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IEEE P1003.0 Draft 13 - September 1991 Copyright (c) 1991 by the Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street New York, NY 10017, USA All rights reserved as an unpublished work. This is an unapproved and unpublished IEEE Standards Draft, subject to change. The publication, distribution, or copying of this draft, as well as all derivative works based on this draft, is expressly prohibited except as set forth below. Permission is hereby granted for IEEE Standards Committee participants to reproduce this document for purposes of IEEE standardization activities only, and subject to the restrictions contained herein. Permission is hereby also granted for member bodies and technical committees of ISO and IEC to reproduce this document for purposes of developing a national position, subject to the restrictions contained herein. Permission is hereby also granted to the preceding entities to make limited copies of this document in an electronic form only for the stated activities. The following restrictions apply to reproducing or transmitting the document in any form: 1) all copies or portions thereof must identify the document's IEEE project number and draft number, and must be accompanied by this entire notice in a prominent location; 2) no portion of this document may be redistributed in any modified or abridged form without the prior approval of the IEEE Standards Department. Other entities seeking permission to reproduce this document, or any portion thereof, for standardization or other activities, must contact the IEEE Standards Department for the appropriate license. Use of information contained in this unapproved draft is at your own risk. IEEE Standards Department Copyright and Permissions 445 Hoes Lane, P.O. Box 1331 Piscataway, NJ 08855-1331, USA +1 (908) 562-3800 +1 (908) 562-1571 [FAX] P1003.0 Draft 13 STANDARDS PROJECT Draft Guide to the POSIX Open Systems Environment Sponsor Technical Committee on Operating Systems and Application Environments of the IEEE Computer Society Abstract: IEEE Std 1003.0-199x presents an overview of open system concepts and their application. Information is provided to persons evaluating systems on the existence of, and interrelationships among, application software standards, with the objective of enabling application portability and system interoperability. A framework is presented that identifies key information system interfaces involved in application portability and system interoperability and describes the services offered across these interfaces. Standards or standards activities associated with the services are identified where they exist, or are in progress. Gaps are identified where POSIX Open Systems Environment (OSE) requirements are not being addressed currently. Finally, the OSE profile concept is discussed with examples from several application domains. Keywords: application portability, open systems environments, profiles, POSIX P1003.0 / D13 September 1991 Copyright (c) 1991 by the Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street New York, NY 10017, USA All rights reserved. _T_h_i_s _i_s _a_n _u_n_a_p_p_r_o_v_e_d _I_E_E_E _S_t_a_n_d_a_r_d_s _D_r_a_f_t, _s_u_b_j_e_c_t _t_o _c_h_a_n_g_e. _P_e_r_m_i_s_s_i_o_n _i_s _h_e_r_e_b_y _g_r_a_n_t_e_d _f_o_r _I_E_E_E _S_t_a_n_d_a_r_d_s _C_o_m_m_i_t_t_e_e _p_a_r_t_i_c_i_p_a_n_t_s _t_o _r_e_p_r_o_d_u_c_e _t_h_i_s _d_o_c_u_m_e_n_t _f_o_r _p_u_r_p_o_s_e_s _o_f _I_E_E_E _s_t_a_n_d_a_r_d_i_z_a_t_i_o_n _a_c_t_i_v_i_t_i_e_s. _P_e_r_m_i_s_s_i_o_n _i_s _a_l_s_o _g_r_a_n_t_e_d _f_o_r _m_e_m_b_e_r _b_o_d_i_e_s _a_n_d _t_e_c_h_n_i_c_a_l _c_o_m_m_i_t_t_e_e_s _o_f _I_S_O _a_n_d _I_E_C _t_o _r_e_p_r_o_d_u_c_e _t_h_i_s _d_o_c_u_m_e_n_t _f_o_r _p_u_r_p_o_s_e_s _o_f _d_e_v_e_l_o_p_i_n_g _a _n_a_t_i_o_n_a_l _p_o_s_i_t_i_o_n. _O_t_h_e_r _e_n_t_i_t_i_e_s _s_e_e_k_i_n_g _p_e_r_m_i_s_s_i_o_n _t_o _r_e_p_r_o_d_u_c_e _t_h_i_s _d_o_c_u_m_e_n_t _f_o_r _s_t_a_n_d_a_r_d_i_z_a_t_i_o_n _o_r _o_t_h_e_r _a_c_t_i_v_i_t_i_e_s, _o_r _t_o _r_e_p_r_o_d_u_c_e _p_o_r_t_i_o_n_s _o_f _t_h_i_s _d_o_c_u_m_e_n_t _f_o_r _t_h_e_s_e _o_r _o_t_h_e_r _u_s_e_s, _m_u_s_t _c_o_n_t_a_c_t _t_h_e _I_E_E_E _S_t_a_n_d_a_r_d_s _D_e_p_a_r_t_m_e_n_t _f_o_r _t_h_e _a_p_p_r_o_p_r_i_a_t_e _l_i_c_e_n_s_e. _U_s_e _o_f _i_n_f_o_r_m_a_t_i_o_n _c_o_n_t_a_i_n_e_d _i_n _t_h_i_s _u_n_a_p_p_r_o_v_e_d _d_r_a_f_t _i_s _a_t _y_o_u_r _o_w_n _r_i_s_k. IEEE Standards Department Copyright and Permissions 445 Hoes Lane, P.O. Box 1331 Piscataway, NJ 08855-1331, USA +1 (908) 562-3800 +1 (908) 562-1571 [FAX] _S_e_p_t_e_m_b_e_r _1_9_9_1 _S_H _X_X_X_X_X BEGIN_RATIONALE _E_d_i_t_o_r'_s _N_o_t_e_s This section will not appear in the final document. It is used for editorial comments concerning this draft. Comments in italics are not intended to form part of the final guide; they are editor's or coordinator