Instruction manual

SECTION 8. FILES, PROTOCOLS, AND UTILITIES
8-7
Decimal = "DECIMAL(" Digit [ Digit ] "," Digit [ Digit ] ")".
VarChar = "VARCHAR(" Digit { Digit } ")".
FieldValue = ( TimeStamp | RecordNumber | Number | String ).
TimeStamp = "'" Year "-" Month "-" Day " " Hour ":" Minute ":" Second "'".
Year = 4( Digit ).
Month = 2( Digit ).
Day = 2( Digit ).
Hour = 2( Digit ).
Minute = 2( Digit ).
Second = 2( Digit ) [ "." { Digit } ].
RecordNumber = 10{ Digit }.
Number = { Digit } [ "." ] { Digit }.
String = "'" { Character } "'".
A typical data record might look something like this:
Lgr,Sec15 (TMSTAMP TIMESTAMP,RECNBR DECIMAL(10,0),Battery_V FLOAT,Temp FLOAT)
VALUES ('1993-12-08 15:02:00',123456,13.5,72.123)
only without the tabs and carriage return in the middle. One with strings might look like this.
PC1,StatMsg (TMSTAMP TIMESTAMP,RECNBR DECIMAL(10,0),SrcStn VARCHAR(256),AbtStn
VARCHAR(256),Hop DECIMAL(3,0),MessageVARCHAR(256)) VALUES ('1993-12-08
15:02:02.25',13355,'PC1',0,'DBSelect End Pipe Queue Dump')
The acknowledgment records to be sent back to the server for the two records shown above would be:
Lgr,Sec15,123456
and
PC1,StatMsg,13355
8.5.1 IMPLEMENTATION
With RTMS, a Named Pipe version of the
server is implemented in the DBSelect
program. DBSelect is used to select tables that
are made available via the Named Pipe and to
ensure that all collectable records are
transferred to the client.
The name of the Named Pipe provided by
DBSelect is "\PIPE\RTMS". With an
appropriate network operating system this pipe
can be accessed over the network.
DBSelect also provides an unacknowledged
version of LDEP on a pipe named
"\PIPE\RTMA". On this pipe the server sends
data records in the exact same format as
specified by LDEP, but the server does not wait
for acknowledgment records to come back. It
is a simple one way unacknowledged flow that
can be used by programs like "copy".
The TCPS program, when used with DBSelect,
is used to provide the TCP/IP Sockets version
of LDEP. TCPS reads records from the Named
Pipe and writes them to a TCP/IP Socket.
TCPC is an example program used to show
how a user-written client would connect to the
TCPS server.
8.5.2 REFERENCES
1
Booch, Grady 1994. Object-Oriented Analysis
and Design, Second Edition. The Benjamin/
Cummings Publishing Co., Inc.
2
Harel, D. 1987. Statecharts: A Visual
Formalism for Complex Systems. Science of
Computer Programming vol. 8.
3
Wirth, Niclaus 1983. Programming in Modula-
2, Second, Corrected Edition. Springer-Verlag.
Part 1.3 (A notation to describe syntax).
8.6 SAMPLE ASCII FILE CREATED BY
DBSELECT
The following describes the header found in this
ASCII file created by DBSelect: