Appendix A Glossary - ATTO Technology ExpressSAS H1208 HBA Installation And Operation Manual

Some terms used in the SAS/SATA industry are defined below. More information is available through the ATTO Technology website
(atto.com), or the Storage Area Networking Industry Association (www.snia.org).
Term Definition
ANSI American National Standards Institute
Auto Negotiation Hardware senses and automatically responds depending on configuration
Bit Smallest unit of data a computer can process: a single binary digit with a value of either 0 or 1
Bus
A collection of unbroken signal lines used to transmit information from one part of a computer system to
another; taps on the lines connect devices to the bus
Byte An ordered set of 8 bits
CPU Central Processing Unit: the portion of the computer that actually performs computations
Device Driver A program that allows a microprocessor to direct the operation of a peripheral device
DMA Direct Memory Access: a way to move data from a storage device directly to RAM without using the CPU's
resources
DMA bus master Allows a peripheral to control the flow of data to and from system memory by block as opposed to allowing
the processor to control the data by bytes (PIO or programmed I/O)
Host A processor, usually a CPU and memory, which communicates with devices over an interface
I2C (Inter-Integrated Circuit) is a multi-master serial single-ended computer bus that is used to attach low-speed
peripherals to a motherboard, backplane or embedded system
I2C Header I2C header is a connector on the adapter used to connect an I2C cable
LED Light-emitting diode: a type of diode that emits light when current passes through it; visible LEDs are used as
indicator lights on all sorts of electronic devices
Parity Checking A method which verifies the accuracy of data transmitted over the SCSI bus by adding one bit in the transfer
to make the sum of all the bits either odd or even (for odd or even parity); an error message occurs if the
sum is not correct
PCI Peripheral Component Interconnect. Allows peripherals to be connected directly to computer memory,
bypassing the slower ISA and EISA busses

Appendix A Glossary