comments for the benefit of reviewers. This draft uses small numbers in the right margin in lieu of change bars. d ``D'' denotes changes from Draft 12 to Draft 13. Per request of the d working group, I have removed all old diff-marks from Drafts 3 through d 12. Purely editorial changes such as grammar, spelling, cross references, or removals of editorial notes are not diff-marked. Unfortunately, it is not possible to accurately diff-mark the figures. To make draft handling in the meetings easier, each significant clause is set up to print starting on a recto page. This means that there is a larger number of blank pages than in previous drafts (assuming that the copy room handled the print master correctly). Just doing our bit for deforestation ... This draft has not yet been converted to use proper normative reference d and bibliographic entries and cross references. Since this will entail a d large amount of detailed work, I have been awaiting some degree of text d stability. For Draft 13, three major sections were replaced in their d entirety (and, interestingly enough, all three were received d approximately one month after the input cutoff date), so I believe the d required stability has not yet been achieved. d Hal Jespersen d Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. _E_d_i_t_o_r_i_a_l _C_o_n_t_a_c_t_s Please send comments regarding the content and approach of this document to: Fritz Schulz Open Software Foundation 620 Herndon Parkway - Suite 200 Herndon, VA 22070 +1 (703) 481-9851 FAX: +1 (703) 437-0680 E-Mail: fschulz@osf.ORG Please report typographical errors (and index suggestions) to: Hal Jespersen POSIX Software Group 447 Lakeview Way Redwood City, CA 94062 +1 (415) 364-3410 FAX: +1 (415) 364-4498 E-Mail: hlj@Posix.COM (Electronic mail is preferred.) Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. _O_n_l_i_n_e _A_c_c_e_s_s d This draft is available in various electronic forms to assist the review d process. Our thanks to Andrew Hume of AT&T Bell Laboratories for d providing online access facilities. Note that this is a limited d experiment in providing online access; future drafts may be provided in d other forms, such as diskettes or a bulletin board arrangement, but the d instructions shown here are the only methods currently available. Please d also observe the additional copyright restrictions that are described in d the online files. d Assuming you have access to the Internet, the scenario is approximately d ftp research.att.com # research's IP address is 192.20.225.2 d <login as netlib; password is your email address> d cd posix/p1003.0/d13 d get toc index d binary d get p11-20.Z d The draft is available in several forms. The table of contents can be d found in toc, pages containing a particular section are stored under the d section number, sets of pages are stored in files with names of the form d p_n-_m, and the entire draft is stored in all. By default, files are d ASCII. A .ps suffix indicates PostScript. A .Z suffix indicates a d compress'_e_d file. The file index contains a general description of the d files available. d These files are also available via electronic mail by sending a message d like d send 3.4 4.6 6.2 from posix/p1003.0/d13 d to netlib@research.att.com. If you use email, you should _n_o_t ask for the d compressed version. For a more complete introduction to this form of d _n_e_t_l_i_b, send the message d send help d Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. _P_O_S_I_X._0 _C_h_a_n_g_e _H_i_s_t_o_r_y This section is provided to track major changes between drafts. Since it was first added in Draft 10, earlier entries have been omitted. Draft 13 [September 1991] d - _T_o _B_e _P_r_o_v_i_d_e_d d Draft 12 [June 1991] - Clause 4.9: Separated OLTP model discussion into d two parts: the part consistent with the POSIX OSE d Model; and the ``real world'' part dealing with d System Integration Interfaces. d - Section 6: Further clarified ``base standard'' and d ``profile'' definitions. Renamed profile ``types''. d - _A_d_d_i_t_i_o_n_a_l _T_o _B_e _P_r_o_v_i_d_e_d d Draft 11 [March 1991] - _T_o _B_e _P_r_o_v_i_d_e_d _H_L_J: _I _d_o_n'_t _d_o _t_h_i_s _a_u_t_o_m_a_t_i_c_a_l_l_y _b_e_c_a_u_s_e _I _d_o_n'_t _k_n_o_w _w_h_a_t _i_s_s_u_e_s _y_o_u _c_o_n_s_i_d_e_r _i_m_p_o_r_t_a_n_t. _T_h_i_s [_v_e_r_y _b_r_i_e_f] _t_e_x_t _s_h_o_u_l_d _b_e _p_r_o_v_i_d_e_d _b_y _e_a_c_h _S_e_c_t_i_o_n _L_e_a_d_e_r _a_l_o_n_g _w_i_t_h _t_h_e _r_e_g_u_l_a_r _s_u_b_m_i_s_s_i_o_n_s. _I_t _i_s _m_e_a_n_t _t_o _p_r_o_v_i_d_e _c_a_s_u_a_l _r_e_a_d_e_r_s _o_f _t_h_e _g_u_i_d_e (_s_u_c_h _a_s _i_n _W_G_1_5, _w_h_e_r_e _t_h_e_y _d_o_n'_t _g_e_t _e_v_e_r_y _d_r_a_f_t) _w_i_t_h _a _b_r_o_a_d _o_v_e_r_v_i_e_w _o_f _t_h_e _b_i_g _c_h_a_n_g_e_s. Draft 10 [December 1990] - _T_o _B_e _P_r_o_v_i_d_e_d END_RATIONALE Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. IEEE