[net.unix] SI shared disk system

jackson@nadc.ARPA (03/05/85)

    Has anyone out there had any experiences with a new Systems Industries
product call SIMACS or Systems Industries Multiple Access Controller system?
Their documentation claims of allowing up to 8 CPUS sharing up to 8 disks.
SI also claims support for Berkeley 4.2 and Bell System V Unix.

                                                       Thanks in advance,

                                                        jackson@nadc



SIMACS is a trademark of Systems Industries.
Unix is a trademark of the Bell System.

young@AMES-NAS.ARPA (Bruce Young) (03/05/85)

re: SIMACS


    SIMACS is supported for each os SV or 4.2, BUT you cannot
    share disks between two different os YET. Eventually, SI
    will attempt separate file directories with common storage.
    (End of speculation.)

    Ask about the SIMACS kernal modifications to provide locks
    on file accesses. The host accessing shared disks must 
    own the system disk during the access. This means all dirty
    buffers from the previous owner host must be flushed.
    thus, be certainto check benchmarks for interactive traffic;

    eg, any screen editor when run on multiple hosts.

    One merit, naturally, of SIMACS is access to the shared
    disks from another computer when your favorite host is
    down. However, ask SI about changing ownership of the
?
     Conclusion, SI persues essential system needs
     but check all benchmarks and kernal modifications.

-Bruce
 young@AMES-NAS.ARPA