J. E. Stoy and C. Strachey. OS6--an experimental operating system for a small computer. Part 2: input/output and filing system. The Computer Journal, 15(3), 1972.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the flushing and filling methods are common to all subtypes, so that generic facilities can deal with buffered streams efficiently, independently of where the bytes are coming from or going to. To our knowledge these streams were first in vented by the designers of the OS6 operating system [22]. In Modula 3 they are called readers and wrzters, and are described in Chapter 6 of [14] Garbage collection. Our system includes network wide reference counting garbage collection. For each exported network object, the runtime records the set of clients containing surrogates for the object (the ....

J. E. Stoy and C. Strachey. OS6--an experimental operating system for a small computer. Part 2: input/output and filing system. The Computer Journal, 15(3), 1972.

....Pilot stream facility is provided, comprising the following components: 1) The stream interface, which defines device independent operations for full duplex sequential access to a source sink of data. This is very similar in spirit to the stream facilities of other operating systems, such as OS6 [23] and UNIX [18] 2) A standard for stream components, which connect streams to various devices and or implement on thefly transformations of the data flowing through them. 3) A means for cascading a number of primitive stream components to provide a compound stream. There are two kinds of ....

Stoy, J.E., and Strachey, C. OS6---An experimental operating system for a small computer. Comput. J. 15, 2 and 3 (May, Aug. 1972).

....of its dependencies are visible, but the associated representation is not visible. In these situations, sound modular verification would be impossible, but dependencies save the day. Readers (and their output counterparts, writers) were invented by Stoy and Strachey for the OS6 operating system [47]. Although Stoy and Strachey never used the word object or class in describing them, they are in fact one of the most compelling examples of the engineering utility of object oriented programming. Each reader is an object with a buffer and a method for refilling the buffer. Different subtypes ....

J. E. Stoy and C. Strachey. OS6---an experimental operating system for a small computer. Part II: Input/output and filing system. The Computer Journal, 15(3):195--203, 1972.

....of the control program. The hardware and software mechanisms for the reliability of the control program are examined in Section 5.3 and the batch operating system is discussed in Section 5.4. There are few good readings on this topics and all of them are in the earlier books on operating systems [18, 25, 29, 80, 81, 79, 92, 93, 95]. The problem of protection is considered here as another facet of system reliability and is examined in Section 5.5. Hardware mechanisms that resolve the protection problem by protecting memory allocated to the program, by controlling access to the resources allocated to the procedures that make ....

E.J. Stoy and C. Strachey. Os-6 an experimental operating system for a small computer, part 2: Input-output and filing system. The Computer Journal, 15(3):195--203, 1972.

....of the control program. The hardware and software mechanisms for the reliability of the control program are examined in Section 5.3 and the batch operating system is discussed in Section 5.4. There are few good readings on this topics and all of them are in the earlier books on operating systems [18, 25, 29, 80, 81, 79, 92, 93, 95]. The problem of protection is considered here as another facet of system reliability and is examined in Section 5.5. Hardware mechanisms that resolve the protection problem by protecting memory allocated to the program, by controlling access to the resources allocated to the procedures that make ....

E.J. Stoy and C. Strachey. Os-6 an experimental operating system for a small computer, part 1: General principles and structure. The Computer Journal, 15(2):117--124, 1972.

....from the network. Class independent code can be common to all subclasses; for example, Wr.PutInt writes the ASCII representation of an integer into a writer s buffer. The Modula 3 design is described in Chapter 6 of Nelson s Modula 3 book [40] the original design is described by Stoy and Strachey [46]. We describe various aspects of the relevant interfaces as we need them for our examples. For each type of stream, the Modula 3 I O library provides two interfaces, a basic interface for simple clients, and an advanced interface that offers additional functionality (in particular, access to the ....

J. E. Stoy and C. Strachey. OS6---an experimental operating system for a small computer. Part II: Input/output and filing system. The Computer Journal, 15(3):195--203, 1972.

....generate a fingerprint from another fingerprint. In particular, never treat a fingerprint as text to be passed to FromText. # # 47 5I OStreams The interfaces Wr and Rd provide object oriented output and input streams, called writers and readers. These were invented by Stoy and Strachey in 1972 [18]. The versions presented here are slight modifications of the versions in the first Modula 3 book [13] We also present related interfaces for obtaining writers and readers connected to texts or files (TextWr, TextRd, FileWr,and FileRd) for accessing standard streams (Stdio) and for performing ....

