DOCSLIB.ORG

United States Patent 19 11 Patent Number: 5,628,017 Kimmerly Et Al

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
United States Patent 19 11 Patent Number: 5,628,017 Kimmerly Et Al USO05628O17A United States Patent 19 11 Patent Number: 5,628,017 Kimmerly et al. 45 Date of Patent: May 6, 1997 54 METHOD AND SYSTEM FOR PROVIDING "Windows System Timers; Icon Questions; Rotating a Bit EVENTRESPONSE CAPABILITESTO map; Handling a Joystick” by Paul Bonneau Windows-DOS PSEUDOCODE Developer's Journal Oct. 1992 v3 n1.0. p. 27(12). "Dusting Off Applications” by Ronald Albury, UNIX 75 Inventors: Randy S. Kimmerly; Robert E. Saile, Review Jan. 1991 v9 n1 p. 40(5). both of Redmond, Wash. “Within Technologies Inc: Realizer 1.0", Julian Milenbach PC Week Sep. 16, 1991 v8 n37 p. 103(3). 73) Assignee: Microsoft Corporation, Redmond, "Microsoft Unveils Code-Crunching C 7.0 Compiler” by Wash. Karen D. Moser, PC Week Sep. 2, 1991 v8 n35 p. 1(2). 21 Appl. No.: 593,544 (List continued on next page.) Primary Examiner-Alvin E. Oberley 22 Fied: Jan. 29, 1996 Assistant Examiner Michael T. Richey Related U.S. Application Data Attorney, Agent, or Firm-Seed and Berry LLP 57 ABSTRACT I63) Continuation of Ser. No. 31,566, Mar. 15, 1993, abandoned. A method and system for providing event-response and 51 Int, Cl- imm. G06F 9/40 monitoring capabilities to a pseudocode program operating (52) U.S. Cl. ......................... 395/704; 395/707; 395/682; in a message or event-based operating environment. The 395/685; 364/280.8; 364/280.9 method and system allow the pseudocode program to asyn 58) Field of Search ................................... 395/700, 650, chronously respond to events via one or more trap routines 395/682, 685, 704, 707; 364/280.8, 280.9 located in the pseudocode program. The method and system also allow the pseudocode program to synchronously moni 56) References Cited tor events and receive parameters from operating system routines via callback routines located in the pseudocode U.S. PATENT DOCUMENTS program. The system includes an execution engine for 4.866,638 9/1989 Cosentino et al....................... 364/521 executing instructions of the pseudocode program. An 4,974,159 11/1990 Hargrove et al..... ... 364/200 event-response routine in the pseudocode program includes 5,148,544 9/1992 Cutler et al. ..... ... 395/725 instructions for responding to the event. An event-response 5,218,712 6/1993 Cutler et al. ..... ... 395/800 dispatcher is adapted to receive information identifying the 5,237,684 8/1993 Record et al. .......................... 395/650 event-response routine, save the execution state of the OTHER PUBLICATIONS execution engine, cause the execution engine to execute the event-response routine, and restore the execution state of the Microsoft C/C++ Programming Techniques, 3:43–53 execution engine that existed before the event-response (1991). routine was executed. A transfer routine accessible in Microsoft Windows Software Development Kit, Program response to a call triggered by the event accesses the mer's Reference, vol. 2: Functions:535-539, 625-626, event-response dispatcher, passes information identifying 894-899,956-958 (1992). the event-response routine to the event-response dispatcher, Petzold, Charles, "Programming Windows 3.1. Third Edi and returns control to the execution engine after the event tion.” The Microsoft Guide to Writing Applications for response dispatcher restores the state of the execution engine Windows 3.1:175-193, 907-929 (1992). and returns to the transfer routine. Microsoft Visual Basic Programming System for Windows: Professional Features:7-14, 57-63 (1992). 21 Claims, 7 Drawing Sheets Lldetector Routix Octics Eye Call trap dispatcher likalifier U 5,628,017 Page 2 OTHER PUBLICATIONS "Strategies for Optimizing Assembly Language Programs” “FoxPro 2.0: What's in it for you?” Alan Y. Griver et al. by Ray Duncan, PC Magazine Nov. 26, 1991 v10 n20 p. Data Based Advisor Jun. 1991 v9 nó p. 96(3). 