Sun Microsystems Enterprise 250 Owner's Manual page 36

expandable up to 2 gigabytes. To enhance memory I/O performance, the system
transfers 64 bytes of data into or from memory on each memory transfer. For more
information about system memory, see "About Memory" on page 76.
System I/O is handled by two separate Peripheral Component Interconnect (PCI)
buses. These industry-standard buses support all main logic board I/O and up to
four PCI interface cards. One PCI bus operates at a 33-MHz clock rate and supports
up to three PCI cards, while the other bus can operate at either 33-MHz or 66-MHz
and supports one PCI card. All PCI cards plug into slots provided on the system's
main logic board. For more information about PCI buses, see "About Peripheral
Component Interconnect (PCI) Buses" on page 80.
Internal disk storage is provided by up to six hot-swappable 1-inch or 1.6-inch high,
3.5-inch wide, UltraSCSI disk drives. All six drives are supported by a 40-Mbyte per
second UltraSCSI interface provided directly on the system's main logic board. For
more information about disk storage, see "About Internal Disk Drives" on page 83.
External multi-disk storage subsystems and RAID storage arrays can be supported
by installing single-channel or multi-channel PCI host adapter cards along with the
appropriate system software. Software drivers supporting SCSI and other types of
devices are included in the Solaris operating environment.
An internal CD-ROM drive is standard on the Enterprise 250 server. The CD-ROM
drive has multimedia features, which include multi-session capability and fast access
for image and video data. An optional 1.44-Mbyte, 3.5-inch diskette drive is also
available.
A 5.25-inch half-height (1.6-inch) bay is provided at the front of the system, which
may be used to house a removable media SCSI device—such as an 8-mm tape drive,
a 4-mm DDS-2 or DDS-3 tape drive, or a quarter-inch cassette tape drive. For
additional details, see "About the SCSI Removable Media Bays and the External SCSI
Port" on page 95.
Up to four external tape devices can be attached to the standard 68-pin Fast/Wide
SCSI port provided on the system's rear panel. Additional external tape devices can
be supported with appropriate PCI host adapter cards.
The Enterprise 250 server can easily be connected to either a 10-Mbps or a 100-Mbps
Ethernet by means of an auto-sensing Ethernet interface provided on the system's
main logic board. Additional Ethernet interfaces or connections to other networks,
such as FDDI, ATM, or token ring, can be provided by installing the appropriate PCI
interface cards. For more information, see Chapter 10.
The system console device can be either a standard ASCII character terminal or a
local windowing subsystem. The ASCII terminal connects to the one of the system's
two serial ports, while a local graphics console requires installation of a PCI frame
buffer card, monitor, keyboard, and mouse. System administration can also be
performed from a remote workstation connected to the Ethernet.
The Enterprise 250 server provides two serial communications ports through a pair
of DB-25 connectors located on the rear panel. It also provides one external, 2-Mbyte
Sun Enterprise 250 Server Owner's Guide ♦ Revision A, June 1998
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