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ISEE software Appunti scolastici Premium

Appunti di ingegneria del software della professoressa Fasolino. Il file contiene una lunga trattazione sulla pratica dei requisiti dell'ISEE, il file è interamente in lingua inglese. Inoltre contiene dettagli sulla riduzione dell'effetto di sviluppo.

Esame di Fondamenti di informatica docente Prof. R. Fassolino

Anteprima

ESTRATTO DOCUMENTO

IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

4.3.7 ModiÞable

An SRS is modiÞable if, and only if, its structure and style are such that any changes to the requirements can

be made easily, completely, and consistently while retaining the structure and style. ModiÞability generally

requires an SRS to

a) Have a coherent and easy-to-use organization with a table of contents, an index, and explicit cross-

referencing;

b) Not be redundant (i.e., the same requirement should not appear in more than one place in the SRS);

c) Express each requirement separately, rather than intermixed with other requirements.

Redundancy itself is not an error, but it can easily lead to errors. Redundancy can occasionally help to make

an SRS more readable, but a problem can arise when the redundant document is updated. For instance, a

requirement may be altered in only one of the places where it appears. The SRS then becomes inconsistent.

Whenever redundancy is necessary, the SRS should include explicit cross-references to make it modiÞable.

4.3.8 Traceable

An SRS is traceable if the origin of each of its requirements is clear and if it facilitates the referencing of

each requirement in future development or enhancement documentation. The following two types of trace-

ability are recommended:

a) Backward traceability (i.e., to previous stages of development). This depends upon each requirement

explicitly referencing its source in earlier documents.

b) Forward traceability (i.e., to all documents spawned by the SRS). This depends upon each require-

ment in the SRS having a unique name or reference number.

The forward traceability of the SRS is especially important when the software product enters the operation

and maintenance phase. As code and design documents are modiÞed, it is essential to be able to ascertain the

complete set of requirements that may be affected by those modiÞcations.

4.4 Joint preparation of the SRS

The software development process should begin with supplier and customer agreement on what the

completed software must do. This agreement, in the form of an SRS, should be jointly prepared. This is

important because usually neither the customer nor the supplier is qualiÞed to write a good SRS alone.

a) Customers usually do not understand the software design and development process well enough to

write a usable SRS.

b) Suppliers usually do not understand the customerÕs problem and Þeld of endeavor well enough to

specify requirements for a satisfactory system.

Therefore, the customer and the supplier should work together to produce a well-written and completely

understood SRS.

A special situation exists when a system and its software are both being deÞned concurrently. Then the func-

tionality, interfaces, performance, and other attributes and constraints of the software are not predeÞned, but

rather are jointly deÞned and subject to negotiation and change. This makes it more difÞcult, but no less

important, to meet the characteristics stated in 4.3. In particular, an SRS that does not comply with the

requirements of its parent system speciÞcation is incorrect.

8 Copyright © 1998 IEEE. All rights reserved.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

This recommended practice does not speciÞcally discuss style, language usage, or techniques of good writ-

ing. It is quite important, however, that an SRS be well written. General technical writing books can be used

for guidance.

4.5 SRS evolution

The SRS may need to evolve as the development of the software product progresses. It may be impossible to

specify some details at the time the project is initiated (e.g., it may be impossible to deÞne all of the screen

formats for an interactive program during the requirements phase). Additional changes may ensue as deÞ-

ciencies, shortcomings, and inaccuracies are discovered in the SRS.

Two major considerations in this process are the following:

a) Requirements should be speciÞed as completely and thoroughly as is known at the time, even if

evolutionary revisions can be foreseen as inevitable. The fact that they are incomplete should be

noted.

b) A formal change process should be initiated to identify, control, track, and report projected changes.

Approved changes in requirements should be incorporated in the SRS in such a way as to

1) Provide an accurate and complete audit trail of changes;

2) Permit the review of current and superseded portions of the SRS.

4.6 Prototyping

Prototyping is used frequently during the requirements portion of a project. Many tools exist that allow a

prototype, exhibiting some characteristics of a system, to be created very quickly and easily. See also ASTM

E1340-96.

