an exter-
nal agent.
data compression. See compression.
data striping. The process of writing large blocks of data
across multiple drives and array groups to enhance data
protection capabilities.
data transfer rate. The speed at which data can be
transferred. Measured in bits per second (bps) for a mo-
dem, and in megabytes per second (MBps) for a hard
drive or fiber channel.
database. A collection of data arranged for ease and
speed of retrieval.
dB. Decibel.
DBU. Disk buffer utilization. The ratio of used to total
VTSS buffer capacity.
DC. Direct current. An electric current flowing in one di-
rection only. Contrast with alternating current.
DCN. Document Change Notice.
DDR. Defect discovery rate.
DDR. Dynamic device reconfiguration.
DDSR. Deleted Data Space Release. A VTSS ExPR
software function that informs a controller when function-
al volume datasets or minidisks are deleted, so that
physical disk space occupied by deleted data can imme-
diately become free space, thereby reducing DBU.
decibel (dB). In data transmission terms, a unit that
measures the ratio of the difference in power between
two electric signals.
decompress. To restore a compressed file to its original
size.
dedicated connection. In an ESCD, a connection be-
tween two ports that is not affected by information in link
frames. A dedicated connection restricts the ports from
communicating with other ports, and appears as one
continuous link.
deinstallation. Physically disconnecting a subsystem
with the intent of removing it from a customer site. Con-
trast with relocation.
destage. In VSM, the non-synchronous write of new or
updated data from cache or nonvolatile storage (NVS) to
the VTSS disk arrays.
Detailed Manufacturing Instruction. A document con-
taining a step-by-step description of the correct way to
assemble an item, including illustrations if necessary.
device. A single physical HDA.
device reconstruction. A VTSS automatic background
function that recreates and rewrites data from a failed
device to a spare device using the functional track recov-
ery (FTR) facility.
DFE. Distributed Fabric Element.
DFT. Direct field transfer.
Diagnostic Manager (DMGR). In VTSS, a facility that
administers, controls, and coordinates all diagnostic ac-
tivity within the VTSS environment through the diagnos-
tic submonitors (DSMs).