The following is a standard template for a Software Requirements Specification document. This is the format required by the U.S. Government for all software contractors.

10.  PREPARATION INSTRUCTIONS -- 10.1 General Instructions (continued)

	c.	Title page or identifier with signature blocks.  The document shall include a title page 
containing, as applicable:  document number; volume number; version/revision indicator; 
security markings or other restrictions on the handling of the document; date; document title; 
name, abbreviation, and any other identifier for the system, subsystem, or item to which the 
document applies; contract number; CDRL item number; organization for which the 
document has been prepared; name and address of the preparing organization; distribution 
statement; and signature blocks for the developer representative authorized to release the 
document, the acquirer representative authorized to approve the document, and the dates 
of release/approval.  For data in a database or other alternative form, this information shall 
be included on external and internal labels or by equivalent identification methods.

	d.	Table of contents.  The document shall contain a table of contents providing the number, 
title, and page number of each titled paragraph, figure, table, and appendix.  For data in a 
database or other alternative form, this information shall consist of an internal or external 
table of contents containing pointers to, or instructions for accessing, each paragraph, 
figure, table, and appendix or their equivalents.

	e.	Page numbering/labeling.  Each page shall contain a unique page number and display the 
document number, including version, volume, and date, as applicable.  For data in a 
database or other alternative form, files, screens, or other entities shall be assigned names 
or numbers in such a way that desired data can be indexed and accessed.

	f.	Response to tailoring instructions.  If a paragraph is tailored out of this DID, the resulting 
document shall contain the corresponding paragraph number and title, followed by "This 
paragraph has been tailored out."  For data in a database or other alternative form, this 
representation need occur only in the table of contents or equivalent.

	g.	Multiple paragraphs and subparagraphs.  Any section, paragraph, or subparagraph in this 
DID may be written as multiple paragraphs or subparagraphs to enhance readability.

	h.	Standard data descriptions.  If a data description required by this DID has been published in 
a standard data element dictionary specified in the contract, reference to an entry in that 
dictionary is preferred over including the description itself.

	i.		Substitution of existing documents.  Commercial or other existing documents may be 
substituted for all or part of the document if they contain the required data.

10.2  Content requirements.  Content requirements begin on the following page.  The numbers 
shown designate the paragraph numbers to be used in the document.  Each such number is 
understood to have the prefix "10.2" within this DID.  For example, the paragraph numbered 1.1 is 
understood to be paragraph 10.2.1.1 within this DID.

1.	Scope.  This section shall be divided into the following paragraphs.

1.1		Identification.  This paragraph shall contain a full identification of the system and the 
software to which this document applies, including, as applicable, identification number(s), 
title(s), abbreviation(s), version number(s), and release number(s).

1.2		System overview.  This paragraph shall briefly state the purpose of the system and the 
software to which this document applies.  It shall describe the general nature of the system and 
software; summarize the history of system development, operation, and maintenance; identify 
the project sponsor, acquirer, user, developer, and support agencies; identify current and 
planned operating sites; and list other relevant documents.

1.3		Document overview.  This paragraph shall summarize the purpose and contents of this 
document and shall describe any security or privacy considerations associated with its use.  

2.	Referenced documents.  This section shall list the number, title, revision, and date of all 
documents referenced in this specification.  This section shall also identify the source for all 
documents not available through normal Government stocking activities.

3.	Requirements.  This section shall be divided into the following paragraphs to specify the 
CSCI requirements, that is, those characteristics of the CSCI that are conditions for its 
acceptance.  CSCI requirements are software requirements generated to satisfy the system 
requirements allocated to this CSCI.  Each requirement shall be assigned a project-unique 
identifier to support testing and traceability and shall be stated in such a way that an objective 
test can be defined for it.  Each requirement shall be annotated with associated qualification 
method(s) (see section 4) and traceability to system (or subsystem, if applicable) requirements 
(see section 5.a) if not provided in those sections.  The degree of detail to be provided shall be 
guided by the following rule:  Include those characteristics of the CSCI that are conditions for 
CSCI acceptance; defer to design descriptions those characteristics that the acquirer is willing 
to leave up to the developer.  If there are no requirements in a given paragraph, the paragraph 
shall so state.  If a given requirement fits into more than one paragraph, it may be stated once 
and referenced from the other paragraphs.  