Prototypes are useful for the following reasons:

a) The customer may be more likely to view the prototype and react to it than to read the SRS and react

to it. Thus, the prototype provides quick feedback.

b) The prototype displays unanticipated aspects of the systems behavior. Thus, it produces not only

answers but also new questions. This helps reach closure on the SRS.

c) An SRS based on a prototype tends to undergo less change during development, thus shortening

development time.

A prototype should be used as a way to elicit software requirements. Some characteristics such as screen or

report formats can be extracted directly from the prototype. Other requirements can be inferred by running

experiments with the prototype.

4.7 Embedding design in the SRS

A requirement speciÞes an externally visible function or attribute of a system. A design describes a particu-

lar subcomponent of a system and/or its interfaces with other subcomponents. The SRS writer(s) should

clearly distinguish between identifying required design constraints and projecting a speciÞc design. Note

that every requirement in the SRS limits design alternatives. This does not mean, though, that every require-

ment is design. 9

Copyright © 1998 IEEE. All rights reserved.

IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

The SRS should specify what functions are to be performed on what data to produce what results at what

location for whom. The SRS should focus on the services to be performed. The SRS should not normally

specify design items such as the following:

a) Partitioning the software into modules;

b) Allocating functions to the modules;

c) Describing the ßow of information or control between modules;

d) Choosing data structures.

4.7.1 Necessary design requirements

In special cases some requirements may severely restrict the design. For example, security or safety require-

ments may reßect directly into design such as the need to

a) Keep certain functions in separate modules;

b) Permit only limited communication between some areas of the program;

c) Check data integrity for critical variables.

Examples of valid design constraints are physical requirements, performance requirements, software devel-

opment standards, and software quality assurance standards.

Therefore, the requirements should be stated from a purely external viewpoint. When using models to illus-

trate the requirements, remember that the model only indicates the external behavior, and does not specify a

design.

4.8 Embedding project requirements in the SRS

The SRS should address the software product, not the process of producing the software product.

Project requirements represent an understanding between the customer and the supplier about contractual

matters pertaining to production of software and thus should not be included in the SRS. These normally

include items such as

a) Cost;

b) Delivery schedules;

c) Reporting procedures;

d) Software development methods;

e) Quality assurance;

f) Validation and veriÞcation criteria;

g) Acceptance procedures.

Project requirements are speciÞed in other documents, typically in a software development plan, a software

quality assurance plan, or a statement of work.

5. The parts of an SRS

This clause discusses each of the essential parts of the SRS. These parts are arranged in Figure 1 in an

outline that can serve as an example for writing an SRS.

While an SRS does not have to follow this outline or use the names given here for its parts, a good SRS

should include all the information discussed here.

10 Copyright © 1998 IEEE. All rights reserved.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

Table of Contents

1. Introduction

1.1 Purpose

1.2 Scope

1.3 Definitions, acronyms, and abbreviations

1.4 References

1.5 Overview

2. Overall description

2.1 Product perspective

2.2 Product functions

2.3 User characteristics

2.4 Constraints

2.5 Assumptions and dependencies

3. Specific requirements (See 5.3.1 through 5.3.8 for explanations of possible

specific requirements. See also Annex A for several different ways of organizing

this section of the SRS.)

Appendixes

Index Figure 1ÑPrototype SRS outline

5.1 Introduction (Section 1 of the SRS)

The introduction of the SRS should provide an overview of the entire SRS. It should contain the following

subsections:

a) Purpose;

b) Scope;

c) DeÞnitions, acronyms, and abbreviations;

d) References;

e) Overview.

5.1.1 Purpose (1.1 of the SRS)

This subsection should

a) Delineate the purpose of the SRS;

b) Specify the intended audience for the SRS.

5.1.2 Scope (1.2 of the SRS)

This subsection should

a) Identify the software product(s) to be produced by name (e.g., Host DBMS, Report Generator, etc.);

b) Explain what the software product(s) will, and, if necessary, will not do;

c) Describe the application of the software being speciÞed, including relevant beneÞts, objectives, and

goals;

d) Be consistent with similar statements in higher-level speciÞcations (e.g., the system requirements

speciÞcation), if they exist. 11

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Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

5.1.3 DeÞnitions, acronyms, and abbreviations (1.3 of the SRS)

This subsection should provide the deÞnitions of all terms, acronyms, and abbreviations required to properly

interpret the SRS. This information may be provided by reference to one or more appendixes in the SRS or

by reference to other documents.

5.1.4 References (1.4 of the SRS)

This subsection should

a) Provide a complete list of all documents referenced elsewhere in the SRS;

b) Identify each document by title, report number (if applicable), date, and publishing organization;

c) Specify the sources from which the references can be obtained.

This information may be provided by reference to an appendix or to another document.

5.1.5 Overview (1.5 of the SRS)

This subsection should

a) Describe what the rest of the SRS contains;

b) Explain how the SRS is organized.

5.2 Overall description (Section 2 of the SRS)

This section of the SRS should describe the general factors that affect the product and its requirements. This

section does not state speciÞc requirements. Instead, it provides a background for those requirements, which

are deÞned in detail in Section 3 of the SRS, and makes them easier to understand.

This section usually consists of six subsections, as follows:

a) Product perspective;

b) Product functions;

c) User characteristics;

d) Constraints;

e) Assumptions and dependencies;

f) Apportioning of requirements.

5.2.1 Product perspective (2.1 of the SRS)

This subsection of the SRS should put the product into perspective with other related products. If the product

is independent and totally self-contained, it should be so stated here. If the SRS deÞnes a product that is a

component of a larger system, as frequently occurs, then this subsection should relate the requirements of

that larger system to functionality of the software and should identify interfaces between that system and the

software.

A block diagram showing the major components of the larger system, interconnections, and external inter-

faces can be helpful.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

This subsection should also describe how the software operates inside various constraints. For example,

these constraints could include

a) System interfaces;

b) User interfaces;

c) Hardware interfaces;

d) Software interfaces;

e) Communications interfaces;

f) Memory;

g) Operations;

h) Site adaptation requirements.

5.2.1.1 System interfaces

This should list each system interface and identify the functionality of the software to accomplish the system

requirement and the interface description to match the system.

5.2.1.2 User interfaces

This should specify the following:

a) The logical characteristics of each interface between the software product and its users. This

includes those conÞguration characteristics (e.g., required screen formats, page or window layouts,

content of any reports or menus, or availability of programmable function keys) necessary to accom-

plish the software requirements.

b) All the aspects of optimizing the interface with the person who must use the system. This may simply

comprise a list of doÕs and donÕts on how the system will appear to the user. One example may be a

requirement for the option of long or short error messages. Like all others, these requirements

should be veriÞable, e.g., Òa clerk typist grade 4 can do function X in Z min after 1 h of trainingÓ

rather than Òa typist can do function X.

Ó (This may also be speciÞed in the Software System

Attributes under a section titled Ease of Use.)

5.2.1.3 Hardware interfaces

This should specify the logical characteristics of each interface between the software product and the hard-

ware components of the system. This includes conÞguration characteristics (number of ports, instruction

sets, etc.). It also covers such matters as what devices are to be supported, how they are to be supported, and

protocols. For example, terminal support may specify full-screen support as opposed to line-by-line support.

5.2.1.4 Software interfaces

This should specify the use of other required software products (e.g., a data management system, an operat-

ing system, or a mathematical package), and interfaces with other application systems (e.g., the linkage

between an accounts receivable system and a general ledger system). For each required software product, the

following should be provided:

Ñ Name;

Ñ Mnemonic;

Ñ SpeciÞcation number;

Ñ Version number;

Ñ Source. 13

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IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

For each interface, the following should be provided:

Ñ Discussion of the purpose of the interfacing software as related to this software product.

Ñ DeÞnition of the interface in terms of message content and format. It is not necessary to detail any

well-documented interface, but a reference to the document deÞning the interface is required.

5.2.1.5 Communications interfaces

This should specify the various interfaces to communications such as local network protocols, etc.

5.2.1.6 Memory constraints

This should specify any applicable characteristics and limits on primary and secondary memory.

5.2.1.7 Operations

This should specify the normal and special operations required by the user such as

a) The various modes of operations in the user organization (e.g., user-initiated operations);

b) Periods of interactive operations and periods of unattended operations;

c) Data processing support functions;

d) Backup and recovery operations.

NOTEÑThis is sometimes speciÞed as part of the User Interfaces section.