Standards documents are developed within the Technical Committees of the IEEE Societies and the Standards Coordinating Committees of the IEEE Standards Board. Members of the committees serve voluntarily and without compensation. They are not necessarily members of the Institute. The standards developed within IEEE represent a consensus of the broad expertise on the subject within the Institute as well as those activities outside of IEEE that have expressed an interest in participating in the development of the standard. Use of an IEEE Standard is wholly voluntary. The existence of an IEEE Standard does not imply that there are no other ways to produce, test, measure, purchase, market, or provide other goods and services related to the scope of the IEEE Standard. Furthermore, the viewpoint expressed at the time a standard is approved and issued is subject to change brought about through developments in the state of the art and comments received from users of the standard. Every IEEE Standard is subjected to review at least every five years for revision or reaffirmation. When a document is more than five years old and has not been reaffirmed, it is reasonable to conclude that its contents, although still of some value, do not wholly reflect the present state of the art. Users are cautioned to check to determine that they have the latest edition of any IEEE Standard. Comments for revision of IEEE Standards are welcome from any interested party, regardless of membership affiliation with IEEE. Suggestions for changes in documents should be in the form of a proposed change of text, together with appropriate supporting comments. Interpretations: Occasionally questions may arise regarding the meaning of portions of standards as they relate to specific applications. When the need for interpretations is brought to the attention of the IEEE, the Institute will initiate action to prepare appropriate responses. Since IEEE Standards represent a consensus of all concerned interests, it is important to ensure that any interpretation has also received the concurrence of a balance of interests. For this reason, the IEEE and the members of its technical committees are not able to provide an instant response to interpretation requests except in those cases where the matter has previously received formal consideration. Comments on standards and requests for interpretations should be addressed to: Secretary, IEEE Standards Board 445 Hoes Lane P.O. Box 1331 Piscataway, NJ 08855-1331 Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. __________________________________________________________________ |IEEE Standards documents are adopted by the Institute of | |Electrical and Electronics Engineers without regard | |to whether their adoption may involve patents | |on articles, materials, or processes. | |Such adoption does not assume any liability to any patent owner, | |nor does it assume any obligation whatever to parties adopting | _||t_h_e__s_t_a_n_d_a_r_d_s__d_o_c_u_m_e_n_t_s_.__________________________________________|| Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. Contents PAGE Introduction........................................................ ii Purpose.......................................................... ii The POSIX Open System Environment Reference Model................ ii Goals............................................................ ii Benefits......................................................... ii Related Standards Activities..................................... ii Section 1: General.................................................. 1 1.1 Scope...................................................... 1 1.2 Normative References....................................... 2 1.3 Conformance................................................ 3 Section 2: Terminology and General Requirements..................... 5 2.1 Conventions................................................ 5 2.2 Definitions................................................ 5 2.2.1 Terminology......................................... 5 2.2.2 General Terms....................................... 7 2.2.3 Abbreviations....................................... 13 Section 3: POSIX Open System Environment............................ 15 3.1 POSIX Open System Environment - General Requirements....... 16 3.2 POSIX Open System Environment Reference Model.............. 19 3.3 POSIX Open System Environment Services..................... 28 3.4 POSIX Open System Environment Standards.................... 29 3.5 POSIX Open System Environment Profiles..................... 32 3.6 Application Platform Implementation Considerations......... 33 Section 4: POSIX Open System Environment Services................... 39 4.1 Language Services.......................................... 43 4.2 System Services............................................ 