TYAN TOMCAT I7221 User Manual page 103

Tomcat i7221 S5150 Appendix I: Glossary
RAID (Redundant Array of Independent Disks): a way for the same data to be stored in
different places on many hard drives. By using this method, the data is stored redundantly,
also the multiple hard drives will appear as a single drive to the operating system. RAID level 0
is known as striping, where data is striped (or overlapped) across multiple hard drives, but
offers no fault-tolerance. RAID level 1 is known as mirroring, which stores the data within at
least two hard drives, but does not stripe. RAID level 1 also allows for faster access time and
fault-tolerance, since either hard drive can be read at the same time. RAID level 0+1 is both
striping and mirroring, providing fault-tolerance, striping, and faster access all at the same
time.
RAIDIOS: stands for RAID I/O Steering, a type of RAID technology from Intel. RAIDIOS is a
specification used to enable an embedded I/O controller, embedded on the motherboard, to be
used as just an I/O controller or to be the I/O component of a hardware RAID subsystem. The
RAIDIOS circuit allows an I/O Processor (either embedded on the motherboard or on an add-
in card) to configure the I/O controller and service the I/O controller's interrupts. The I/O
controller and the I/O Processor together are two of the primary components of a hardware
RAID subsystem.
RAM (Random Access Memory): technically refers to a type of memory where any byte can
be accessed without touching the adjacent data, is often used to refer to the system's main
memory. This memory is available to any program running on the computer.
ROM (Read-Only Memory): a storage chip which contains the BIOS; the basic instructions
required to boot the computer and start up the operating system.
SATA (Serial ATA): is an evolutionary replacement for the Parallel ATA physical storage
interface. Serial ATA is a drop-in solution in that it is compatible with today 's software and
operating systems. It will provide for systems which are easier to design, with cables that are
simpler to route and install, smaller cable connectors, and lower voltage requirements.
SDRAM (Synchronous Dynamic RAM): called as such because it can keep two sets of
memory addresses open simultaneously. By transferring data alternately from one set of
addresses and then the other, SDRAM cuts down on the delays associated with non-
synchronous RAM, which must close one address bank before opening the next.
Serial port: called as such because it transmits the eight bits of a byte of data along one wire,
and receives data on another single wire (that is, the data is transmitted in serial form, one bit
after another).
SCSI Interrupt Steering Logic (SISL): Architecture that allows a RAID controller, such as
AcceleRAID 150, 200 or 250, to implement RAID on a system board-embedded SCSI bus or a
set of SCSI busses. SISL: SCSI Interrupt Steering Logic ( LSI ) (only on LSI SCSI boards)
SIMM (Single In-line Memory Module): formally the most common form of RAM for
motherboards. They must be installed in pairs, and do not have the carrying capacity or the
speed of DIMM modules.
Sleep/Suspend mode: in this mode, all devices except the CPU shut down.
SRAM (Static RAM): unlike DRAM, this type of RAM does not need to be refreshed in order
to prevent data loss. Thus, it is faster and more expensive.
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