It is a multi-device interface, It is a fast parallel interface – Nikon LS-10 Installation Guide for Macintosh User Manual
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Chapter 3
The SCSI Interface
2. It is a multi-device interface.
As noted throughout this chapter, the SCSI interface can support up to seven
independent SCSI devices, one of which is your Macintosh.
Advantages: • Ability to daisy chain multiple devices off of one interface to the
computer. • Allows easy system expandability.
Limitations: • Not all SCSI devices can work together on the same SCSI bus. •
Some SCSI devices will not operate correctly if daisy chained in a particular order. This
may require that you experiment with the order of the devices in the daisy chain. •
Some SCSI devices are internally-terminated at the factory. This may require that you
or a qualified technician remove this termination if the device is to be placed in the mid
dle of a SCSI chain. • When daisy chaining many SCSI devices together, the total
length of all the SCSI cables used in the chain should not exceed 18 feet. A chain of
more than 18 feet may result in lost data and ‘lost’ devices. • System performance can
suffer as devices are added to the SCSI bus. This is related to the length of the SCSI
chain. Data has a longer path to travel as more devices and cables are added to the SCSI
chain, resulting in electrical instability and signal reflections. This leads to miscommu-
nicated bytes, which must be re-sent until they are received correctly, a lengthy proce
dure.
3. It is a fast parallel interface.
Advantages: • The complex SCSI ‘handshaking’ is managed in hardware, allow
ing high speed variable size block transfers. In other words, the SCSI interface allows
fast transfer of blocks of data.
Limitations: • The parallel bus limits the length of the SCSI chain, and therefore
the distance between SCSI devices.
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4. SCSI devices can easily be connected, disconnected, and moved.
Advantages: • Allows portability of devices between different computers. •
Allows easy relocation of devices. • Allows easy system expandability.
Disadvantages: • Connecting and disconnecting SCSI devices that reside on the
same SCSI bus as the computer’s bootable disk can cause loss of data and/or damage to
the SCSI devices if performed while the computer or any SCSI device is powered on.
Never connect or disconnect SCSI devices while the computer or any SCSI device
is powered on.
Nikon
Coolscan Installation Guide for Macintosh
Page 31