511(4). "McDonnell Douglas Presses Software Vendors to Continue with Tuxedo Development”. Computergram International "Microsoft Brings Back P-Code; Technique Holds Promise Jun. 27, 1991 n1706. for Future Operating Systems” by Larry J. Seltzer PC Week “A Preview of MicroSoft cfc. 7 and the Microsoft Foun May 11, 1992 v9 n19 p.61(2). dation Classes for Windows" by Richard Hale Shaw, Microsoft Systems Journal Mar.-Apr. 1992 v7 n2 p. 43(13). “A Portable Menu Compiler: Part 5: CMENU” by Leon "Realizer Opens Windows” by Bruce Schatyman. DBMS Zolman, C Users Journal Aug. 1992 v10 n8 p116(11). Nov. 1991 v4 n12 p. 42(2). "Hook Up with Relational Databases"; Here's Why You “Are your Ready for Cutting Edge COBOL?” by Neel Snell Should Link Your Procedural-Language Product to a Datamation Oct. 15, 1992 v38 n21 p77(7). RDBMS, Data Based Advisor Feb. 1992 v10 n2 p. 74(9). "GUI Development Tools Take Giant Leap to Fourth Gen “The Xview Notifier” by Dan Heller, UnixWorld Jul. 1990, eration” by Steve Gibson, InfoWorld Sep. 2, 1991 v13 n35 pp. 123-133. p. 35(1). "Threaded Pseudo Code Gives Microsoft Visual Basic Its Shaw, R., “A Preview of Microsoft C/C++ 7 and the Edge" by Steve Gibson, InfoWorld Jul. 1, 1991 v13 n26 p. Microsoft Foundation Classes for Windows'. Microsoft 30(1). Systems Journal, Mar, 1992, pp. 43–55. U.S. Patent May 6, 1997 Sheet 1 of 7 5,628,017 10 CPU / Registers Figure 1 U.S. Patent May 6, 1997 Sheet 3 of 7 5,628,017 46 Compile Main Program Into Pseudocode 48 Call DLL Detector Routine 50 Pass Trap Dispatcher Pointer 52 Pass Trap Routine Identifie 54 Pass Activate Flag 56 Figure 3 Return To Main Program More Trap Routines? 60 Execute Pseudocode Program U.S. Patent May 6, 1997 Sheet 4 of 7 5,628,017 DLL Detector 62 Routine Detects Event 64 Call Trap Dispatcher 66 Pass Trap Routine Identifier 68 Store Execution Engine State Find 70 Associated Trap Routine 72 Execute Trap Routine Figure 4 Restore Execution Engine State 76 Return To DLL Detector Routine 78 Return To Program U.S. Patent May 6, 1997 Sheet 5 of 7 5,628,017 06 |zaupnosi 88 uue130J? 98 UueI3OJA U.S. Patent May 6, 1997 Sheet 6 of 7 5,628,017 98 Call Operating System (OS) Routine Pass OS Routine 00 Parameters & Thunk Address To OS Routine 02 Execute OS Routine 04 Return To Callback Thunk Figure 6A Pass Callback 106 Routine Parameters 08 Pass Callback Routine Index 10 Pass Execution Engine Data Segment Address U.S. Patent May 6, 1997 Sheet 7 of 7 5,628,017 Call Callback Dispatcher Save Execution Engine State Execute Callback Routine Restore Main Execution Engine State Return To Callback Thunk Return. To OS Routine Return To Main Program Execution 5,628,017 1. 2 METHOD AND SYSTEM FOR PROVIDING Like most programs, the execution engine interacts with EVENTRESPONSE CAPABILITESTO a computer operating system to access hardware devices of PSEUDOCODE the computer. Most advanced operating systems, such as the Microsoft Windows operating system and OS/2, are event CROSS-REFERENCE TO RELATED or message-based multitasking systems. In such event-based APPLICATION systems, the user interacts with windows, menus, and con trols in a user interface of a program. User-generated events, This application is a continuation of U.S. patent applica such as mouse clicks and keystrokes, place “messages' in tion Ser. No. 08/031,566, filed Mar. 15, 1993, now aban the program's message queue. The program uses a message doned. loop to get messages from the queue and send the messages 10 to the appropriate window for handling by a window pro TECHNICAL FIELD cedure. Each window is associated with a window procedure The present invention relates generally to computer pro that responds to the messages received from the message gram interfacing, and more particularly to interfacing loop. Alternatively, messages can be