53 4.3 Network Services........................................... 77 4.4 Database Services.......................................... 103 4.5 Data Interchange Services.................................. 117 4.6 Windowing System Services.................................. 125 4.7 Graphics Services.......................................... 145 4.8 Character-Based User Interface Services.................... 167 4.9 User Command Interface Services............................ 173 4.10 Transaction Processing Services............................ 183 4.11 Software Development Environments.......................... 197 Section 5: POSIX OSE Cross-Category Services........................ 207 5.1 Internationalization....................................... 209 Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. ii PAGE 5.2 System Security Services................................... 229 5.3 Information System Management.............................. 235 5.4 Fault Management........................................... 245 Section 6: Profiles................................................. 249 6.1 Scope...................................................... 249 6.2 Profile Concepts........................................... 250 6.3 Guidance to Profile Writers................................ 252 Section 7: POSIX SP Profiling Efforts............................... 261 7.1 Introduction............................................... 261 7.2 General Purpose POSIX SPs.................................. 261 Annex A (informative) Considerations for Developers of POSIX SPs.... 273 A.1 Introduction............................................... 273 A.2 Scope...................................................... 273 A.3 The Role of POSIX SPs...................................... 274 A.4 Special Rules for POSIX SPs................................ 275 A.5 Other Issues............................................... 277 A.6 Conformance to a POSIX SP.................................. 279 A.7 Structure of Documentation for POSIX SPs................... 279 A.8 Rules for Drafting and Presentation of POSIX SPs........... 281 Annex B (informative) Bibliography.................................. 287 Annex C (informative) Standards Infrastructure Description.......... 289 C.1 Introduction............................................... 289 C.2 The Formal Standards Groups................................ 291 C.3 The Informal Standards Organizations....................... 306 Annex D (informative) Electronic-Mail............................... 321 Alphabetic Topical Index............................................ 323 FIGURES Figure 3-1 - POSIX OSE Reference Model............................ 20 Figure 3-2 - POSIX OSE Reference Model - Entities................. 22 Figure 3-3 - POSIX OSE Reference Model - Interfaces............... 24 Figure 3-4 - POSIX OSE Reference Model - Distributed Systems...... 28 Figure 3-5 - Distributed System Environment Model................. 29 Figure 3-6 - Service Components and Interfaces.................... 33 Figure 3-7 - Application Platform Implementation - Subdivision.... 35 Figure 3-8 - Application Platform Decomposition II - Layering..... 36 Figure 3-9 - Application Platform Decomposition III - Redirection...................................................... 36 Figure 4-1 - Language Service Reference Model..................... 44 Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. iii Figure 4-2 - System Services Reference Model...................... 54 Figure 4-3 - Realtime Metrics..................................... 57 Figure 4-4 - POSIX Networking Reference Model..................... 78 Figure 4-5 - ISO Networking Reference Model....................... 81 Figure 4-6 - Relationship of ISO and POSIX OSE Network Reference Models........................................................... 83 Figure 4-7 - Multiple POSIX OSE APIs to Different OSI Layers...... 84 Figure 4-8 - Basic Network Services Model......................... 85 Figure 4-9 - Directory Services Architecture...................... 87 Figure 4-10 - OSI Network Services Standards...................... 101 Figure 4-11 - The Traditional Database Model...................... 105 Figure 4-12 - POSIX Database Reference Model...................... 106 Figure 4-13 - Data Interchange Reference Model.................... 118 Figure 4-14 - Windowing Reference Model........................... 127 Figure 4-15 - Computer Graphics Reference Model Level Structure... 149 Figure 4-16 - POSIX OSE Graphics Service Reference Model.......... 150 Figure 4-17 - POSIX OSE Graphics Service Reference Model Standards........................................................ 156 Figure 4-18 - Character-based Terminal Reference Model............ 168 Figure 4-19 - POSIX OSE Reference Model for Command Interfaces.... 174 Figure 4-20 - The Conventional Transaction Processing Model....... 