The VIOC was first shipped in OpenVMS V6.0 and is a "cluster-wide,
write-through, file-oriented disk cache." Data is maintained across
file closure, and the replacement is least-recently-used, and cache
blocks are allocated on both read and write. VIOC can be enabled
and used on all OpenVMS configurations: single node or VMScluster.
Coherency is controlled by the lock manager. The VIOC is "below"
the available RMS caching, and RMS options can be used (in addition
to or in place of the VIOC) to designate specific local or global
caching resources for `hot' files, etc.
If you want details beyond this, you'll probably want to acquire the
OpenVMS source listings CD-ROMs. (There _may_ be VIOC technical
documentation publicly available -- if there is, I haven't seen it.)
To obtain most Digital parts, one calls 1-800-DIGITAL (based on your
Internet address, you appear to be in North America and can thus
access toll-free numbers), and order the source listings CD-ROM.
I do not know what (if any) prerequisites exist for the purchase of
As I believe the source listings CD-ROM uses the ODS-2 format only
(I don't believe this particular CD-ROM uses the ISO9660 format),
you may end up having to acquire access to an OpenVMS system in
order to mount and read the CD-ROM.