5.2.1.8 Site adaptation requirements

This should

a) DeÞne the requirements for any data or initialization sequences that are speciÞc to a given site,

mission, or operational mode (e.g., grid values, safety limits, etc.);

b) Specify the site or mission-related features that should be modiÞed to adapt the software to a partic-

ular installation.

5.2.2 Product functions (2.2 of the SRS)

This subsection of the SRS should provide a summary of the major functions that the software will perform.

For example, an SRS for an accounting program may use this part to address customer account maintenance,

customer statement, and invoice preparation without mentioning the vast amount of detail that each of those

functions requires.

Sometimes the function summary that is necessary for this part can be taken directly from the section of the

higher-level speciÞcation (if one exists) that allocates particular functions to the software product. Note that

for the sake of clarity

a) The functions should be organized in a way that makes the list of functions understandable to the

customer or to anyone else reading the document for the Þrst time.

b) Textual or graphical methods can be used to show the different functions and their relationships.

Such a diagram is not intended to show a design of a product, but simply shows the logical relation-

ships among variables.

14 Copyright © 1998 IEEE. All rights reserved.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

5.2.3 User characteristics (2.3 of the SRS)

This subsection of the SRS should describe those general characteristics of the intended users of the product

including educational level, experience, and technical expertise. It should not be used to state speciÞc

requirements, but rather should provide the reasons why certain speciÞc requirements are later speciÞed in

Section 3 of the SRS.

5.2.4 Constraints (2.4 of the SRS)

This subsection of the SRS should provide a general description of any other items that will limit the devel-

operÕs options. These include

a) Regulatory policies;

b) Hardware limitations (e.g., signal timing requirements);

c) Interfaces to other applications;

d) Parallel operation;

e) Audit functions;

f) Control functions;

g) Higher-order language requirements;

h) Signal handshake protocols (e.g., XON-XOFF, ACK-NACK);

i) Reliability requirements;

j) Criticality of the application;

k) Safety and security considerations.

5.2.5 Assumptions and dependencies (2.5 of the SRS)

This subsection of the SRS should list each of the factors that affect the requirements stated in the SRS.

These factors are not design constraints on the software but are, rather, any changes to them that can affect

the requirements in the SRS. For example, an assumption may be that a speciÞc operating system will be

available on the hardware designated for the software product. If, in fact, the operating system is not avail-

able, the SRS would then have to change accordingly.

5.2.6 Apportioning of requirements (2.6 of the SRS)

This subsection of the SRS should identify requirements that may be delayed until future versions of the

system.

5.3 SpeciÞc requirements (Section 3 of the SRS)

This section of the SRS should contain all of the software requirements to a level of detail sufÞcient to

enable designers to design a system to satisfy those requirements, and testers to test that the system satisÞes

those requirements. Throughout this section, every stated requirement should be externally perceivable by

users, operators, or other external systems. These requirements should include at a minimum a description of

every input (stimulus) into the system, every output (response) from the system, and all functions performed

by the system in response to an input or in support of an output. As this is often the largest and most impor-

tant part of the SRS, the following principles apply:

a) SpeciÞc requirements should be stated in conformance with all the characteristics described in 4.3.

b) SpeciÞc requirements should be cross-referenced to earlier documents that relate.

c) All requirements should be uniquely identiÞable.

d) Careful attention should be given to organizing the requirements to maximize readability. 15

Copyright © 1998 IEEE. All rights reserved.

IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

Before examining speciÞc ways of organizing the requirements it is helpful to understand the various items

that comprise requirements as described in 5.3.1 through 5.3.7.

5.3.1 External interfaces

This should be a detailed description of all inputs into and outputs from the software system. It should

complement the interface descriptions in 5.2 and should not repeat information there.

It should include both content and format as follows:

a) Name of item;

b) Description of purpose;

c) Source of input or destination of output;

d) Valid range, accuracy, and/or tolerance;

e) Units of measure;

f) Timing;

g) Relationships to other inputs/outputs;

h) Screen formats/organization;

i) Window formats/organization;

j) Data formats;

k) Command formats;

l) End messages.