186 Figure 4-21 - The POSIX OSE Transaction Processing Reference Model............................................................ 187 Figure 4-22 - Software Development Model.......................... 199 Figure 4-23 - Software Development Reference Model................ 200 Figure 6-1 - Development of a Profile............................. 258 Figure A-1 - Universe of Profiles and Standards................... 274 Figure C-1 - International and National Standards Bodies.......... 291 Figure C-2 - Selected Major Standards and Standards-Influencing Bodies........................................................... 292 Figure C-3 - IEEE Standards Diagram............................... 302 TABLES Table 4-1 - Language Standards Activities......................... 49 Table 4-2 - System Services Standards Activities.................. 67 Table 4-3 - Functionality of POSIX.1 Standard..................... 69 Table 4-4 - Current Networking Standards.......................... 98 Table 4-5 - Emerging Networking Standards......................... 99 Table 4-6 - Gaps in Networking Standards.......................... 100 Table 4-7 - Database Standards.................................... 111 Table 4-8 - Data Interchange Standards............................ 121 Table 4-9 - Windowing Standards................................... 140 Table 4-10 - Shell and Utilities Standards Activities............. 179 Table 4-11 - Transaction Processing Standards Activities.......... 192 Table 4-12 - Transaction Processing Standards Language Bindings... 193 Table 4-13 - Software Development Standards Activities............ 202 Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. iv Table 7-1 - POSIX SPs In Progress................................. 262 Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. v Introduction (This Introduction is not a normative part of P1003.0 Guide to the POSIX Open Systems Environment, but is included for information only.) Purpose There are many standards efforts going on throughout the world today. Standards are being developed in many areas of computing technology such as: - Electrical Connectors - Disk Interfaces - Network Interfaces - Application Program Interfaces Each standards effort typically addresses a very small portion of the overall needs of an information processing system. This guide is an attempt bring together many different standards sufficient to address the scope of an entire information processing system. This combination of standards and specifications that are sufficient to address all of the user requirements of an information processing system is called an Open System Environment. User requirements and standards to meet those requirements are continuously expanding. As such, this guide will need regular revision to incorporate new user requirements and the new standards that evolve to meet those user requirements. This guide is not a standard itself; it merely identifies standards that can be used when constructing a complete information processing system. It may never be necessary to implement an information processing system that provides every standard in the POSIX Open System Environment. Typically a subset of the standards is sufficient to satisfy the particular user requirements in each situation. This process of selecting standards for a particular application is called profiling. Recommendations for the production of different types of profiles are included in the guide. Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. vi Introduction This guide is intended to be used by any computer user interested in using standards in their information processing systems including: consumers, systems integrators, application developers, systems providers, and procurement agencies. Taken as a whole, the guide maps existing and emerging standards onto the general requirements of a complete information processing system. In addition to listing and categorizing existing standards efforts, the guide identifies important requirements that standards efforts have not yet addressed. The POSIX Open System Environment Reference Model To describe the POSIX Open System Environment, the guide develops a reference model used to classify information processing standards. The reference model breaks standards into three general categories: - Platform External Interface Standards--These standards affect how an information processing system interacts with its external environment. These standards affect system interoperability, user interface look and feel, and data portability. - Application Program Interface Standards--These standards affect how application software interacts with the computer system. These standards affect application portability. - System Integration Interface Standards--These interfaces have no direct impact on the external