The evolution of the Unix time-sharing system (1984)

by D M Ritchie
Venue:AT&T Bell Laboratories Technical Journal
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The C Programming Language

by Dennis M. Ritchie , 1988
"... The C programming language was devised in the early 1970s as a system implementation language for the nascent Unix operating system. Derived from the typeless language BCPL, it evolved a type structure; created on a tiny machine as a tool to improve a meager programming environment, it has become on ..."
Abstract - Cited by 1527 (16 self) - Add to MetaCart
The C programming language was devised in the early 1970s as a system implementation language for the nascent Unix operating system. Derived from the typeless language BCPL, it evolved a type structure; created on a tiny machine as a tool to improve a meager programming environment, it has become one of the dominant languages of today. This paper studies its evolution.

The Protection of Information in Computer Systems

by Jerome H. Saltzer, Michael D. Schroeder , 1975
"... This tutorial paper explores the mechanics of protecting computer-stored information from unauthorized use or modification. It concentrates on those architectural structures--whether hardware or software--that are necessary to support information protection. The paper develops in three main sections ..."
Abstract - Cited by 815 (2 self) - Add to MetaCart
This tutorial paper explores the mechanics of protecting computer-stored information from unauthorized use or modification. It concentrates on those architectural structures--whether hardware or software--that are necessary to support information protection. The paper develops in three main sections. Section I describes desired functions, design principles, and examples of elementary protection and authentication mechanisms. Any reader familiar with computers should find the first section to be reasonably accessible. Section II requires some familiarity with descriptor-based computer architecture. It examines in depth the principles of modern protection architectures and the relation between capability systems and access control list systems, and ends with a brief analysis of protected subsystems and protected objects. The reader who is dismayed by either the prerequisites or the level of detail in the second section may wish to skip to Section III, which reviews the state of the art and current research projects and provides suggestions for further reading. Glossary The following glossary provides, for reference, brief definitions for several terms as used in this paper in the context of protecting information in computers. Access The ability to make use of information stored in a computer system. Used frequently as a verb, to the horror of grammarians. Access control list A list of principals that are authorized to have access to some object. Authenticate To verify the identity of a person (or other agent external to the protection system) making a request.

A Fast File System for UNIX

by Marshall Kirk Mckusick, William N. Joy, Samuel J. Leffler, Robert S. Fabry - ACM Transactions on Computer Systems , 1984
"... A reimplementation of the UNIX file system is described. The reimplementation provides substantially higher throughput rates by using more flexible allocation policies that allow better locality of reference and can be adapted to a wide range of peripheral and processor characteristics. The new file ..."
Abstract - Cited by 566 (6 self) - Add to MetaCart
A reimplementation of the UNIX file system is described. The reimplementation provides substantially higher throughput rates by using more flexible allocation policies that allow better locality of reference and can be adapted to a wide range of peripheral and processor characteristics. The new file system clusters data that is sequentially accessed and provides two block sizes to allow fast access to large files while not wasting large amounts of space for small files. File access rates of up to ten times faster than the traditional UNIX file system are experienced. Long needed enhancements to the programmers’ interface are discussed. These include a mechanism to place advisory locks on files, extensions of the name space across file systems, the ability to use long file names, and provisions for administrative control of resource usage.
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Symbiotic Jobscheduling for a Simultaneous Multithreading Processor

by Allan Snavely, Dean Tullsen - In Eighth International Conference on Architectural Support for Programming Languages and Operating Systems , 2000
"... Simultaneous Multithreading machines fetch and execute instructions from multiple instruction streams to increase system utilization and speedup the execution of jobs. When there are more jobs in the system than there is hardware to support simultaneous execution, the operating system scheduler must ..."
Abstract - Cited by 338 (16 self) - Add to MetaCart
Simultaneous Multithreading machines fetch and execute instructions from multiple instruction streams to increase system utilization and speedup the execution of jobs. When there are more jobs in the system than there is hardware to support simultaneous execution, the operating system scheduler must choose the set of jobs to coschedule This paper demonstrates that performance on a hardware multithreaded processor is sensitive to the set of jobs that are coscheduled by the operating system jobscheduler. Thus, the full benefits of SMT hardware can only be achieved if the scheduler is aware of thread interactions. Here, a mechanism is presented that allows the scheduler to significantly raise the performance of SMT architectures. This is done without any advance knowledge of a workload's characteristics, using sampling to identify jobs which run well together.

The v distributed system

by David R. Cheriton , 1988
"... The V distributed System was developed at Stanford University as part of a research project to explore issues in distributed systems. Aspects of the design suggest important directions for the design of future operating systems and communication systems. ..."
Abstract - Cited by 312 (7 self) - Add to MetaCart
The V distributed System was developed at Stanford University as part of a research project to explore issues in distributed systems. Aspects of the design suggest important directions for the design of future operating systems and communication systems.