5.3.2 Functions

Functional requirements should deÞne the fundamental actions that must take place in the software in

accepting and processing the inputs and in processing and generating the outputs. These are generally listed

as ÒshallÓ statements starting with ÒThe system shallÉÓ

These include

a) Validity checks on the inputs

b) Exact sequence of operations

c) Responses to abnormal situations, including

1) Overßow

2) Communication facilities

3) Error handling and recovery

d) Effect of parameters

e) Relationship of outputs to inputs, including

1) Input/output sequences

2) Formulas for input to output conversion

It may be appropriate to partition the functional requirements into subfunctions or subprocesses. This does

not imply that the software design will also be partitioned that way.

5.3.3 Performance requirements

This subsection should specify both the static and the dynamic numerical requirements placed on the soft-

ware or on human interaction with the software as a whole. Static numerical requirements may include the

following:

a) The number of terminals to be supported;

b) The number of simultaneous users to be supported;

c) Amount and type of information to be handled.

16 Copyright © 1998 IEEE. All rights reserved.

IEEE

SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

Static numerical requirements are sometimes identiÞed under a separate section entitled Capacity.

Dynamic numerical requirements may include, for example, the numbers of transactions and tasks and the

amount of data to be processed within certain time periods for both normal and peak workload conditions.

All of these requirements should be stated in measurable terms.

For example,

95% of the transactions shall be processed in less than 1 s.

rather than,

An operator shall not have to wait for the transaction to complete.

NOTEÑNumerical limits applied to one speciÞc function are normally speciÞed as part of the processing subparagraph

description of that function.

5.3.4 Logical database requirements

This should specify the logical requirements for any information that is to be placed into a database. This

may include the following:

a) Types of information used by various functions;

b) Frequency of use;

c) Accessing capabilities;

d) Data entities and their relationships;

e) Integrity constraints;

f) Data retention requirements.

5.3.5 Design constraints

This should specify design constraints that can be imposed by other standards, hardware limitations, etc.

5.3.5.1 Standards compliance

This subsection should specify the requirements derived from existing standards or regulations. They may

include the following:

a) Report format;

b) Data naming;

c) Accounting procedures;

d) Audit tracing.

For example, this could specify the requirement for software to trace processing activity. Such traces are

needed for some applications to meet minimum regulatory or Þnancial standards. An audit trace requirement

may, for example, state that all changes to a payroll database must be recorded in a trace Þle with before and

after values.

5.3.6 Software system attributes

There are a number of attributes of software that can serve as requirements. It is important that required

attributes be speciÞed so that their achievement can be objectively veriÞed. Subclauses 5.3.6.1 through

5.3.6.5 provide a partial list of examples. 17

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IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

5.3.6.1 Reliability

This should specify the factors required to establish the required reliability of the software system at time of

delivery.

5.3.6.2 Availability

This should specify the factors required to guarantee a deÞned availability level for the entire system such as

checkpoint, recovery, and restart.

5.3.6.3 Security

This should specify the factors that protect the software from accidental or malicious access, use, modiÞca-

tion, destruction, or disclosure. SpeciÞc requirements in this area could include the need to

a) Utilize certain cryptographical techniques;

b) Keep speciÞc log or history data sets;

c) Assign certain functions to different modules;

d) Restrict communications between some areas of the program;

e) Check data integrity for critical variables.

5.3.6.4 Maintainability

This should specify attributes of software that relate to the ease of maintenance of the software itself. There

may be some requirement for certain modularity, interfaces, complexity, etc. Requirements should not be

placed here just because they are thought to be good design practices.

5.3.6.5 Portability

This should specify attributes of software that relate to the ease of porting the software to other host

machines and/or operating systems. This may include the following:

a) Percentage of components with host-dependent code;

b) Percentage of code that is host dependent;

c) Use of a proven portable language;

d) Use of a particular compiler or language subset;

e) Use of a particular operating system.

5.3.7 Organizing the speciÞc requirements

For anything but trivial systems the detailed requirements tend to be extensive. For this reason, it is recom-

mended that careful consideration be given to organizing these in a manner optimal for understanding. There

is no one optimal organization for all systems. Different classes of systems lend themselves to different orga-

nizations of requirements in Section 3 of the SRS. Some of these organizations are described in 5.3.7.1

through 5.3.7.7.