3.1		Required states and modes.  If the CSCI is required to operate in more than one state or 
mode having requirements distinct from other states or modes, this paragraph shall identify and 
define each state and mode.  Examples of states and modes include:  idle, ready, active, post-
use analysis, training, degraded, emergency, backup, wartime, peacetime.  The distinction 
between states and modes is arbitrary.  A CSCI may be described in terms of states only, 
modes only, states within modes, modes within states, or any other scheme that is useful.  If no 
states or modes are required, this paragraph shall so state, without the need to create artificial 
distinctions. If states and/or modes are required, each requirement or group of requirements in 
this specification shall be correlated to the states and modes.  The correlation may be indicated 
by a table or other method in this paragraph, in an appendix referenced from this paragraph, or 
by annotation of the requirements in the paragraphs where they appear.




3.2		CSCI capability requirements.  This paragraph shall be divided into subparagraphs to 
itemize the requirements associated with each capability of the CSCI.  A "capability" is defined 
as a group of related requirements.  The word "capability" may be replaced with "function," 
"subject," "object," or other term useful for presenting the requirements.  

3.2.x		(CSCI capability).  This paragraph shall identify a required CSCI capability and shall 
itemize the requirements associated with the capability.  If the capability can be more clearly 
specified by dividing it into constituent capabilities, the constituent capabilities shall be specified 
in subparagraphs.  The requirements shall specify required behavior of the CSCI and shall 
include applicable parameters, such as response times, throughput times, other timing 
constraints, sequencing, accuracy, capacities (how much/how many), priorities, continuous 
operation requirements, and allowable deviations based on operating conditions.  The 
requirements shall include, as applicable, required behavior under unexpected, unallowed, or 
"out of bounds" conditions, requirements for error handling, and any provisions to be 
incorporated into the CSCI to provide continuity of operations in the event of emergencies.  
Paragraph 3.3.x of this DID provides a list of topics to be considered when specifying 
requirements regarding inputs the CSCI must accept and outputs it must produce.

3.3		CSCI external interface requirements.  This paragraph shall be divided into subparagraphs 
to specify the requirements, if any, for the CSCI's external interfaces.  This paragraph may 
reference one or more Interface Requirements Specifications (IRSs) or other documents 
containing these requirements.

3.3.1		Interface identification and diagrams.  This paragraph shall identify the required 
external interfaces of the CSCI (that is, relationships with other entities that involve sharing, 
providing or exchanging data).  The identification of each interface shall include a project-
unique identifier and shall designate the interfacing entities (systems, configuration items, 
users, etc.) by name, number, version, and documentation references, as applicable.  The 
identification shall state which entities have fixed interface characteristics (and therefore impose 
interface requirements on interfacing entities) and which are being developed or modified (thus 
having interface requirements imposed on them).  One or more interface diagrams shall be 
provided to depict the interfaces.

3.3.x		(Project-unique identifier of interface).  This paragraph (beginning with 3.3.2) shall 
identify a CSCI external interface by project-unique identifier, shall briefly identify the interfacing 
entities, and shall be divided into subparagraphs as needed to state the requirements imposed 
on the CSCI to achieve the interface.  Interface characteristics of the other entities involved in 
the interface shall be stated as assumptions or as "When [the entity not covered] does this, the 
CSCI shall...," not as requirements on the other entities.  This paragraph may reference other 
documents (such as data dictionaries, standards for communication protocols, and standards 
for user interfaces) in place of stating the information here.  The requirements shall include the 
following, as applicable, presented in any order suited to the requirements, and shall note any 
differences in these characteristics from the point of view of the interfacing entities (such as 
different expectations about the size, frequency, or other characteristics of data elements):

	a.	Priority that the CSCI must assign the interface

	b.	Requirements on the type of interface (such as real-time data transfer, storage-and-
retrieval of data, etc.) to be implemented

	c.	Required characteristics of individual data elements that the CSCI must provide, store, 
send, access, receive, etc., such as:
			1)	Names/identifiers
				a)	Project-unique identifier
				b)	Non-technical (natural-language) name
				c)	DoD standard data element name
				d)	Technical name (e.g., variable or field name in code or database)
				e)	Abbreviation or synonymous names
			2)	Data type (alphanumeric, integer, etc.)
			3)	Size and format (such as length and punctuation of a character string)
			4)	Units of measurement (such as meters, dollars, nanoseconds)
			5)	Range or enumeration of possible values (such as 0-99)
			6)	Accuracy (how correct) and precision (number of significant digits)
			7)	Priority, timing, frequency, volume, sequencing, and other constraints, such as 
whether the data element may be updated and whether business rules apply
			8)	Security and privacy constraints
			9)	Sources (setting/sending entities) and recipients (using/receiving entities)