interface of a system or the application program interface to the system. These interfaces are between the various parts of an information processing system. These standards are very important because they allow a user to independently procure portions of their information processing systems from multiple vendors according to each user's needs. The information processing system is broken into major component areas. Using the reference model, a general set of requirements for each component area is developed. For each of the requirements existing or emerging standards are identified that address the requirement. If a requirement is not completely met by an existing or emerging standard, this gap in the standards is noted. Goals There are three goals of the POSIX OSE: portability, interoperability, and user portability. (While these terms are formally defined later in this guide and within various referenced standards, the following descriptions provide an overview of their meaning.) Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. Goals vii Portability Portability is accomplished through the use of the respective system/application interface standards and their extensions, thus allowing a user's application to operate on a wide range of systems. It is important to note that the aforementioned phrase ``wide range of systems'' connotes diverse hardware as well as software platforms. Using standards to provide application portability also will allow an application to be moved to systems with varying compute capabilities based on the performance needs of the application. Interoperability Interoperability is characterized by the cooperative operation of applications resident on dissimilar computer systems. This cooperative operation is illustrated by data and functionality exchange. User Portability User portability will allow users to move from system to system and between different applications on the same system with a minimum of retraining. Benefits The benefits derived in the use of the POSIX Open System Environment are real and quantifiable. Simplified Vendor Mixing System Integration As the standards for system integration and system interoperability are produced and implemented, the users will have the choice of mixing software and equipment from multiple vendors. This will allow users to tailor their information processing system to their particular needs by selecting their hardware based on the application needs rather than its ability to interoperate with their existing equipment. Efficient Development and Implementation Normally, systems users and providers have development and implementation activities that utilize personnel possessing skills in a specific computer environment. As a result of this specialization, a change in the target computer environment for a developer requires significant retraining expense. As standards for application portability, system interoperability, Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. viii Introduction and system integration are developed, computer personnel will begin to develop skills in working with these standards. When these standards are widely used there will be large pool of personnel who are familiar with working with the standards. This will allow a company to hire personnel with existing skills which can be put to use in their operation. In addition, within a company, resources can be redeployed between development efforts with a minimum of retraining. As the basic interfaces are developed and well defined, higher level standardized interfaces can be developed that add value to the basic interfaces. Using the higher level interfaces may speed development efforts. Efficient Porting of Applications The difficulty of moving an application from one hardware/software environment to another is widely known. The porting of an application that uses standards-based interfaces to another system that provides the same standards-based interfaces is considerably simpler than ports involving completely different systems. The amount of system tailoring (i.e., changes to either the operating or application system required to make them work well together) is greatly reduced. Broadened Basis for Computer System Procurement Decisions Computer users can now select and match hardware and software components from potentially different suppliers to fulfill an application requirement. This in turn allows decisions regarding computer systems procurements to be based less upon constraints imposed by incumbent vendors' products. The basis for competition will refocus on such factors as price, quality, value-added features, performance, and support. The stimulation of competition will benefit providers and users. Reduced Personnel Training Both providers and users of computer systems face high training costs when they switch hardware/software environments within which their application exists. Usage of standards makes inroads into reducing the costs of retraining users of all types. Reduced training will be incurred for developers and end-users alike. Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. Benefits ix Related Standards Activities The Standards Subcommittee of the IEEE Technical Committee on Operating Systems and Application Environments has authorized other standards activities that are related to the content of this guide. The following areas are under active consideration at this time, or are expected to become active in the near future:1) (1) Language-independent service descriptions of the POSIX.1 {2} system application program interface (API) (2) C, Ada, and FORTRAN Language bindings to (1) (3) Shell and Utility facilities (4) Verification testing methods (5) Realtime facilities (6) Secure/Trusted System considerations (7) Network interface facilities (8) System Administration (9) Graphical User Interfaces (10) Profiles describing application- or user-specific combinations of Open Systems standards for: supercomputing, multiprocessor, and batch extensions; transaction processing; realtime systems; and multiuser systems based on historical models Extensions are approved as ``amendments'' or ``revisions'' to this document, following the IEEE and ISO/IEC Procedures. Approved amendments are published separately until the full document is reprinted and such amendments are incorporated in their proper positions. __________ 1) A _S_t_a_n_d_a_r_d_s _S_t_a_t_u_s _R_e_p_o_r_t that lists all current IEEE Computer Society standards projects is available from the IEEE Computer Society, 1730 Massachusetts Avenue NW, Washington, DC 20036-1903; Telephone: +1 202 371-0101; FAX: +1 202 728-9614. Working drafts of POSIX standards under development are also available from this office. Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. x Introduction If you have interest in participating in the TCOS working groups addressing these issues, please send your name, address, and phone number to the Secretary, IEEE Standards Board, Institute of Electrical and Electronics Engineers, Inc., P.O. Box 1331, 445 Hoes Lane, Piscataway, NJ 08855-1331, and ask to have this forwarded to the chairperson of the appropriate TCOS working group. If you have interest in participating in this work at the international level, contact your ISO/IEC national body. P1003.0 was prepared by the 1003.0 working group, sponsored by the Technical Committee on Operating Systems and Application Environments of the IEEE Computer Society. At the time this standard was approved, the membership of the 1003.0 working group was as follows: Technical Committee on Operating Systems and Application Environments (TCOS) Chair: Jehan-Franc,ois Pa^ris TCOS Standards Subcommittee Chair: Jim Isaak Vice Chairs: Ralph Barker Robert Bismuth Hal Jespersen Lorraine Kevra Pete Meier Treasurer: Quin Hahn Secretary: Shane McCarron 1003.0 Working Group Officials Chair: Allen Hankinson Vice Chair: Kevin Lewis Document Editor: Hal Jespersen (sponsored by Mike Lambert) Technical Editor: Fritz Schulz Secretary: Charles Severance Working Group <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. xi The following persons were members of the 1003.0 Balloting Group that approved the standard for submission to the IEEE Standards Board: <_N_a_m_e> <_I_n_s_t_i_t_u_t_i_o_n> _I_n_s_t_i_t_u_t_i_o_n_a_l _R_e_p_r_e_s_e_n_t_a_t_i_v_e <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> <_N_a_m_e _t_o _b_e _p_r_o_v_i_d_e_d> When the IEEE Standards Board approved this standard on <_d_a_t_e _t_o _b_e _p_r_o_v_i_d_e_d>, it had the following membership: (to be pasted in by IEEE) Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. xii Introduction P1003.0/D13 Guide to the POSIX Open Systems Environment Section 1: General _R_e_s_p_o_n_s_i_b_i_l_i_t_y: _K_e_v_i_n _L_e_w_i_s 1.1 Scope This guide identifies parameters for an open system environment using the POSIX operating system/application interface as the platform. These parameters are determined in three basic ways: (1) By specifying building blocks identified as components Currently these components are: system services, networking, human/computer interaction (HCI), graphics, system security and privacy, database, data interchange, and language requirements. This guide identifies the standards required within each component to achieve the goals of a POSIX open system. (2) By identifying intra- and intercomponent issues These issues involve the relationships that should exist between and among the different components. It is in the attempt to lay out and address these relationships that the concept of profiles (see 2.2.2 and Section 6) arises. Copyright c 1991 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft, subject to change. 1.1 Scope 1