J. E. Stoy and C. Strachey. OS6---an experimental operating system for a small computer. Part 2: Input/output and filing system. The Computer Journal, 15(3), May 1972. #

....gets the control; it restores the end of file function with the standard one and he may return to the master program. A stream is a set of standard functions and data areas. In a sense, it is a kind of package; the idea of i o stream was borrowed form OS6 by Strachey and Stoy of Oxford University [26], 27] In implementing the main frame UtiLisp system, macro assembly facilities were used to a great extent. Nevertheless, the list is not so difficult to read. As a simple example, the macro iflist is shown. This sequence checks whether the tag in a special register r is negative or not. ....

STOY J. E. and STRACHEY, C. OS6 - An Experimental Operating System for a Small Computer. Part 1: General Principles and Structure, Computer Journal, 15, 2 (1972), 117 -- 124.

....developing linguistic support for them seems to be a main line of development towards modular programming at that time. Zilles [Zil73] used the term procedural encapsulation to describe a similar program structuring technique used in the development of the experimental operating system OS6 [SS72a, SS72b] and noted that Using the technique of encapsulation, a data type is completely characterized by the set of operations defined on the data and the observable relationships between those operations . Liskov and Zilles [LZ74] coined the term abstract data type and introduced special modules, ....

....to variables . Prompted by Morris work, Zilles described in [Zil73] how his ideas about procedural encapsulation could be expressed in a language with support for function returning functions. He used as an example the implementation of streams in the experimental operating system OS6 [SS72a, SS72b] A stream is uniformly represented by a vector of entry points, one for each of the above operations. And, because the OS6 system language does not provide true function returning functions, the state information needed by these entries ( is also stored in the vector. Mesa was one of ....

J. E. Stoy and C. Strachey. OS6 --- an experimental operating system for a small computer. II. input/output and filing system. The Computer Journal, 15(3):195--203, August 1972.

....and developing linguistic support for them seems to be a main line of development towards modular programming at that time. Zilles [Zil73] used the term procedural encapsulation to describe a similar program structuring technique used in the development of the experimental operating system OS6 [SS72a, SS72b] and noted that Using the technique of encapsulation, a data type is completely characterized by the set of operations defined on the data and the observable relationships between those operations . Liskov and Zilles [LZ74] coined the term abstract data type and introduced special ....

....assigned to variables . Prompted by Morris work, Zilles described in [Zil73] how his ideas about procedural encapsulation could be expressed in a language with support for function returning functions. He used as an example the implementation of streams in the experimental operating system OS6 [SS72a, SS72b] A stream is uniformly represented by a vector of entry points, one for each of the above operations. And, because the OS6 system language does not provide true function returning functions, the state information needed by these entries ( is also stored in the vector. Mesa was ....

J. E. Stoy and C. Strachey. OS6 --- an experimental operating system for a small computer. I. general principles and structure. The Computer Journal, 15(2):117--124, May 1972.

....that dynamically restricts continuation based control transfer [Felleisen et al. 88] This scoping mechanism provides the isolation that one desires in an operating system. In fact, the OS6 operating system and its implementation language BCPL used a similar dynamic scoping for control transfer [Stoy Strachey 72] A functional continuation differs from the abortive continuations produced by call cc in that the invocation of a functional continuation does not discard the current evaluation context. Instead, the functional continuation can return a value to its caller. However, the control operation that ....

J. E. Stoy and C. Strachey. OS6---An Experimental Operating System for a Small Computer. The Computer Journal, 15(2):117-124,15(3):195-203, 1972. BIBLIOGRAPHY 133

....invoking the flushing and filling methods are common to all subtypes, so that generic facilities can deal with buffered streams efficiently, independently of where the bytes are coming from or going to. To our knowledge these streams were first invented by the designers of the OS6 operating system[26]. In Modula 3 they are called readers and writers[18] Because we use readers and writers, our interface between stubs and protocol specific communication code (which we call transports) is quite simple. This choice was initially controversial, and viewed as a likely source of performance ....

J. E. Stoy and C. Strachey. OS6---an experimental operating system for a small computer. Part 2: input/output and filing system. The Computer Journal, 15(3):195--203, 1972.

....network protocols. These were established by the BCPL operating system and did not change after 1976; they constitute the interface between the various programming environments. Operating systems The first Alto operating system [29] usually called the OS, is derived from Stoy and Strachey s 056 [47]. It provides a disk file and directory system, a keyboard handler, a teletype simulator for the screen, a standard stream abstraction for input output, a program loader, and a free storage allocator. There is no provision for multiple processes, virtual memory, or protection, although the first ....

J. E. Stoy and C. Strachey. OS6-an experimental operating system for a small computer. Computer Journal, 15(2 and 3), May and August 1972.

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