	d.	Required characteristics of data element assemblies (records, messages, files, arrays, 
displays, reports, etc.) that the CSCI must provide, store, send, access, receive, etc., 
such as:
			1)	Names/identifiers
				a)	Project-unique identifier
				b)	Non-technical (natural language) name
				c)	Technical name (e.g., record or data structure name in code or database)
				d)	Abbreviations or synonymous names
			2)	Data elements in the assembly and their structure (number, order, grouping)
			3)	Medium (such as disk) and structure of data elements/assemblies on the medium
			4)	Visual and auditory characteristics of displays and other outputs (such as colors, 
layouts, fonts, icons and other display elements, beeps, lights)
			5)	Relationships among assemblies, such as sorting/access characteristics
			6)	Priority, timing, frequency, volume, sequencing, and other constraints, such as 
whether the assembly may be updated and whether business rules apply
			7)	Security and privacy constraints
			8)	Sources (setting/sending entities) and recipients (using/receiving entities)


	e.	Required characteristics of communication methods that the CSCI must use for the 
interface, such as:
			1)	Project-unique identifier(s)
			2)	Communication links/bands/frequencies/media and their characteristics
			3)	Message formatting
			4)	Flow control (such as sequence numbering and buffer allocation)
			5)	Data transfer rate, whether periodic/aperiodic, and interval between transfers
			6)	Routing, addressing, and naming conventions
			7)	Transmission services, including priority and grade
			8)	Safety/security/privacy considerations, such as encryption, user authentication, 
compartmentalization, and auditing

	f.	Required characteristics of protocols the CSCI must use for the interface, such as:
			1)	Project-unique identifier(s)
			2)	Priority/layer of the protocol
			3)	Packeting, including fragmentation and reassembly, routing, and addressing
			4)	Legality checks, error control, and recovery procedures
			5)	Synchronization, including connection establishment, maintenance, termination
			6)	Status, identification, and any other reporting features

	g.	Other required characteristics, such as physical compatibility of the interfacing entities 
(dimensions, tolerances, loads, plug compatibility, etc.), voltages, etc.

3.4		CSCI internal interface requirements.  This paragraph shall specify the requirements, if 
any, imposed on interfaces internal to the CSCI.  If all internal interfaces are left to the design, 
this fact shall be so stated.  If such requirements are to be imposed, paragraph 3.3 of this DID 
provides a list of topics to be considered.

3.5		CSCI internal data requirements.  This paragraph shall specify the requirements, if any, 
imposed on data internal to the CSCI.  Included shall be requirements, if any, on databases and 
data files to be included in the CSCI.  If all decisions about internal data are left to the design, 
this fact shall be so stated.  If such requirements are to be imposed, paragraphs 3.3.x.c and 
3.3.x.d of this DID provide a list of topics to be considered.  

3.6		Adaptation requirements.  This paragraph shall specify the requirements, if any, 
concerning installation-dependent data to be provided by the CSCI (such as site-dependent 
latitude and longitude or site-dependent state tax codes) and operational parameters that the 
CSCI is required to use that may vary according to operational needs (such as parameters 
indicating operation-dependent targeting constants or data recording).






3.7		Safety requirements.  This paragraph shall specify the CSCI requirements, if any, 
concerned with preventing or minimizing unintended hazards to personnel, property, and the 
physical environment.  Examples include safeguards the CSCI must provide to prevent 
inadvertent actions (such as accidentally issuing an "auto pilot off" command) and non-actions 
(such as failure to issue an intended "auto pilot off" command).  This paragraph shall include 
the CSCI requirements, if any, regarding nuclear components of the system, including, as 
applicable, prevention of inadvertent detonation and compliance with nuclear safety rules.

