The Ten Commandments of SCSI
Copyright Gary Field, 2000
Originally published: May, 2000
Last updated: May, 2002
I. Thou shalt terminate both
ends (and ONLY the ends) of thine SCSI bus. If thine bus is WIDE, be sure
that both the lower half and upper half of the bus are properly terminated.
II. Thou shalt use active
(or LVD/SE) terminators wherever possible.
III. Thou shalt make certain
that each SCSI device has a SCSI ID unique unto itself.
IV. Thou shalt make certain
that terminator power is supplied by at least one device (laptop users
pay special heed!)
V. Thou shalt not make thine
SCSI bus longer than the speed of thy fastest device allows. These being:
VI. Thou shalt not mix the tribes
of SCSI! HVD cannot abide SE or LVD and neither can they abide HVD. Be
sure you know which tribe each of your devices is from. HVD is now considered
to be in exile and should be shunned if sighted in your vicinity.
6 meters for 5 MHz (SCSI-1 synch)
3 meters for 10 MHz (SCSI-2 Fast)
1.5 meters for 20 MHz (Fast-20/Ultra)
12 meters for 40 MHz (Fast-40/Ultra2) or higher using LVD.
VII. Thou shalt keep thine
device drivers up to date (But keep a known working version around too).
VIII. Thou shalt make certain
that the power supplies for your devices are adequate to supply their needs
(even during peak usage).
IX. Thou shalt not worship
false connectors. A special place in SCSI Hell is reserved for designers
using 25 pin connectors on SCSI devices!
X. Thou shalt double
check that thou hast obeyed all of the above before posting a question
to the enlightened in the comp.periphs.scsi newsgroup!
Following all of these religiously will deliver you from
SCSI Hell and into the promised land of fast, flexible multi-tasking.