Download Chapter 4 - Connectors

Serial Port: A physical connection with a computer for the purpose of serial data exchange with a peripheral device.
The port requires an I/O address, a dedicated IRQ line, and a name to identify the physical connection and
establish serial communication between the computer and a connected hardware device. A serial port is often
referred to as a COM port.
Shadow Memory: RAM in the address range 0xC000h through 0xFFFFFh used for shadowing. Shadowing is the process of copying BIOS extensions from ROM into DRAM for the purpose of faster CPU access to the extensions when the system requires frequent BIOS calls. Typically, system and video BIOS extensions are
shadowed in DRAM to increase system performance.
Single In-Line Memory Module (SIMM): A small, rectangular circuit board on which is mounted semiconductor
memory ICs.
Standoff: A mechanical device, typically constructed of an electrically non-conductive material, used to fasten a circuit board to the bottom, top, or side of a protective enclosure.
Static Random Access Memory (SRAM): A semiconductor RAM device in which the data will remain permanently
stored as long as power is applied, without the need for periodically rewriting the data into memory.
Symmetrically Addressable SIMM: A SIMM, the memory content of which is configured as two independent banks.
Each 16-bit wide bank contains an equal number of rows and columns and is independently addressable by
the CPU via twin row address strobe registers in the DRAM controller.
Synchronous Expansion Bus (SEB): An extension of the local bus on some systems that is provided for the purpose
of convenient interface with a user-designed peripheral board. The SEB operates at the speed of the CPU and
provides an ISA-like interface to the SVGA, PCM ATA, keyboard/mouse, and IDE controllers.
System Memory: See Conventional Memory.
U
User Editable Drive (UED): A feature of the Baby-AT baseboard’s BIOS. When a “User” type hard disk drive setting
shows in the IDE Adapter Sub-Menu the BIOS queries the hard disk drive for the purpose of retrieving disk
geometry. If the hard disk drive is capable of providing this information, the BIOS uses it to automatically set
up the drive for use with the system.
V
Video Graphics Adapter (VGA): A popular PC graphics controller and display adapter standard developed by IBM.
The standard specifies, among other things, the resolution capabilities of the display device. Display devices
meeting the VGA standard must be capable of displaying a resolution of 640 horizontal pixels by 480 vertical
pixels with 16 screen colors.
W
Wait State: A period of one or more microprocessor clock pulses during which the CPU suspends processing while
waiting for data to be transferred to or from the system data or address buses.
X-Y-Z
Xmodem: A popular serial communication protocol which specifies, among other things, the size of data packets to
be transmitted or received, and error correction methodology.
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