5.3.7.1 System mode

Some systems behave quite differently depending on the mode of operation. For example, a control system

may have different sets of functions depending on its mode: training, normal, or emergency. When organiz-

ing this section by mode, the outline in A.1 or A.2 should be used. The choice depends on whether interfaces

and performance are dependent on mode.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

5.3.7.2 User class

Some systems provide different sets of functions to different classes of users. For example, an elevator

control system presents different capabilities to passengers, maintenance workers, and Þre Þghters. When

organizing this section by user class, the outline in A.3 should be used.

5.3.7.3 Objects

Objects are real-world entities that have a counterpart within the system. For example, in a patient monitor-

ing system, objects include patients, sensors, nurses, rooms, physicians, medicines, etc. Associated with

each object is a set of attributes (of that object) and functions (performed by that object). These functions are

also called services, methods, or processes. When organizing this section by object, the outline in A.4 should

be used. Note that sets of objects may share attributes and services. These are grouped together as classes.

5.3.7.4 Feature

A feature is an externally desired service by the system that may require a sequence of inputs to effect the

desired result. For example, in a telephone system, features include local call, call forwarding, and confer-

ence call. Each feature is generally described in a sequence of stimulus-response pairs. When organizing this

section by feature, the outline in A.5 should be used.

5.3.7.5 Stimulus

Some systems can be best organized by describing their functions in terms of stimuli. For example, the func-

tions of an automatic aircraft landing system may be organized into sections for loss of power, wind shear,

sudden change in roll, vertical velocity excessive, etc. When organizing this section by stimulus, the outline

in A.6 should be used.

5.3.7.6 Response

Some systems can be best organized by describing all the functions in support of the generation of a

response. For example, the functions of a personnel system may be organized into sections corresponding to

all functions associated with generating paychecks, all functions associated with generating a current list of

employees, etc. The outline in A.6 (with all occurrences of stimulus replaced with response) should be used.

5.3.7.7 Functional hierarchy

When none of the above organizational schemes prove helpful, the overall functionality can be organized

into a hierarchy of functions organized by either common inputs, common outputs, or common internal data

access. Data ßow diagrams and data dictionaries can be used to show the relationships between and among

the functions and data. When organizing this section by functional hierarchy, the outline in A.7 should be

used.

5.3.8 Additional comments

Whenever a new SRS is contemplated, more than one of the organizational techniques given in 5.3.7.7 may

be appropriate. In such cases, organize the speciÞc requirements for multiple hierarchies tailored to the

speciÞc needs of the system under speciÞcation. For example, see A.8 for an organization combining user

class and feature. Any additional requirements may be put in a separate section at the end of the SRS.

There are many notations, methods, and automated support tools available to aid in the documentation of

requirements. For the most part, their usefulness is a function of organization. For example, when organizing

by mode, Þnite state machines or state charts may prove helpful; when organizing by object, object-oriented

19

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Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

analysis may prove helpful; when organizing by feature, stimulus-response sequences may prove helpful;

and when organizing by functional hierarchy, data ßow diagrams and data dictionaries may prove helpful.

In any of the outlines given in A.1 through A.8, those sections called ÒFunctional Requirement iÓ may be

described in native language (e.g., English), in pseudocode, in a system deÞnition language, or in four sub-

sections titled: Introduction, Inputs, Processing, and Outputs.

5.4 Supporting information

The supporting information makes the SRS easier to use. It includes the following:

a) Table of contents;

b) Index;

c) Appendixes.

5.4.1 Table of contents and index

The table of contents and index are quite important and should follow general compositional practices.

5.4.2 Appendixes

The appendixes are not always considered part of the actual SRS and are not always necessary. They may

include

a) Sample input/output formats, descriptions of cost analysis studies, or results of user surveys;

b) Supporting or background information that can help the readers of the SRS;

c) A description of the problems to be solved by the software;

d) Special packaging instructions for the code and the media to meet security, export, initial loading, or

other requirements.

When appendixes are included, the SRS should explicitly state whether or not the appendixes are to be

considered part of the requirements.

20 Copyright © 1998 IEEE. All rights reserved.

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SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

Annex A

(informative)

SRS templates

A.1 Template of SRS Section 3 organized by mode: Version 1

3. SpeciÞc requirements

3.1 External interface requirements

3.1.1 User interfaces

3.1.2 Hardware interfaces

3.1.3 Software interfaces

3.1.4 Communications interfaces

3.2 Functional requirements

3.2.1 Mode 1

3.2.1.1 Functional requirement 1.1

.