Ivy: A Read/Write Peer-to-Peer File System

by Athicha Muthitacharoen, Robert Morris, Thomer M. Gil, Benjie Chen , 2002
"... Ivy is a multi-user read/write peer-to-peer file system. Ivy has no centralized or dedicated components, and it provides useful integrity properties without requiring users to fully trust either the underlying peer-to-peer storage system or the other users of the file system. An Ivy file system con ..."
Abstract - Cited by 304 (12 self) - Add to MetaCart
Ivy is a multi-user read/write peer-to-peer file system. Ivy has no centralized or dedicated components, and it provides useful integrity properties without requiring users to fully trust either the underlying peer-to-peer storage system or the other users of the file system. An Ivy file system consists solely of a set of logs, one log per participant. Ivy stores its logs in the DHash distributed hash table. Each participant finds data by consulting all logs, but performs modifications by appending only to its own log. This arrangement allows Ivy to maintain meta-data consistency without locking. Ivy users can choose which other logs to trust, an appropriate arrangement in a semi-open peer-to-peer system. Ivy presents applications with a conventional file system interface. When the underlying network is fully connected, Ivy provides NFS-like semantics, such as close-to-open consistency. Ivy detects conflicting modifications made during a partition, and provides relevant version information to application-specific conflict resolvers. Performance measurements on a wide-area network show that Ivy is two to three times slower than NFS.
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Lightweight remote procedure call

by Brian N. Bershad, Thomas E. Anderson, Edward D. Lazowska, Henry M. Levy - ACM Transactions on Computer Systems , 1990
"... Lightweight Remote Procedure Call (LRPC) is a communication facility designed and optimized for communication between protection domains on the same machine. In contemporary small-kernel operating systems, existing RPC systems incur an unnecessarily high cost when used for the type of communication ..."
Abstract - Cited by 292 (27 self) - Add to MetaCart
Lightweight Remote Procedure Call (LRPC) is a communication facility designed and optimized for communication between protection domains on the same machine. In contemporary small-kernel operating systems, existing RPC systems incur an unnecessarily high cost when used for the type of communication that predominates-between protection domains on the same machine. This cost leads system designers to coalesce weakly related subsystems into the same protection domain, trading safety for performance. By reducing the overhead of same-machine communication, LRPC encourages both safety and performance. LRPC combines the control transfer and communication model of capability systems with the programming semantics and large-grained protection model of RPC. LRPC achieves a factor-of-three performance improvement over more traditional approaches based on independent threads exchanging messages, reducing the cost of same-machine communication to nearly the lower bound imposed by conventional hardware. LRPC has been integrated into the Taos operating system of the DEC SRC Firefly multiprocessor workstation.
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A Trace-Driven Analysis of the UNIX 4.2 BSD File System

by John Ousterhout, Herve Da Costa, David Harrison, John A. Kunze, Mike Kupfer, James G. Thompson , 1985
"... We analyzed the UNIX 4.2 BSD file system by recording userlevel activity in trace files and writing programs to analyze the traces. The tracer did not record individual read and write operations, yet still provided tight bounds on what information was accessed and when. The trace analysis shows that ..."
Abstract - Cited by 279 (5 self) - Add to MetaCart
We analyzed the UNIX 4.2 BSD file system by recording userlevel activity in trace files and writing programs to analyze the traces. The tracer did not record individual read and write operations, yet still provided tight bounds on what information was accessed and when. The trace analysis shows that the average file system bandwidth needed per user is low (a few hundred bytes per second). Most of the files accessed are open only a short time and are accessed sequentially. Most new information is deleted or overwritten within a few minutes of its creation. We also wrote a simulator that uses the traces to predict the performance of caches for disk blocks. The moderate-sized caches used in UNIX reduce disk traffic for file blocks by about 50%, but larger caches (several megabytes) can eliminate 90% or more of all disk traffic. With those large caches, large block sizes (16 kbytes or more) result in the fewest disk accesses. Trace-Driven Analysis of 4.2 BSD File System January 2, 1993 1...
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Password Security: A Case History

by Robert Morris, Ken Thompson - COMMUNICATIONS OF THE ACM , 1979
"... This paper describes the history of the design of the password security scheme on a remotely accessed time-sharing system. The present design was the result of countering observed attempts to penetrate the system. The result is a compromise between extreme security and ease of use. ..."
Abstract - Cited by 267 (0 self) - Add to MetaCart
This paper describes the history of the design of the password security scheme on a remotely accessed time-sharing system. The present design was the result of countering observed attempts to penetrate the system. The result is a compromise between extreme security and ease of use.
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Reflections on trusting trust

by Ken Thompson - Commun. ACM , 1984
"... I thank the ACM for this award. I can't help but feel that I am receiving this honour for tim-ing and serendipity as much as technical merit. UNIX swept into popularity with an industry-wide change from central main frames to autonomous minis. I suspect that Daniel Bobrow [1] would be here inst ..."
Abstract - Cited by 249 (0 self) - Add to MetaCart
I thank the ACM for this award. I can't help but feel that I am receiving this honour for tim-ing and serendipity as much as technical merit. UNIX swept into popularity with an industry-wide change from central main frames to autonomous minis. I suspect that Daniel Bobrow [1] would be here instead of me if he could not afford a PDP-10 and ad had to "settle " for a