sent directly from an pseudocode programs with an event-based operating envi operating system routine to the window procedure without 15 using the message queue if the operating system routine is rOnment. given a pointer to the window procedure. BACKGROUND OF THE INVENTION The window procedure is a type of routine known as a callback routine. In general, a callback routine is a routine A computer program is usually written in a language other that receives messages or other information from another than the machine language used by the computer to execute routine, such as an operating system routine. The informa the program. The reason is that machine language is not tion received can be asynchronous relative to the execution designed for human communication. Because computers of the callback routine, that is, the information is received at utilize two-state storage and switching devices, sequences of unexpected times. System interrupts and messages received binary digits provide the most natural form for expressing based on user input, i.e. window messages, are examples of program instructions. However, sequences of binary digits 25 asynchronous information. The information received also are very unnatural for humans to construct or to understand. can be synchronous, that is, information received according The language in which a computer program is written is to a synchronous execution of instructions. Synchronous called source code. A translator is used to translate the information results when a program calls a routine, such as source code into machine language understandable by the an operating system routine and tells the operating system computer. In some systems, a first translator translates the 30 routine to "call back” to a callback routine in the program. Source code into an intermediate language, such as an The call back to the callback routine passes information assembly language, and a second translator translates the produced by execution of the operating system routine.
Load more

Recommended publications
  • Open WATCOM Programmer's Guide
    this document downloaded from... Use of this document the wings of subject to the terms and conditions as flight in an age stated on the website. of adventure for more downloads visit our other sites Positive Infinity and vulcanhammer.net chet-aero.com Watcom FORTRAN 77 Programmer's Guide Version 1.8 Notice of Copyright Copyright 2002-2008 the Open Watcom Contributors. Portions Copyright 1984-2002 Sybase, Inc. and its subsidiaries. All rights reserved. Any part of this publication may be reproduced, transmitted, or translated in any form or by any means, electronic, mechanical, manual, optical, or otherwise, without the prior written permission of anyone. For more information please visit http://www.openwatcom.org/ Portions of this manual are reprinted with permission from Tenberry Software, Inc. ii Preface The Watcom FORTRAN 77 Programmer's Guide includes the following major components: · DOS Programming Guide · The DOS/4GW DOS Extender · Windows 3.x Programming Guide · Windows NT Programming Guide · OS/2 Programming Guide · Novell NLM Programming Guide · Mixed Language Programming · Common Problems Acknowledgements This book was produced with the Watcom GML electronic publishing system, a software tool developed by WATCOM. In this system, writers use an ASCII text editor to create source files containing text annotated with tags. These tags label the structural elements of the document, such as chapters, sections, paragraphs, and lists. The Watcom GML software, which runs on a variety of operating systems, interprets the tags to format the text into a form such as you see here. Writers can produce output for a variety of printers, including laser printers, using separately specified layout directives for such things as font selection, column width and height, number of columns, etc.
