🚀 go-pugleaf

In article <8395@cg-atla.UUCP>, weber@cg-atla.UUCP (Jeff Weber) writes:
> In article <11052@stag.math.lsa.umich.edu> derrick@cs.AthabascaU.CA (Derrick Rowlandson) writes:
> >Original-posting-by: derrick@cs.AthabascaU.CA (Derrick Rowlandson)
> >Original-subject: SCSI cabling
> >Reposted-by: emv@math.lsa.umich.edu (Edward Vielmetti)
> >
> >After spending a couple hours trying to cable up some SCSI peripherals
> >to a SUN i would like to pose the following questions.
> >
> >A SCSI bus consists of a 50 pin bus running from a SCSI controller.
> >Bus length can be up to 15 feet.
> 	UPTO 20 feet and that includes the bus lenght used *inside* the 
> 	enclosure of choice.

    Actually, 6 meters or just over 19.5 feet is the specified maximum length
    for SINGLE-ENDED SCSI.

> >Where must a SCSI bus be terminated? Only once, and at the last device on 
> >the bus would seem to be the logical choise.
> 	Yes.  It is the last physical device not the highest id's device.

    The SCSI bus must be terminated on BOTH ends.  In a typical configuration
    this would be done at the host (usually at one end of the bus) and at the
    last physical device on the bus as mentioned above.  If, however, the host
    is somewhere in the middle of the bus (not an illegal configuration) the
    bus must be terminated at the devices on each physical end of the bus.

> >When taping into a SCSI bus, the tap or stub lenght can only be a few
> >inches in lenght i guess?
>            (LENGTH) This stub can only be 5inches long.

    I believe the maximum stub length is 4 inches but I don't have my SCSI
    spec handy to verify this.

> >But can you get away with a longer stub lenght (LENGTH)
> >if you also terminate that specific device?
> 	No.

    Agreed.  You are asking for strange and potentially data destructive
    problems if you do this.



    Guy McConnell
    Intergraph Corp.
    Mass Storage Peripheral Evaluation