.

.

3.2.1.n Functional requirement 1.n

3.2.2 Mode 2

.

.

.

3.2.m Mode m

3.2.m.1 Functional requirement m.1

.

.

.

3.2.m.n Functional requirement m.n

3.3 Performance requirements

3.4 Design constraints

3.5 Software system attributes

3.6 Other requirements

A.2 Template of SRS Section 3 organized by mode: Version 2

3. SpeciÞc requirements

3.1. Functional requirements

3.1.1 Mode 1

3.1.1.1 External interfaces

3.1.1.1.1 User interfaces

3.1.1.1.2 Hardware interfaces

3.1.1.1.3 Software interfaces

3.1.1.1.4 Communications interfaces

3.1.1.2 Functional requirements

3.1.1.2.1 Functional requirement 1

.

.

. 21

Copyright © 1998 IEEE. All rights reserved.

IEEE

Std 830-1998 IEEE RECOMMENDED PRACTICE FOR

3.1.1.2.n Functional requirement n

3.1.1.3 Performance

3.1.2 Mode 2

.

.

.

3.1.m Mode m

3.2 Design constraints

3.3 Software system attributes

3.4 Other requirements

A.3 Template of SRS Section 3 organized by user class

3. SpeciÞc requirements

3.1 External interface requirements

3.1.1 User interfaces

3.1.2 Hardware interfaces

3.1.3 Software interfaces

3.1.4 Communications interfaces

3.2 Functional requirements

3.2.1 User class 1

3.2.1.1 Functional requirement 1.1

.

.

.

3.2.1.n Functional requirement 1.n

3.2.2 User class 2

.

.

.

3.2.m User class m

3.2.m.1 Functional requirement m.1

.

.

.

3.2.m.n Functional requirement m.n

3.3 Performance requirements

3.4 Design constraints

3.5 Software system attributes

3.6 Other requirements

A.4 Template of SRS Section 3 organized by object

3. SpeciÞc requirements

3.1 External interface requirements

3.1.1 User interfaces

3.1.2 Hardware interfaces

3.1.3 Software interfaces

3.1.4 Communications interfaces

3.2 Classes/Objects

3.2.1 Class/Object 1

22 Copyright © 1998 IEEE. All rights reserved.

IEEE

SOFTWARE REQUIREMENTS SPECIFICATIONS Std 830-1998

3.2.1.1 Attributes (direct or inherited)

3.2.1.1.1 Attribute 1

.

.

.

3.2.1.1.n Attribute n

3.2.1.2 Functions (services, methods, direct or inherited)

3.2.1.2.1 Functional requirement 1.1

.

.

.

3.2.1.2.m Functional requirement 1.m

3.2.1.3 Messages (communications received or sent)

3.2.2 Class/Object 2

.

.

.

3.2.p Class/Object p

3.3 Performance requirements

3.4 Design constraints

3.5 Software system attributes

3.6 Other requirements

A.5 Template of SRS Section 3 organized by feature

3. SpeciÞc requirements

3.1 External interface requirements

3.1.1 User interfaces

3.1.2 Hardware interfaces

3.1.3 Software interfaces

3.1.4 Communications interfaces

3.2 System features

3.2.1 System Feature 1

3.2.1.1 Introduction/Purpose of feature

3.2.1.2 Stimulus/Response sequence

3.2.1.3 Associated functional requirements

3.2.1.3.1 Functional requirement 1

.

.

.

3.2.1.3.n Functional requirement n

3.2.2 System feature 2

.

.

.

3.2.m System feature m

.

.

.

3.3 Performance requirements

3.4 Design constraints

3.5 Software system attributes

3.6 Other requirements 23

Copyright © 1998 IEEE. All rights reserved.


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A.A.: 2013-2014

I contenuti di questa pagina costituiscono rielaborazioni personali del Publisher cecilialll di informazioni apprese con la frequenza delle lezioni di Fondamenti di informatica e studio autonomo di eventuali libri di riferimento in preparazione dell'esame finale o della tesi. Non devono intendersi come materiale ufficiale dell'università Napoli Federico II - Unina o del prof Fassolino Rita.

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