Technical information

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Glossary
host a processor, usually a CPU and memory, which communicates with devices over an interface
initiator device A component which originates a command
JBOD Just a Bunch Of Disks: a storage subsystem using multiple independent disk drives with or without
RAID configuration.
LUN Logical Unit Number: a SCSI or Fibre Channel identifier of a device
Maximum
Allowable
Volume Size
The Mac OS determines the maximum partition size. When using System 7.5.2 or later on a PCI-
based Macintosh
compatible computer, the maximum allowable volume size is 2 Terabytes. On a
NuBus based Macintosh, maximum allowable volume size is 4 Gigabytes. Any standard or RAID
volume may not be greater than the maximum allowable volume size. Refer to your operating system
user’s manual for more information.
originator an initiating device; a component which originates a command
partition a logically separate portion of a disk used to allow multiple systems to coexist on a single disk drive.
payload the part of the data field in a frame left after optional headers are removed
PCI Peripheral Component Interconnect: a bus which allows devices to communicate with the CPU.
RAID Originally Redundant Array of Inexpensive Disks, now Redundant Array of Independent Drives: a
storage system spanning multiple disk drives. The following standard RAID specifications will be used
here:
RAID 0: disk striping in which fixed-length sequences of data are mapped to member disks in a
regular rotating pattern.
RAID 1: Mirrored arrays: information written to one disk is also written to another simultaneously. Also
known as disk shadowing, real-time copy, and t1 copy.
RAID 10: Striped array with mirroring
receiver the ultimate destination of data transmission; a terminal device
SCSI Small Computer Systems Interface: a processor-independent standard for system-level interface
between a computer and intelligent devices including hard disks, floppy disks, CD-ROM, printers,
scanners, etc.
synchronous a way of sending data over a bus in which an initiator sending data does not wait for an
acknowledgement (ACK) that the data has been received before sending more data. See
asynchronous. Both the initiator and receiver must support synchronous mode.
target a device which responds to commands by an initiator
topology logical layout of the parts of a computer system or network and their interconnections
transfer rate the rate at which bytes or bits are transferred, as in megabytes or gigabits per second.
volume a usable quantity of storage composed of one or more partitions residing on one or more physical
drives. A standard volume creates a partition on a single drive.
Term Definition