{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T07:36:22Z","timestamp":1780472182902,"version":"3.54.1"},"reference-count":9,"publisher":"Association for Computing Machinery (ACM)","issue":"6","license":[{"start":{"date-parts":[[1974,6,1]],"date-time":"1974-06-01T00:00:00Z","timestamp":139276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.acm.org\/publications\/policies\/copyright_policy#Background"}],"content-domain":{"domain":["dl.acm.org"],"crossmark-restriction":true},"short-container-title":["Commun. ACM"],"published-print":{"date-parts":[[1974,6]]},"abstract":"<jats:p>This paper describes the design philosophy of HYDRA\u2014the kernel of an operating system for C.mmp, the Carnegie-Mellon Multi-Mini-Processor. This philosophy is realized through the introduction of a generalized notion of \u201cresource,\u201d both physical and virtual, called an \u201cobject.\u201d Mechanisms are presented for dealing with objects, including the creation of new types, specification of new operations applicable to a given type, sharing, and protection of any reference to a given object against improper application of any of the operations defined with respect to that type of object. The mechanisms provide a coherent basis for extension of the system in two directions: the introduction of new facilities, and the creation of highly secure systems.<\/jats:p>","DOI":"10.1145\/355616.364017","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T11:32:44Z","timestamp":1027769564000},"page":"337-345","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":276,"title":["HYDRA"],"prefix":"10.1145","volume":"17","author":[{"given":"W.","family":"Wulf","sequence":"first","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"E.","family":"Cohen","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W.","family":"Corwin","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Jones","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Levin","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Pierson","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F.","family":"Pollack","sequence":"additional","affiliation":[{"name":"Carnegie-Mellon Univ., Pittsburgh, PA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"320","published-online":{"date-parts":[[1974,6]]},"reference":[{"key":"e_1_2_1_1_2","doi-asserted-by":"publisher","DOI":"10.1145\/362258.362278"},{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.5555\/1243380"},{"key":"e_1_2_1_3_2","doi-asserted-by":"publisher","DOI":"10.1145\/363095.363143"},{"key":"e_1_2_1_4_2","first-page":"43","volume-title":"Cooperating sequential processes","author":"Dijkstra E.W.","year":"1968","unstructured":"Dijkstra , E.W. , Cooperating sequential processes . In Programming Languages, F. Genuys, (Ed.), Academic Press , New York , 1968 , pp. 43 - 112 . Dijkstra, E.W., Cooperating sequential processes. In Programming Languages, F. Genuys, (Ed.), Academic Press, New York, 1968, pp. 43-112."},{"key":"e_1_2_1_5_2","doi-asserted-by":"publisher","DOI":"10.1145\/365230.365252"},{"key":"e_1_2_1_6_2","volume-title":"Th. Carnegie-Mellon U.","author":"Jones A.K.","year":"1973","unstructured":"Jones , A.K. Protection in programming systems. Ph.D . Th. Carnegie-Mellon U. , 1973 . Jones, A.K. Protection in programming systems. Ph.D. Th. Carnegie-Mellon U., 1973."},{"key":"e_1_2_1_7_2","first-page":"27","volume-title":"Proc. AFIPS 1969 FJCC","volume":"35","author":"Lampson B.W.","unstructured":"Lampson , B.W. Dynamic Protection Structures , Proc. AFIPS 1969 FJCC , Vol. 35 , AFIPS Press, Montvale, N.J. pp. 27 - 38 . Lampson, B.W. Dynamic Protection Structures, Proc. AFIPS 1969 FJCC, Vol. 35, AFIPS Press, Montvale, N.J. pp. 27-38."},{"key":"e_1_2_1_8_2","volume-title":"Carnegie-Mellon U.","author":"Parnas D.L.","year":"1971","unstructured":"Parnas , D.L. On the criteria to be used in decomposing systems into modules. Comput. Sci. Dep. Rep ., Carnegie-Mellon U. , 1971 . Parnas, D.L. On the criteria to be used in decomposing systems into modules. Comput. Sci. Dep. Rep., Carnegie-Mellon U., 1971."},{"key":"e_1_2_1_9_2","first-page":"765","volume-title":"Proc. AFIPS","volume":"41","author":"Wulf W.A.","year":"1972","unstructured":"Wulf , W.A. , and Bell , C. G. C. mmp-a multi-mini-processor . Proc. AFIPS 1972 , FJCC. Vol. 41 , AFIPS Press, Montvale, N.J. pp. 765 - 777 . Wulf, W.A., and Bell, C. G. C.mmp-a multi-mini-processor. Proc. AFIPS 1972, FJCC. Vol. 41, AFIPS Press, Montvale, N.J. pp. 765-777."}],"container-title":["Communications of the ACM"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/355616.364017","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/dl.acm.org\/doi\/pdf\/10.1145\/355616.364017","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,17]],"date-time":"2025-06-17T19:00:00Z","timestamp":1750186800000},"score":1,"resource":{"primary":{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/355616.364017"}},"subtitle":["the kernel of a multiprocessor operating system"],"short-title":[],"issued":{"date-parts":[[1974,6]]},"references-count":9,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1974,6]]}},"alternative-id":["10.1145\/355616.364017"],"URL":"https:\/\/doi.org\/10.1145\/355616.364017","relation":{},"ISSN":["0001-0782","1557-7317"],"issn-type":[{"value":"0001-0782","type":"print"},{"value":"1557-7317","type":"electronic"}],"subject":[],"published":{"date-parts":[[1974,6]]},"assertion":[{"value":"1974-06-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}