Network Working Group D. Cantor
Request for Comments: 565 Computer Corporation of America
NIC: 18777 28 August 1973
 Storing Network Survey Data at the Datacomputer
 In November, 1972, Computer Corporation of America (CCA) and the
 Programming Technology Division of the Dynamics Modeling System (DMS)
 at M.I.T.'s Project MAC began planning to transmit to CCA's
 datacomputer [1] information about the behavior of ARPA network hosts
 collected by DMS's program SURVEY [2]. The information was to be
 stored at the datacomputer and retrieved by an interactive program
 that would address the datacomputer from DMS's PDP-10.
 One goal of this joint project was to enable DMS to retain all of the
 information that SURVEY collects: SURVEY had been running since late
 1971, saving only a short daily summary of its findings and
 discarding potentially useful details. A second goal was to discover
 and remove shortcomings in the interface between CCA's datacomputer
 and a program running at a remote host.
 The project was completed last month, and the programs described in
 this document have been operating successfully with the datacomputer
 since July 10.
 Part 1, below, describes SURVEY's output. Part 2 describes a program
 that retrieves portions of that output from the datacomputer.
Part 1: The Survey Database
 Every twenty minutes, DMS's program SURVEY wakes up and performs the
 initial connection protocol from the PDP-10 at DMS to the logger
 socket (socket 1) of each 28 network hosts.
 SURVEY records a date time, host, status,and response time for each
 host. A host may be in one of these states:
 undetermined or not surveyed
 disconnect from the network or dead
 network control program not responding
 ICP to logger aborted by the host
 ICP to logger timed out by SURVEY after 20 seconds
 logger available and responding within 20 seconds
 SURVEY records response times responding in tenths of seconds.
 When the data for all 28 hosts has been assembled, SURVEY transmits
 that data to CCA's datacomputer. If for some reason the datacomputer
 cannot accept the information, it is held at DMS and sent another
 time.
 The datacomputer's survey database is inverted by host, status,
 month, and year. That is to say that the datacomputer maintains
 several indices to records of one attempt to establish a full duplex
 connection to one host's logger: it maintains one such index for each
 host, one for each status, one for each month, and one for each year.
 The datacomputer can select records that are specified in boolean
 expressions by performing boolean operations on the inversion, and
 without consulting the data itself. The inversion thus facilitates
 rapid interaction between the survey retrieval program described
 below and the survey database at the datacomputer.
 SURVEY expresses the record of each attempt to access one host in 17
 ASCII characters. The record of one survey then occupies 17 * 28 =
 476 characters, and each day the datacomputer receives 3 * 24 * 476 =
 34,272 characters from DMS.
Part 2: Retrieving Survey Data
 A Program called SURRET, written at DMS in the language MUDDLE,
 allows one to selectively retrieve material from the survey data base
 stored at the datacomputer [3]. Its user may specify values, groups
 of values, or, where appropriate, upper and lower bounds for values
 of each of five fields: host name, date, time, response time, and
 host status. In addition, one may request that all five fields or
 any subset of the five be retrieved. A sample interaction with
 SURRET is reproduced below.
 <HOST (CASE-10)>$
 "OK"
 <DATE (AUG 5 73)>$
 "OK"
 <TIME (BETWEEN 2000 2400)>$
 "OK"
 <REQ ((TIME STATUS RESTIME))>$
 ;J205 10-08-73 1557:20 RHRUN: SUCCESSFUL COMPILATION
 .1241 10-08-73 1557:21 OCSOP: (DEFAULT) OUTPUT PORT OPENED
 TIME STATUS R.T.(1/10 SEC)
 2004 LOGGER RESPONDING (UP) 019
 2024 LOGGER RESPONDING (UP) 024
 2044 LOGGER RESPONDING (UP) 021
 2104 LOGGER RESPONDING (UP) 016
 2124 LOGGER RESPONDING (UP) 046
 2144 LOGGER RESPONDING (UP) 018
 2204 LOGGER RESPONDING (UP) 017
 2224 LOGGER RESPONDING (UP) 017
 2244 LOGGER RESPONDING (UP) 023
 2304 LOGGER RESPONDING (UP) 015
 2324 LOGGER RESPONDING (UP) 016
 2344 LOGGER RESPONDING (UP) 015
 "END OF DATCOMPUTER OUTPUT"
 The angle brackets, the material they enclose, and '$' (ESC or
 altmode) were typed by a person using SURRET. The remainder was
 typed by the system. The phrases in quotation marks are,
 effectively, SURRET prompts. The status messages beginning with ';'
 and '.' were generated by the datacomputer. The column headings and
 table were formatted by SURRET using figures retrieved from the
 datacomputer.
