Alpha Microsystems AM-212-20 Руководство по установке - Страница 7
Просмотреть онлайн или скачать pdf Руководство по установке для Компьютерное оборудование Alpha Microsystems AM-212-20. Alpha Microsystems AM-212-20 18 страниц. Scsi 3-1/2” floppy diskette drive
Печатать страницуInstallation Instructions: AM-212-20 3-1/2" Floppy Diskette Drive
SCSI BUS TERMINATION
To function properly, the SCSI bus on your computer must be terminated at each end. The SCSI
controller on the system CPU board terminates one end of the bus; the opposite end of the bus can be
terminated in one of two ways: 1) using the preferred method—an external terminator, or 2) installing on-
board terminators in the peripheral that's at the other end of the SCSI cable. You should use method 2
only if, for some reason, you cannot use an external terminator.
External SCSI Bus Termination
The preferred way to terminate the SCSI bus in an AMOS computer is to install an external terminator.
Using an external terminator makes it easier to install an add-on subsystem (like a portable CD-ROM
drive), eliminating the need to remove terminators from a SCSI device inside the computer.
Several different external terminators are available from Alpha Micro:
Part Number
PRA-00222-00
PRA-00222-21
PRA-00222-20
The type of terminator you need depends on your computer and the SCSI peripherals in it. The AM-212-
20 is supported only on the AM-6000, AM-6060 and Eagle 450 computer systems, and therefore requires
an active terminator, either narrow or wide, depending upon the type of SCSI bus contained in your
computer system. This terminator is provided as a standard part of your computer system.
To use the external terminator, you need to insure that none of the SCSI devices inside the computer are
terminated. You also need to follow the guidelines in the section on providing termination power to the
SCSI bus, below.
TERMINATION POWER
To control SCSI bus termination properly, a termination power source must be provided; this is
especially important when using an external terminator.
Why is Termination Power so important when using an external terminator?
Any terminator must have a power source. Because an external terminator does not have its own source
of power, it must get its termination power from the SCSI bus. If termination power is not available on
the bus, the external terminator cannot do its job, which means your SCSI bus will not be terminated
properly. This may result in a computer that won't boot, or that "hangs" frequently.
All AMOS computers using the SCSI-2 or Wide SCSI-2 bus should be configured to supply termination
power via the host controller. When SCSI bus termination power is supplied by the host controller, no
SCSI peripheral should supply termination power to the bus.
SCSI subsystems attached to the main system should not have any additional devices supplying
termination power to the SCSI bus. Termination power should be supplied by the SCSI controller only!
PDI-00212-20-00, Rev. A01
Terminator Type
Narrow, passive
Narrow, active
Wide, active
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