    [Show full text]
  • COMPILING FUNCTIONAL PROGRAMMING CONSTRUCTS to a LOGIC ENGINE by Harvey Abramson and Peter Ludemann Technical Report 86-24 November 1986
    COMPILING FUNCTIONAL PROGRAMMING CONSTRUCTS TO A LOGIC ENGINE by Harvey Abramson and Peter Ludemann Technical Report 86-24 November 1986 Compiling Functional Programming Constructs to a Logic Engine Harvey Abramson t and Peter Ltidemann:I: Department of Computer Science University of British Columbia Vancouver, B.C., Canada V6T 1W5 Copyright © 1986 Abstract In this paper we consider how various constructs used in functional programming can be efficiently translated to code for a Prolog engine (designed by Ltidemann) similar in spirit but not identical to the Warren machine. It turns out that this Prolog engine which contains a delay mechanism designed to permit co­ routining and sound implementation of negation is sufficient to handle all common functional programming constructs; indeed, such a machine has about the same efficiency as a machine designed specifically for a functional programming language. This machine has been fully implemented. t Present address: Department of Computer Science, Bristol University, Bristol, England . f Present address: IBM Canada Ltd., 1 Park Centre, 895 Don Mills Road, North York, Ontario, Canada M3C 1W3 The proposals for combining the two paradigms Compiling Functional Programming have been roughly classified in [BoGi86] as being Constructs to a Logic Engine either functional plus logic or logic plus functional. Harvey Abramson t and Peter Ltidemanni In the former approach, invertibility, nondeterminism Department of Computer Science and unification are added to some higher order functional language; in the latter approach, first-order University of British Columbia functions are added to a first-order logic with an Vancouver, B.C., Canada V6T lWS equality theory. We do not take any position as to Copyright© 1986 which approach is best, but since a logic machine already deals with unification, nondeterminism and invertibility, we have taken, from an implementation Abstract viewpoint, the logic plus functional approach.
    [Show full text]
  • Parameter Passing, Generics, Exceptions
    Lecture 9: Parameter Passing, Generics and Polymorphism, Exceptions COMP 524 Programming Language Concepts Stephen Olivier February 12, 2008 Based on notes by A. Block, N. Fisher, F. Hernandez-Campos, and D. Stotts The University of North Carolina at Chapel Hill Parameter Passing •Pass-by-value: Input parameter •Pass-by-result: Output parameter •Pass-by-value-result: Input/output parameter •Pass-by-reference: Input/output parameter, no copy •Pass-by-name: Effectively textual substitution The University of North Carolina at Chapel Hill 2 Pass-by-value int m=8, i=5; foo(m); print m; # print 8 proc foo(int b){ b = b+5; } The University of North Carolina at Chapel Hill 3 Pass-by-reference int m=8; foo(m); print m; # print 13 proc foo(int b){ b = b+5; } The University of North Carolina at Chapel Hill 4 Pass-by-value-result int m=8; foo(m); print m; # print 13 proc foo(int b){ b = b+5; } The University of North Carolina at Chapel Hill 5 Pass-by-name •Arguments passed by name are re-evaluated in the caller’s referencing environment every time they are used. •They are implemented using a hidden-subroutine, known as a thunk. •This is a costly parameter passing mechanism. •Think of it as an in-line substitution (subroutine code put in-line at point of call, with parameters substituted). •Or, actual parameters substituted textually in the subroutine body for the formulas. The University of North Carolina at Chapel Hill 6 Pass-by-name array A[1..100] of int; array A[1..100] of int; int i=5; int i=5; foo(A[i], i); foo(A[i]); print A[i]; #print A[6]=7
    [Show full text]
  • Programming Languages