 SURRET generates datalanguage, sends it to the datacomputer, and
 processes systems diagnostics and data sent to it from the
 datacomputer. The datalanguage generated for the foregoing SURRET
 request was:
 FOR |SURVEY.LOGTRY, SURVEY.LOGTRY WITH
 ((YEAR EQ '73' AND MONTH EQ '08' AND DAY EQ '05')
 AND (HRMIN GE '2000' AND HRMIN LE '2400')
 AND (HOST EQ '013'))
 HRMIN=HRMIN ; STATUS=STATUS ; RESTIME=RESTIME ;
 END;
 The field names in the datalanguage were entered with file
 descriptors before the first data was loaded.
 One can ask SURRET to retrieve new data by changing the values of any
 number of fields and issuing a new REQ (request). The command
 <state> displays current values for the five prospective retrieval
 criteria. Thus:
 <HOST (USC-44)>$
 "OK"
 <STATE>$
 !HOST: (USC-44)STATUS: () RESTIME: () DATE: (AUG 5 73)
 TIME: (BETWEEN 2000 2400)!
 <REQ ((TIME STATUS RESTIME))>$
 ;J205 10-08-73 1610:08 RHRUN: SUCCESSFUL COMPILATION
 .1241 10-08-73 1610:09 OCSOP: (DEFAULT) OUTPUT PORT OPENED
 TIME STATUS R.T.(1/10 SEC)
 2004 LOGGER RESPONDING (UP) 020
 2024 LOGGER RESPONDING (UP) 008
 2044 LOGGER RESPONDING (UP) 008
 2104 LOGGER RESPONDING (UP) 009
 2124 LOGGER NOT RESPONDING (LNR) 000
 2144 LOGGER NOT AVAILABLE(DEAD) 000
 2204 NCP NOT RESPONDING (NNR) 000
 2224 LOGGER NOT RESPONDING (LNR) 000
 2244 LOGGER NOT AVAILABLE (DEAD) 000
 2304 LOGGER NOT AVAILABLE (DEAD 000
 2324 NCP NOT RESPONDING (NNR) 000
 2344 LOGGER RESPONDING (UP) 007
 "END OF DATCOMPUTER OUTPUT"
 We might have retrieved all of the foregoing output with:
 <HOST (CASE-10 OR USC-44)>
 Moreover,
 <HOST (CASE-10 CCA OR USC-44)>
 would cause SURRET to access the database twice, once for information
 about Case-10, and then a second time for information about the
 remaining two hosts.
 Detailed Survey data from July 10, 1973 forward is available either
 directly from the datacomputer or through SURRET. Persons who wish
 to use the datacomputer directly may obtain the pertinent documents
 through the NIC or by contacting Dale Stern at CCA (617-491-3670).
Endnotes
 [1] An overview of the data computer is given in Thomas Marill, The
 Datacomputer, 18 Oct '71, 7pp. (NIC 7979). A detailed study of the
 programming language for addressing the datacomputer is found in
 Computer Corporation of America, Datacomputer Project Working Paper
 No. 3, Datalanguage, 29 Oct '71, 78 pp. (NIC 8208). The current
 status of the language is reviewed in Richard Winter, Specifications
 for Datalanguage, Version 0/9, 6 Jun '73, 36 pp. (NIC 16446). A
 user's manual for version 0/9, will be released by CCA in September,
 1973.
 [2] SURVEY is described in Abhay Bhushan, A Report on the Survey
 Project, 22 June '73 (NIC 17375).
 [3] A detailed discussion of SURRET is found in Safwan Bengelloun,
 MUDDLE Survey Data Retrieval Programs, an internal DMS memo of 14
 June, '73. Our purpose here is to describe enough of the program's
 syntax and structure to show how it interacts with the datacomputer.
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