Network Working Group E. Faeh
Request for Comments: 437 Computer Systems Laboratory, UCSB
NIC: 13701 30 June 1973
DATA RECONFIGURATION SERVICE AT UCSB
This purpose of this RFC is to announce the availability of the Data
Reconfiguration Service (DRS) at UCSB, and to describe the use of the
DRS Time Sharing System. The DRS is an experiment in a flexible
means for reformatting Network data streams. The DRS provides a
means for coupling processes with different input/output interfaces,
and carrying out user specified transformations on the data passing
between them. Samples of representative uses of the DRS include
field insertion, field deletion, variable length string processing,
string length computation, field transposition, character packing and
unpacking, and character set translations.
To use the DRS, a user first defines a "form", or a description of
the reformatting to be performed on data passing between two sockets
(a form is associated with each unidirectional message path). DRS
may then be directed to establish Network connections with the two
processes involved and to monitor the dialogue between them. DRS
receives an input stream from one process, reformats the input
according to the rules specified by the form, and emits the
reformatted data as an output stream to the second process. The two
processes communicate as if they were directly connected to each
other.
Three major components comprise the DRS: a compiler which reduces DRS
source programs (forms) to a simpler, machine independent instruction
sequence (object program), an interpreter which executes the object
program created by the compiler, and an executive program, the DRS
Time Sharing System, which interfaces the Network user to the DRS.
Detailed descriptions of the DRS source language and compiler are
available in the following documents:
"The Data Reconfiguration Service--An Experiment in Adaptable,
Process/Process Communications", The Rand Corp., R-860-ARPA,
November 1971.
"Data Reconfiguration Service Compiler: Communications Among
Heterogeneous Computer Centers Using Remote Resource Sharing", The
Rand Corp.,R-887-ARPA, April 1972.
The DRS Time Sharing System (DRS/TSS) and its server Telnet are
currently available and addressable through socket 1281 decimal.
DRS/TSS interfaces the user to the DRS. In addition to a subset of
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RFC 437 DATA RECONFIGURATION SERVICE AT UCSB June 1973
'TENEX-like' executive commands, commands are available for creating
and storing forms by name, and for invoking the DRS compiler or
interpreter. Since both the compiler and the interpreter run
asynchronously to the DRS/TSS, the user is notified when execution of
his requests for compilations or interpreting are initiated and
terminated. In addition, a diagnostic message is supplied by the
interpreter whenever it terminates execution of a form.
When a user connects to DRS/TSS he is allocated an internal TTY
number by which his terminal is identified. When the user issues a
command to invoke the compiler or interpreter, his TTY number and a
user specified job name are used to uniquely identify the request.
The jobname is thereafter used to refer to the request. A Network
host is specified by host name, or by host number preceded by #. A
socket number is specified as an integer, optionally preceded by a
(decimal) to indicate the radix used. Decimal is the default radix
and positive the default sign. A negative socket number is
maintained in two's complement form.
The following control characters are recognized by DRS. Control A
(SOH) or rubout (DEL) delete the last character, control V (SYN)
deletes the last word, control W (ETB) deletes the last phrase, and
control X (CAN) deletes the entire line. Control D (EOT) displays
the current word, control E (ENQ) displays the current phrase, and
control F (ACK) displays the entire line. Control Y (EM) displays
the name of the current phrase. Command accept is carriage return-
line feed, or period. A space will force recognition of the current
word, and '?' will list the input(s) currently possible.
The following sections describe the DRS/TSS command syntax.
denotes command accept, and brackets [] denote optional information.
All literal information is enclosed in quotes ''. Choose one
alternative form items in parenthesized lists separated by |.
DRS/TSS COMMAND SYNTAX
Commands:
'ATTACH'
'BREAK' (|)
'COMPILE'
'CONVERT' ['TO']
'DEFINE'
'DELETE' []
'DETACH'
'DIRECTORY'
'DISCONNECT'
'FULLDUPLEX'
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RFC 437 DATA RECONFIGURATION SERVICE AT UCSB June 1973
'HALFDUPLEX'
'HELP'
'LINE_AT_A_TIME'
'LINK' ('ENABLE'|'DISABLE'||)
'LIST' []
'LOGIN'
'LOGOUT'
'MONITOR' (|)
'QUIT' (|)
'RADIX'
'RENAME' ['TO']
'RESPONSE' ('ALL'|HANDHOLD'|'PROMPT'|'NORMAL'|'UNUSUAL'|
'ERRORS'|'NONE')
'RUN' ('SIMPLEX' |
'DUPLEX' '('
')' )
'SELECT' (|)
';'
Substitutions:
= ['<' ',' '>']
RFC, FYI, BCP