The Datacomputer was an
ARPANET-connected
database system supported by the
Computer Corporation of America in
Cambridge, Massachusetts. It was intended as a
computing utility
Utility computing or The Computer Utility is a service provisioning model in which a service provider makes computing resources and infrastructure management available to the customer as needed, and charges them for specific usage rather than a ...
sharing resources among multiple
ARPA projects, in particular in
seismology and
climatology. It operated from August 1973
["Arpanet DBMS Uses Decsystem-10, Mass Memory", Computerworld, May 9th 1977] until 1980.
It was hosted on a
DEC PDP-10 running the
TENEX operating system (ARPANET host CCA-TENEX, address 31)
[Elizabeth J. Feinler, ed., Arpanet Resources Handbook, October 1978, NTIS AD-A065 421]
p. 161-162
/ref> and was designed to support 3 trillion bits of storage (375 GB). Besides storage, the Datacomputer also offered data conversion utilities which supported the multiple data formats used at the time.[ Janet Abbate, ''Inventing the Internet'', p. 98-99, 103-104]
The largest user of the Datacomputer was ARPA's Seismic Data Analysis Center (SDAC) ( Alexandria, Virginia), which monitored underground nuclear tests.[Richard Winter, Jeffrey Hill, Warren Greiff, "Further Datalanguage Design Concepts", Network Working Group ]RFC
RFC may refer to:
Computing
* Request for Comments, a memorandum on Internet standards
* Request for change, change management
* Remote Function Call, in SAP computer systems
* Rhye's and Fall of Civilization, a modification for Sid Meier's Civ ...
610, December 1973,
full text
/ref> A sample retrieval request:OPEN RESULTLIST ;
OPEN WEATHER ;
FOR WEATHER.STATION WITH REGION EQ 'MASSACHUSETTS'
FOR RESULTLIST.RESULT, OBSERVATION WITH TEMPERATURE.MAX GT '300' /* DEGREES KELVIN */
RESULT.CITY = STATION.CITY ;
RESULT.DATE = OBSERVATION.DATE ;
RESULT.TEMPERATURE = OBSERVATION.TEMPERATURE ;
END ;
END;
The Datacomputer hardware had a three-level store: primary core, secondary hard disk
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
, and tertiary mass storage. At the time, disk cost about $20/megabit, while mass stores, typically robotic magnetic tape
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...
systems, cost about $1/megabit. The service started in 1973 with disk storage only; tertiary storage using Ampex's Terabit Memory System (TMS) hardware, based on videotape technology, was to come on line in 1975.[Thomas Marill, Dale Stern, "The datacomputer—A network data utility", '' AFIPS '75 Proceedings, National Computer Conference'', May 19-22, 1975, Anaheim, California, {{doi, 10.1145/1499949.1500025, p. 389-395] In 1979, TMS's capacity was 175 billion bits (22 GB), and the total data stored was over 500 billion bits (62 GB)[Donald E. Eastlake III, Matthew Maltzman, Joanne Z. Sattley, Steven A. Zimmerman, "Datacomputer and SIP Operations: Semi-Annual Technical Report", Computer Corporation of America Technical report CCA-79-22, July 31, 197]
at DTIC
/ref>
Notes
External links
Email thread at Stanford AI Lab about the Datacomputer, 1976-1978
Data storage
ARPANET