NEC NEAX Express, Service & Reference Manual

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System Overview 1-11
Real-Time Clock/Calendar
The Y2K compliant real-time clock provides system clock/calendar information stored
in a non-volatile memory (NVRAM). The real-time clock battery provides power
backup for the real-time clock.
BIOS
A BIOS and Setup Utility are located in the Flash EPROM on the system board and
include support for system setup and PCI/ISA Plug-and-Play auto-configuration. A
number of security, reliability, and management features also have been incorporated to
meet vital server needs.
IDE Controller
IDE is a 16 bit interface for intelligent disk drives with disk controller electronics
onboard. The PCI/ISA/IDE Accelerator, also known as PIIX4e, is a multifunction
device on the server board that acts as a PCI based Fast IDE controller. The device
controls:
„
PIO and IDE DMA/bus master operations
„
Mode 4 timings
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Transfer rates up to 33 MB/s
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Buffering for PCI/IDE burst transfers
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Master/slave IDE mode
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Up to two devices per channel; two channels, IDE0 and IDE1
The IDE controller provides support for the internally mounted CD-ROM and an
optional tape device.
Network Controller
The system board includes a 10BASE-T/100BASE-TX network controller based on the
Intel 82559 single chip Fast Ethernet PCI Bus Controller. As a PCI bus master, the
controller can burst data at up to 132 MB/sec. The controller contains two receive and
transmit FIFO buffers that prevent data overruns or underruns while waiting for access
to the PCI bus. The controller has the following:
„
32-bit PCI bus master interface (direct drive of bus), compatible with PCI Bus
Specification, Revision 2.1
„
Chained memory structure with improved dynamic transmit chaining for
enhanced performance
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Programmable transmit threshold for improved bus utilization
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Early receive interrupt for concurrent processing of receive data
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On-chip counters for network management