[alt.sys.sun] Sun <--> Sun via SCSI?

km@mathcs.emory.edu (Ken Mandelberg) (05/16/91)

Would it be feasible to connect to adjacent workstations (Suns in this
case) using scsi? Would you expect to be able to get better than ethernet
throuhput on bulk transfers.  There would be no peripherals competing on
this connection.

-- 
Ken Mandelberg      | km@mathcs.emory.edu          PREFERRED
Emory University    | {rutgers,gatech}!emory!km    UUCP 
Dept of Math and CS | km@emory.bitnet              NON-DOMAIN BITNET  
Atlanta, GA 30322   | Phone: Voice (404) 727-7963, FAX 727-5611

dlt@wacker (Don Turrell) (05/19/91)

km@mathcs.emory.edu (Ken Mandelberg) writes:

> Would it be feasible to connect to adjacent workstations (Suns in this
> case) using scsi? Would you expect to be able to get better than ethernet
> throuhput on bulk transfers.  There would be no peripherals competing on
> this connection.
> 
> -- 
> Ken Mandelberg      | km@mathcs.emory.edu          PREFERRED
> Emory University    | {rutgers,gatech}!emory!km    UUCP 
> Dept of Math and CS | km@emory.bitnet              NON-DOMAIN BITNET  
> Atlanta, GA 30322   | Phone: Voice (404) 727-7963, FAX 727-5611

THe SCSI protocol has provisions for allowing the bus to be used
for system to system communication. My company Performace Technologies
has carved out a nitch in supplying SCSI Host adapters on the VMEbus
that can be run back to back for system communication. The SCSIbus
rates are 3-5 Mbytes/sec (24-40 Mbits/sec) vs ethernet (10 Mbits/sec
at its best). So SCSI can be used for an effect system to system link
with good performance capability. 

That's the good news..... The bad news is you just can't connect
two SCSI adapters together and have them communicate. For instance
our SCSI Host Adapter on VME has substantial firmware onboard (it is
an intelligent adapter) to handle packetizing of the data when it
is communicating with an other Host Adapter (vs a disk or tape drive
on the SCSIbus). The software driver (ie in the SUN) must also be 
able to support this type of operation (the standard SUN driver does
not do this).

So in principle using SCSI for system to system communication provides
a great high speed standard link (even for going dissimilar system
to dissimilar system). However the standard SUN implementation (hardware
and software) is not set up to support this use of the SCSIbus.

Have I scared you off???...if not contact me by e-mail (dlt@pt.com)
and I can give you somemore details on this subject.

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