Distributed Name Service (DNS) Management Operations Manual

DNS Architecture
Introducing Distributed Name Service
31258 Tandem Computers Incorporated 1–9
DNS Architecture DNS consists of processes, configurations, and various files. Below is an overview of
the major elements of the DNS subsystem.
DNS Files Loaded by Install DNS is placed on your system by Install, as discussed in Section 3, “DNS Management
and Operations.” During the REPSUBSYS phase, Install loads the following files:
DNSCOM ($SYSTEM.SYSTEM.DNSCOM). Using DNSCOM commands, you can
create DNS databases, control the various DNS processes, and perform inquiries
and updates against DNS databases. These commands can be entered either
interactively from a terminal or from commands in disk files.
Some DNSCOM commands display the contents of the DNS database while other
commands cause a DNS database to be updated. Still other commands start and
stop DNS, open and close a name manager process, and display the status of DNS
processes.
Finally, some commands make DNSCOM easier to use by setting various defaults
for other commands to use, by reading commands from command files, by
displaying help information, and by handling other utility functions.
DNSMGR ($SYSTEM.SYSTEM.DNSMGR). DNSMGR is the executable object file
for the DNS name manager. A name manager is a management process through
which DNSCOM and user applications send Subsystem Programmatic Interface
(SPI) requests. All interaction between programs (including DNSCOM) and DNS
databases are performed by name managers. Each DNS database has its own
name manager process; hence, there may be multiple name managers running
simultaneously on a single system.
DNSEXP ($SYSTEM.SYSTEM.DNSEXP). DNSEXP is the executable code file for
the DNS name exporter. All replication of name definitions from one node to
another is handled by name exporter processes. Each replicated DNS database has
its own name exporter; consequently, there may be multiple name exporters
running simultaneously on a single system.
DNSHELP ($SYSTEM.SYSTEM.DNSHELP). DNSHELP is a data file used by
DNSCOM when responding to the HELP command and when constructing error
and warning messages.