    ◦ ◦◦◦ TECHNISCHE UNIVERSITAT¨ MUNCHEN¨ ◦◦◦◦ ◦ ◦ ◦◦◦ ◦◦◦◦ ¨ ¨ ◦ ◦◦ FAKULTAT FUR INFORMATIK Programming Languages Multiple Inheritance Dr. Axel Simon and Dr. Michael Petter Winter term 2012 Multiple Inheritance 1 / 29 Outline Inheritance Principles 1 Interface Inheritance 2 Implementation Inheritance 3 Liskov Substition Principle and Shapes C++ Object Heap Layout 1 Basics 2 Single-Inheritance Excursion: Linearization 3 Virtual Methods 1 Ambiguous common parents 2 Principles of Linearization C++ Multiple Parents Heap Layout 3 Linearization algorithm 1 Multiple-Inheritance 2 Virtual Methods 3 Common Parents Discussion & Learning Outcomes Multiple Inheritance 2 / 29 “Wouldn’t it be nice to inherit from several parents?” Multiple Inheritance Inheritance Principles 3 / 29 Interface vs. Implementation inheritance The classic motivation for inheritance is implementation inheritance Code reusage Child specializes parents, replacing particular methods with custom ones Parent acts as library of common behaviours Implemented in languages like C++ or Lisp Code sharing in interface inheritance inverts this relation Behaviour contract Child provides methods, with signatures predetermined by the parent Parent acts as generic code frame with room for customization Implemented in languages like Java or C# Multiple Inheritance Inheritance Principles 4 / 29 Interface Inheritance DropDownList refresh() ActionObserver MyDDL changed() changed() Multiple Inheritance Inheritance Principles 5 / 29 Implementation inheritance PowerShovel FrontLoader actuate() actuate()
    [Show full text]
  • Subroutines and Control Abstraction8 8.3.2 Call by Name
    Subroutines and Control Abstraction8 8.3.2 Call by Name Call by name implements the normal-order argument evaluation described in Section 6.6.2. A call-by-name parameter is re-evaluated in the caller’s referencing environment every time it is used. The effect is as if the called routine had been textually expanded at the point of call, with the actual parameter (which may be a complicated expression) replacing every occurrence of the formal parameter. To avoid the usual problems with macro parameters, the “expansion” is defined to include parentheses around the replaced parameter wherever syntactically valid, and to make “suitable systematic changes” to the names of any formal parame- ters or local identifiers that share the same name, so that their meanings never conflict [NBB+63, p. 12]. Call by name is the default in Algol 60; call by value is available as an alternative. In Simula call by value is the default; call by name is the alternative. Toimplement call by name,Algol 60 implementations pass a hidden subroutine that evaluates the actual parameter in the caller’s referencing environment. The hidden routine is usually called a thunk.2 In most cases thunks are trivial. If an actual parameter is a variable name, for example, the thunk simply reads the EXAMPLE 8.68 variable from memory. In some cases, however, a thunk can be elaborate. Perhaps Jensen’s device the most famous occurs in what is known as Jensen’s device, named after Jørn Jensen [Rut67]. The idea is to pass to a subroutine both a built-up expression and one or more of the variables used in the expression.
    [Show full text]
  • Design, Semantics and Implementation of the Ptolemy
    Computer Science Technical Reports Computer Science Summer 7-31-2015 Design, Semantics and Implementation of the Ptolemy Programming Language: A Language with Quantified yT ped Events Hridesh Rajan Iowa State University, [email protected] Gary T. Leavens University of Central Florida Follow this and additional works at: http://lib.dr.iastate.edu/cs_techreports Part of the Programming Languages and Compilers Commons Recommended Citation Rajan, Hridesh and Leavens, Gary T., "Design, Semantics and Implementation of the Ptolemy Programming Language: A Language with Quantified Typed Events" (2015). Computer Science Technical Reports. 376. http://lib.dr.iastate.edu/cs_techreports/376 This Article is brought to you for free and open access by the Computer Science at Iowa State University Digital Repository. It has been accepted for inclusion in Computer Science Technical Reports by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Design, Semantics and Implementation of the Ptolemy Programming Language: A Language with Quantified yT ped Events Abstract Implicit invocation (II) and aspect-oriented (AO) languages provide software designers with related but distinct mechanisms and strategies for decomposing programs into modules and composing modules into systems. II languages have explicitly announced events that run registered observer methods. AO languages have implicitly announced events that run method-like but more powerful advice. A limitation of II languages is their inability to refer to a large set of events succinctly. They also lack the expressive power of AO advice. Limitations of AO languages include potentially fragile dependence on syntactic structure that may hurt maintainability, and limits on the available set of implicit events and the reflective contextual information available.
