Technical data

Figure 2–2 Live Tracing on VMS Systems and Remote Servers
TRACE
utility
CTF
buffer
CTF$DCP
VMS
CTF Manager
DEC WANrouter
Trace records
Trace records
from local
tracepoints
VMS System
Remote Server
To screen
from remote server
2.3.1 CTF Support on VMS Systems
CTF support functions are provided on VMS systems partly by VMS and partly
by a process called CTF$DCP. VMS collects trace records from local tracepoints,
and CTF$DCP copies these trace records to a global section, which CTF uses as
an internal buffer.
In the case of live tracing (see Figure 2–2), trace records are read from the CTF
buffer as they arrive and are immediately formatted and displayed on your
terminal.
In the case of detached tracing (see Figure 2–3), the trace server process copies
trace records from the CTF buffer to a trace file. The contents of the trace file can
then be formatted and displayed later.
In the case of snapshot tracing, the CTF buffer is used as a circular buffer in
which trace records are collected until they are either written to a trace file or
displayed on your terminal in response to a CTF command.
Technical Overview 2–5