General SCSI questions

["David A. Moon" <Moon@STONY-BROOK.SCRC.SYMBOLICS.COM>]

    Date: Sat, 5 Aug 89 15:20 EET
    From: ROIMSE%METLA%ROUTER.FUNET.FI@Warbucks.AI.SRI.COM (Hannu
	  Saarenmaa)
    
    Everybody says that SCSI is the major standard for  
    peripherals in the 1990s, and hence a good investment.  

SCSI will certainly not be the only standard.  SCSI is somewhat limited
in performance so there are and will continue to be other standards at
the high end.  SCSI will probably continue to be a widely used standard
at the low end for some time.

    But how standard are the SCSI disk drives actually?
    I have heard that at least Seagate uses its own SCSI 
    controller in PCs.  

PCs (unlike Macs) don't come with SCSI capability built in,
so you have to add a SCSI controller from somewhere.

			If I want to buy an external drive 
    and use it now in my PC, can I later plug that into 
    a Sun with a SCSI interface?   Or into a Mac?

Generally the hardware is standard but you will need different
formatting and different software for each system, and in some cases a
different cable, you want to plug it into.  I would not count on being
able to move a SCSI drive from one system to another.  This may be
possible, especially for someone with experience, but if it's new to you
don't count on being able to do it.

    Can I have a SCSI interface for the 3620?
    In that case, what drive should I get, and can the SCSI 
    interface live with our existing drive controller in the 3620?

I'm not aware of any SCSI interfaces available for the 36xx line,
although there might be a product I'm unaware of.  I'm certain there is
no support for SCSI disks (for paging, LMFS, and Statice) on the 36xx
line.  The Ivory-based Symbolics systems all support SCSI, however
the XL400 does not support SCSI disks for paging, LMFS, and Statice
at present.