    [Show full text]
  • On Matching Binary to Source Code
    ON MATCHING BINARY TO SOURCE CODE Arash Shahkar A thesis in The Department of Concordia Institute for Information Systems Engineering Presented in Partial Fulfillment of the Requirements For the Degree of Master of Applied Science in Information Systems Security at Concordia University Montréal, Québec, Canada March 2016 c Arash Shahkar, 2016 Concordia University School of Graduate Studies This is to certify that the thesis prepared By: Arash Shahkar Entitled: On Matching Binary to Source Code and submitted in partial fulfillment of the requirements for the degree of Master of Applied Science (Information Systems Security) complies with the regulations of this University and meets the accepted standards with respect to originality and quality. Signed by the final examining committee: Dr. Jia Yuan Yu Chair Dr. Lingyu Wang Examiner Dr. Zhenhua Zhu External Examiner Dr. Mohammad Mannan Supervisor Approved Chair of Department or Graduate Program Director 2016 Dr. Amir Asif, Dean Faculty of Engineering and Computer Science Abstract On Matching Binary to Source Code Arash Shahkar Reverse engineering of executable binary programs has diverse applications in computer security and forensics, and often involves identifying parts of code that are reused from third party software projects. Identification of code clones by comparing and fingerprinting low-level binaries has been explored in various pieces of work as an effective approach for accelerating the reverse engineering process. Binary clone detection across different environments and computing platforms bears significant challenges, and reasoning about sequences of low-level machine in- structions is a tedious and time consuming process. Because of these reasons, the ability of matching reused functions to their source code is highly advantageous, de- spite being rarely explored to date.
    [Show full text]
  • BEA TUXEDO Workstation Guide
    BEA TUXEDO Workstation Guide BEA TUXEDO Release 6.5 Document Edition 6.5 February 1999 Copyright Copyright © 1999 BEA Systems, Inc. All Rights Reserved. Restricted Rights Legend This software and documentation is subject to and made available only pursuant to the terms of the BEA Systems License Agreement and may be used or copied only in accordance with the terms of that agreement. It is against the law to copy the software except as specifically allowed in the agreement. This document may not, in whole or in part, be copied photocopied, reproduced, translated, or reduced to any electronic medium or machine readable form without prior consent, in writing, from BEA Systems, Inc. Use, duplication or disclosure by the U.S. Government is subject to restrictions set forth in the BEA Systems License Agreement and in subparagraph (c)(1) of the Commercial Computer Software-Restricted Rights Clause at FAR 52.227-19; subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause at DFARS 252.227-7013, subparagraph (d) of the Commercial Computer Software--Licensing clause at NASA FAR supplement 16-52.227-86; or their equivalent. Information in this document is subject to change without notice and does not represent a commitment on the part of BEA Systems. THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FURTHER, BEA Systems DOES NOT WARRANT, GUARANTEE, OR MAKE ANY REPRESENTATIONS REGARDING THE USE, OR THE RESULTS OF THE USE, OF THE SOFTWARE OR WRITTEN MATERIAL IN TERMS OF CORRECTNESS, ACCURACY, RELIABILITY, OR OTHERWISE.
    [Show full text]
  • Sloth: Being Lazy Is a Virtue (When Issuing Database Queries)
    Sloth: Being Lazy is a Virtue (When Issuing Database Queries) The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Cheung, Alvin, Samuel Madden, and Armando Solar-Lezama. “Sloth.” Proceedings of the 2014 ACM SIGMOD International Conference on Management of Data - SIGMOD ’14 (2014), June 22– 27, 2014, Snowbird, UT, USA. ACM, New York, NY, USA p.931-942. As Published http://dx.doi.org/10.1145/2588555.2593672 Publisher Association for Computing Machinery Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/90361 Terms of Use Creative Commons Attribution-Noncommercial-Share Alike Detailed Terms http://creativecommons.org/licenses/by-nc-sa/4.0/ Sloth: Being Lazy is a Virtue (When Issuing Database Queries) Alvin Cheung Samuel Madden Armando Solar-Lezama MIT CSAIL {akcheung,madden,asolar}@csail.mit.edu ABSTRACT Google reported in 2006 that an extra 0.5 second of latency reduced Many web applications store persistent data in databases. During the overall traffic by 20% [6]. These numbers are likely worse execution, such applications spend a significant amount of time on modern computers where pages load faster and faster, making communicating with the database for retrieval and storing of per- it increasingly important to reduce the amount of time spent on sistent data over the network. These network round trips represent database queries. Second, ORM frameworks can greatly increase a significant fraction of the overall execution time for many appli- load times by performing additional queries to retrieve objects that cations and as a result increase their latency.
