Open System Handbook: A Guide to Building Open Systems


Published by Digital Equipment Corporation, USA


This book is designed to provide interested individuals and organizations with an overview of open systems and the work being done to achieve them. Its focus is on the information and processes that open systems architects and planners may use to make strategic decisions about open systems in their organizations.

An open systems environment potentially provides benefits for users, software developers, and system suppliers in ways specific to each group's interests. For users, part of the promise of open systems is in investment protection provided by the ability to adapt and evolve systems and solutions as needs and technologies change. Open systems also promise significant savings and a competitive advantage for companies that can apply them effectively.

In order to realize the promise of open systems, those responsible for an organization's information technology systems must understand the underlying concept of open systems and apply it to their business in an appropriate way. In addition, technology planners and implementors need to recognize that there is no single answer that will deliver the benefits of open systems to all users in all situations. Nor are off-the-shelf solutions available for all open systems needs. To successfully apply open systems technology as a competitive advantage, companies must be knowledgeable about what open systems can or cannot do for any particular business situation.

The focus on open systems today is concentrated not only on operating systems, but also on standardizing interfaces to link existing systems, applications, and users. The interface approach concentrates on getting internationally accepted industry standards in place and on adding a variety of components to a common, modular operating environment. It is believed that the implementation of standards on each system within a network will provide a common and uniform structure that will reduce difficulties in bridging heterogeneous systems.

In addition, the interface standards approach to open systems gives the user an extra margin of safety because products that do implement specifications and standards are conformant and can be tested and verified as such. In the open systems arena, conformance is a real source of vendor independence for the user.

Ultimately, an open system, however it is defined, must meet the users' objectives. The central question that users must always ask themselves is:

"Does this product provide sufficient functionality for my open systems needs?" Following a well-designed, focused plan for developing a computing

environment is the best way to ensure that this question is answered properly. Defining such a plan requires identifying goals and priorities and carefully examining how each element of the environment matches those objectives.

Section I of this book presents conceptual and background information about open systems, the open systems arena, and ways in which companies and organizations can most effectively address open systems issues.

Section II of this handbook includes information on the current status of internationally accepted industry standards and specifications for open systems. This section is organized using a descriptive model of an open systems environment developed by the Central Computer and Telecommunications Agency (CCTA), the United Kingdom's procurement agency. The model, based on the acronym MUSIC, includes elements for management (M), user interface (U), system services (S), information and data (I), and communications(C). In addition. Chapter 11 deals with several issues that transcend these categories including security, internationalization, and software development environments.

Appendices include an overview guide to standards developing organizations and consortia, a listing of standards development organizations, and a summary of open systems environments developed by prominent standards and open systems organizations.


Section I Open Systems Explored

Chapter 1 Introduction

Chapter 2 Open Systems: Concept and Reality

The Evolution of Open Systems   2-1
Definition of an Open System   2-4
Perceptions of "Open"    2-5
    Standard Platforms   2-6
    Networking   2-6
    Availability and Accessibility  2-7
Relating Definitions of Open Systems   2-8
Open Systems Potential  2-9
Standards for Open Systems  2-10

Chapter 3 The Open Systems Environment

Organizing the Discussion  3-1
Elements and Components of MUSIC  3-2
Other Services   3-4
Aligning Products and Standards with the MUSIC Model   3-5

Chapter 4 Application Environment Profiles

Profile Development Within Standards Organizations  4-5

Chapter 5 Applying Open Systems Information to Your Business

Steps to Implement an Open Systems Environment  5-1
    Step 1: Know your business objectives  5-1
    Step 2: Identify application requirements   5-2
    Step 3: Prepare a profile that identifies the suite of capabilities
needed to support your application  5-2 
    Step 4: Acquire or engineer software that matches your
profile  5-2
    Step 5: Verify the open systems characteristics of the application  5-3
    Step 6: Verify that business objectives are met  5-3
    Step 7: Repeat the sequence  5-4
    Human Factors  5-4 
Using Standards in Describing Applications   5-4
    Profile Development 5-5
    Levels of Conformance 5-7
    Managing Software Development 5-9
    Conformance Testing of Applications 5-9 
Using Standards in Buying Systems 5-10

Section II Elements of an Open System

Chapter 6 The Management Element

The Management Element  6-1
Description of Current Standards Work  6-1
History and Current Status  6-2
    ISO/IEC Management Standards Activities  6-2
    TCP/IP Management Activities  6-4
        RFC 1157 Simple Network Management Protocol (SNMP)  6-4
        Coexistence of TCP/IP and OSI 6-5   
    IEEE POSIX 1003.7 System Administration  6-5
    Open Software Foundation's Distributed Management  
        Environment 6-6
        User Interface  6-7
        Management Applications 6-7
        Common Management Services 6-7
        Managed Objects 6-7

