1、INTERNATIONAL STANDARD ISO/IEC 10027 First edition 1990-06-15 Information technology - Information Resource Dictionary System (IFIDS) framework Technologies de Iinformation - Cadre pour le gestionnaire de ressources du syst b) the computerized and possibly non- computerized processes which are avail
2、able for presenting and maintaining such data; c) the available physical hardware environment on which such data can be represented; (9 the organization of human and physical resources which can make use of the information; e) the human resources responsible for generating that information. An Infor
3、mation Resource Dictionary System (IRDS) is a system which provides facilities for creating, maintaining and accessing an Information Resource Dictionary (IRD) and its IRD definition. It must be emphasized that this family of International Standards does not provide a standard definition for all of
4、the above kinds of information. It does provide a framework for defining such information and in which the information can be represented and managed. The definition of those kinds of information to be represented in an Information Resource Dictionary, that are suitable for standardisation, are a su
5、bject for other International Standards in this family. The content of an Information Resource Dictionary can be compared with the content of a typical application database. An application database contains data of relevance to the day to day operation of an enterprise. Such data may refer to things
6、 such as employees, suppliers, customers and purchase orders. The data in an Information Resource Dictionary is in many ways similar to that in an application database, but it is on a higher level. Such data may refer to things such as data item types, data files, computer programs and sub-systems.
7、5.2 The IRDS family of Standards This International Standard for an IRDS Framework specifies the overall architecture in which each member of the IRDS family of International Standards should be positioned. The Framework identifies, in general terms, the kinds of data together with the major process
8、ors and their 00 a Figure 2 - Icon for a person 4.4 Storage medium A storage medium is a device on which data of any kind may be recorded such as a hard disc, a floppy disc or tape. A storage medium is represented by the icon shown in figure 3. Data will be held on some storage medium. The name with
9、in the icon identifies the content of the storage medium. PI Name Figure 3 - Icon for a storage medium 4.5 Client - Server association Users of services provided at an interface are termed clients. The processor that provides the services at an interface is termed the server. A processor may fill th
10、e role of client and the role of server. A processor can be the server to one interface. A processor may be a client of many interfaces. A client may be a person or a processor depending upon the nature of the interface. Use of an interface by a client is shown by a line connecting them. Use of a st
11、orage medium by a processor is shown by a line between them as illustrated in figure 4. Figure 4 - Conventions to show Client - Server associations 4.6 Diagramming conventions All figures using the conventions described above are drawn so that the client is shown to the left of the server. This conv
12、ention is illustrated in figure 4. 3 ISO/IEC 10027 : 1990 (E) associated interfaces and the broad nature of the services provided at each interface. Some, but not all, of the interfaces identified in this International Standard are candidates for standardisation as members of the IBDS family of Inte
13、rnational Standards. More than one standard may be developed for a given interface. Two International Standards for the same interface may differ according to any mix of the following i3SpXt.9: 4 b) d (9 Programming language dependence; Interface style; Data modelling facility used Data interchange
14、format. Each aspect will be considered in turn. 5.2.1 Programming language dependence Numerous programming language dependencies are possible and there exist many International Standards for programming languages. 5.2.2 Interface styles 5.2.2.1 Interface styles for processors Possible alternative in
15、terface styles which may be used by processors are the following: a) b) d Programmatic - procedure call; Syntax (execution time interpretation); Service conventions (as used with OS1 services). A procedure call interface defines a sequenced set of parameters and the associated binding rules for the
16、CALL statement of an International Standard programming language. A procedure call may also be implicit which means that a statement is used which is translated into a CALL statement prior to compilation. A syntax for execution time interpretation is similar to that provided for a human user with th
17、e difference that the linguistic forms are interpreted at execution time by a processor specific to an International Standard programming language. A service convention is a standard set of programming language independent conventions for specifying parameter lists and service primitives for use in
18、an open system environment. 5.2.2.2 Interface styles for persons Possible alternative styles for interfaces to persons are the following: a) Panels (abstract screen formats); b) Concrete syntax; c) Graphics. A panel style of interface defines a grouping of services which may possibly have been defin
19、ed using some other style. A concrete syntax (such as a command language) is the traditional way of defining interfaces for persons. It is important to note that using a syntactic language to define an International Standard does not imply that the same concrete syntax must be used by a person using
20、 the interface. A graphic interface style may be used in conjunction with either a panel interface or with an abstract syntax. 5.2.2.3 Abstract syntax An interface style which can be used to define both interfaces to processors and interfaces to persons is that of an abstract syntax. An abstract syn
21、tax is the specification of a service by using notation rules which are independent of the encoding techniques used to represent them. An abstract syntax emphasises the semantics of the interface and a person may initiate a standard service in a number of different ways such as selecting from a menu
22、, touching a screen or using a special keyboard. Similarly, a processor interface can also be implemented using any one of several interface styles as required. An International Standard using an abstract syntax defines a set of services without prescribing any linguistic form to be used by a person
23、 when each service is initiated or invoked. Such an International Standard also includes the semantics of the services. 5.2.3 Data modelling facility A data modelling facility is a set of rules for defining the structure of data (including constraints) and the semantics of the associated data manipu
24、lation services. Each International Standard for either an interface to a person or an interface serving another processor is dependent on one or more data modelling facilities. Examples of kinds of data modelling facilities include those: a) Based on an International Standard Database Language (suc
25、h as NDL or SQL); b) Based on a non-standard database language; 4 Specific to an International Standard programming language (such as COBOL or PLPI); 9 Specific to a non-language International Standard (such as OS1 Directory Services); 4 Which are non-standard data modelling facilities (such as entity relationship modelling). 4