    [Show full text]
  • O O S E E Object Orientation
    Classification [7] O OSE E + classes + inheritance Object Orientation object−based class−based object−oriented Operating-System Engineering Operating-System Engineering — Object Orientation 2 Object-Oriented Design [2] Object-Based • implies the capability of data abstraction { methods provide access to attributes method { attributes represent instance variables Object-oriented design is a method of design encompassing the process of object-oriented decomposition and a notation for depicting both logical and attribute • methods define the object’s external interface object physical as well as static and dynamic models of the systems under design. { similar to an abstract data type (ADT) • objects are unique instances, having only in common the need for memory Operating-System Engineering — Object Orientation 1 Operating-System Engineering — Object Orientation 3 Class-Based Object Orientation = Objects + Classes + Inheritance • objects are instances of classes • an object-oriented programming language must provide linguistic support { a class defines a set of common properties methods { properties are attributes of a class { it must enable the programmers to describe common properties of objects { classes may be compared to types ∗ such a language is referred to as an object-based programming language { it is called object-oriented only if class hierarchies can be built by inheritance ∗ • a meta-description specifies the interface instances so that the objects can be instances of classes that have been inherited { it allows the modeling of an object as a polymorphous entity { describing a uniform management class { indicating further data abstractions • object orientation is unattainable using imperative programming languages1 • depending on the programming language employed, a class may be an ADT 1Notwithstanding, from time to time there are comments stating the development of object-oriented systems using e.g.
    [Show full text]
  • How Windows Works 97
    11_0789734249_CH07.qxd 10/17/05 2:11 PM Page 96 96 PART 3 HOW SOFTWARE WORKS CHAPTER How Windows 7 Works 11_0789734249_CH07.qxd 10/17/05 2:11 PM Page 97 CHAPTER 7 HOW WINDOWS WORKS 97 THE Windows operating system is more than just a pretty face. Sure, it’s cute, with all the tiny pictures called icons, sound effects, your personal color scheme, and the capability to drag things around like pull-toys. But behind that face is a stern taskmaster. Windows XP, Microsoft’s advanced version of Windows, is not your father’s operating system. Earlier versions of the consumer level of Windows were built on top of DOS, an elementary operating system for small computers and modest programs that came with the first PCs. DOS was inept at graphics, color, and sound, features that are commonplace in Windows. More importantly, DOS was intended to run only one program at a time. There was no competition by different programs for the attention of the processor, memory, and drive storage. Computers back then might not have had much memory, but any program loaded into that memory had the run of the place. Now, these programs were expected to play nice and share such toys as RAM and the CPU. They didn’t, of course. And when programs trampled on another program’s RAM, Windows didn’t know what to do and collapsed into the dreaded Blue Screen of Death. With XP, Windows finally got smart—and sneaky. As you’ll discover in this chapter, Windows became enormously more stable when it used pretend computers so that each program thought it was the only program running on the PC.
    [Show full text]
  • CS 251: Programming Languages Fall 2015 ML Summary, Part 5
    CS 251: Programming Languages Fall 2015 ML Summary, Part 5 These notes contain material adapted from notes for CSE 341 at the University of Washington by Dan Grossman. They have been converted to use SML instead of Racket and extended with some additional material by Ben Wood. Contents Introduction to Delayed Evaluation and Thunks .......................... 1 Lazy Evaluation with Delay and Force ................................. 2 Streams .................................................... 4 Memoization ................................................. 6 Integrating Lazy Evaluation into the Language ........................... 11 Introduction to Delayed Evaluation and Thunks A key semantic issue for a language construct is when are its subexpressions evaluated. For example, in ML (and similarly in Racket and most but not all programming languages), given e1 e2 ... en we evaluate the function arguments e2, ..., en once before we execute the function body and given a function fn ... => ... we do not evaluate the body until the function is called. This rule (\evaluate arguments in advance") goes by many names, including eager evaluation and call-by-value. (There is a family of names for parameter-passing styles referred to with call-by-.... Many are not particularly illuminating or downright confusing names, but we note them here for reference.) We can contrast eager evaluation with how if e1 then e2 else e3 works: we do not evaluate both e2 and e3. This is why: fun iffy x y z = if x then y else z is a function that cannot be used wherever
    [Show full text]