Chapter 7 The User Interface Element

POSIX 1003.2: The Shell and Utilities Working Group  7-2
    Description of POSIX 1003.2 standards  7-2
        POSIX 1003.2a: User Portability Extension  7-4
Form Interface Management System (FIMS)  7-4
    Description  7-4
    History and Status  7-5
X Window System 7-6
    Description  7-6
    History and Status 7-8
Graphical User Interfaces 7-8
    OSF/Motif  7-8
    Open Look  7-9

Chapter 8 The System Services Element

Languages  8-1
Portable Operating System Interface (POSIX)  8-4
    Description 8-5
    History and Current Status  8-8
    POSIX-related International Work 8-9
Graphics 8-10
    GKS  8-10
        History and Current Status 8-10
    GKS-3D  8-11
    PHIGS  8-11
        Description  8-11
        History and Current Status  8-12
    PEX  8-13

Chapter 9 The Information and Data Services Element

Data Definition and Access  9-1
    Database Language Standards  9-1
        The SQL Standard  9-2
        Network Database Language  9-3
    Remote Database Access  9-3
        Description  9-4
        History and Status  9-4
    Data Repository and Management Systems 9-5
        IRDS Description  9-5
        History and Status  9-5
I    ndexed Sequential Access Method (ISAM)  9-6
Document Data Interchange and Processing  9-7
    The Office Document Architecture (ODA) and Office Document Interchange Format (ODIF)  9-7 
        Description  9-7
        History and Status  9-8
        Standard Generalized Markup Language (SGML) and Standard Document Interchange Format (SDIF)   9-9
        Electronic Data Interchange (EDI)   9-10
        Initial Graphics Exchange Specification (IGES)  9-10
        Electronic Design Interchange Format (EDIF)  9-11
    PDES/STEP   9-11
        Description  9-11
        History and Status  9-12

Chapter 10 The Communications Services Element

The Internet Protocol (TCP/IP)  10-1
    Description  10-1
    History and Status 10-3
Open Systems Interconnection (OSI) 10-5
    OSI Base Standard Description  10-5
    History and Current Status  10-6
        Functional Standards: International Standardi2ed Profiles 10-8
        OSI-related Profile Work  10-9
        Testing  10-11
Selected Established or Emerging Communications Standards   10-12
    ISO/CCITT X.400, Mail and Message Interchange  10-12
    ISO/CCITT X.500, Directory Services  10-12
    File Transfer Access and Management (FTAM)  10-12
    Remote Procedure Calls  10-13
    ISO/CCITT X.25 (WAN standard)  10-13
    Local Area Network (LAN) Standards  10-14
        IEEE 802.3 Standard for Ethernet Technology  10-14
        Token RingIEEE 802.5  10.14
        Fiber Distributed Data Interface  10-15

Chapter 11 Other Concerns

Security  11-1
    Communications Security  11-2
        Operating System Security  11-2
Internationalization  11-4
Software Development Environment  11-7
    PCTE  11-7
    A Tools Integration Standard (ATIS)  11-8
    CASE Integration Services 11-8

Appendix A Overview Guide to Standards Developing Organizations and Consortia

Appendix B Standards Development Organizations

Appendix C Open Systems Environments

Appendix D Bibliography

Appendix E Glossary of Open Systems Environment/Standards-related Terms


2-1 Open Systems Potential  2-9
3-1 MUSIC Framework for Open Systems 3-2
3-2 The MUSIC Model 3-5
4-1 Open Systems Profile Components  4-2
4-2 The Role of Application Environment Profiles in Open
Systems Implementation  4-4
4-3 Organization Levels for Profile Development  4-8
5-1 Commercial Accounting Application  5-6
5-2 Engineering CAD/CAM Application 5-6
5-3 POSIX Conformance Levels for Applications 5-8
5-4 Added Value in Open Systems  5-10
6-1 Distributed Management Environment Model  6-6
7-1 POSIX 1003.2 Components  7-3
7-2 X Window System  7-7
10-1 OSI Reference Model  10-6
11-1 International Product Model  11-5
11-2 International Software Model  11-6
A-1 Standards Developing Organizations and Consortia   A-1
A-2 European Regional Standards Structure    A-2
C-1 Open Systems Environment Components   C-1
C-2 IEEE TCOS Standards Work   C-2
C-3 NIST Applications Portability Profile   C-3
C-4 European Commission Guidelines for an Informatics Architecture (1990)  C-4
C-5 X/Open Common Applications Environment C-5
C-6 Open Software Foundation Applications Environment Specification (AES)  C-6


8-1 Internationally Standardized Languages  8-3
8-2 Language Bindings for Commonly Implemented ISO
Standards   8-4
10-1 IAB Network-Specific Standard Protocols  10-4
10-2 ISO/IEC JTC1 Subcommittees and Working Groups with Particular Emphasis on OSI and OSI-related Standards
10-2 ISO/IEC JTC1 Subcommittees and Working Groups with Particular Emphasis on OSI and OSI-related Standards               (Continued)  10-8
11-1 TCSEC Operating-System Security Levels  11-3