3.8		Security and privacy requirements.  This paragraph shall specify the CSCI requirements, if 
any, concerned with maintaining security and privacy.  These requirements shall include, as 
applicable, the security/privacy environment in which the CSCI must operate, the type and 
degree of security or privacy to be provided, the security/privacy risks the CSCI must withstand, 
required safeguards to reduce those risks, the security/privacy policy that must be met, the 
security/privacy accountability the CSCI must provide, and the criteria that must be met for 
security/privacy certification/accreditation.

3.9		CSCI environment requirements.  This paragraph shall specify the requirements, if any, 
regarding the environment in which the CSCI must operate.  Examples include the computer 
hardware and operating system on which the CSCI must run.  (Additional requirements 
concerning computer resources are given in the next paragraph.)

3.10	Computer resource requirements.  This paragraph shall be divided into the following 
subparagraphs.

3.10.1	Computer hardware requirements.  This paragraph shall specify the requirements, if 
any, regarding computer hardware that must be used by the CSCI.  The requirements shall 
include, as applicable, number of each type of equipment, type, size, capacity, and other 
required characteristics of processors, memory, input/output devices, auxiliary storage, 
communications/network equipment, and other required equipment.

3.10.2	Computer hardware resource utilization requirements.  This paragraph shall specify 
the requirements, if any, on the CSCI's computer hardware resource utilization, such as 
maximum allowable use of processor capacity, memory capacity, input/output device capacity, 
auxiliary storage device capacity, and communications/network equipment capacity.  The 
requirements (stated, for example, as percentages of the capacity of each computer hardware 
resource) shall include the conditions, if any, under which the resource utilization is to be 
measured.

3.10.3	Computer software requirements.  This paragraph shall specify the requirements, if 
any, regarding computer software that must be used by, or incorporated into, the CSCI.  
Examples include operating systems, database management systems, communications/ 
network software, utility software, input and equipment simulators, test software, and 
manufacturing software.  The correct nomenclature, version, and documentation references of 
each such software item shall be provided.

3.10.4	Computer communications requirements.  This paragraph shall specify the additional 
requirements, if any, concerning the computer communications that must be used by the CSCI.  
Examples include geographic locations to be linked; configuration and network topology; 
transmission techniques; data transfer rates; gateways; required system use times; type and 
volume of data to be transmitted/received; time boundaries for transmission/ 
reception/response; peak volumes of data; and diagnostic features.

3.11		Software quality factors.  This paragraph shall specify the CSCI requirements, if any, 
concerned with software quality factors identified in the contract or derived from a higher level 
specification.  Examples include quantitative requirements regarding CSCI functionality (the 
ability to perform all required functions), reliability (the ability to perform with correct, consistent 
results), maintainability (the ability to be easily corrected), availability (the ability to be accessed 
and operated when needed), flexibility (the ability to be easily adapted to changing 
requirements), portability (the ability to be easily modified for a new environment), reusability 
(the ability to be used in multiple applications), testability (the ability to be easily and thoroughly 
tested), usability (the ability to be easily learned and used), and other attributes.

3.12		Design and implementation constraints.  This paragraph shall specify the require-
ments, if any, that constrain the design and implementation of the CSCI.  These requirements 
may be specified by reference to appropriate commercial or military standards and 
specifications.  Examples include requirements concerning:  

	a.	Use of a particular CSCI architecture or requirements on the architecture, such as 
required databases or other software units; use of standard, military, or existing 
components; or use of Government/acquirer-furnished property (equipment, 
information, or software)

	b.	Use of particular design or implementation standards; use of particular data standards; 
use of a particular programming language

	c.	Flexibility and expandability that must be provided to support anticipated areas of 
growth or changes in technology, threat, or mission 

3.13		Personnel-related requirements.  This paragraph shall specify the CSCI requirements, 
if any, included to accommodate the number, skill levels, duty cycles, training needs, or other 
information about the personnel who will use or support the CSCI.  Examples include 
requirements for number of simultaneous users and for built-in help or training features.  Also 
included shall be the human factors engineering requirements, if any, imposed on the CSCI.  
These requirements shall include, as applicable, considerations for the capabilities and 
limitations of humans; foreseeable human errors under both normal and extreme conditions; 
and specific areas where the effects of human error would be particularly serious.  Examples 
include requirements for color and duration of error messages, physical placement of critical 
indicators or keys, and use of auditory signals.

3.14		Training-related requirements.  This paragraph shall specify the CSCI requirements, if 
any, pertaining to training.  Examples include training software to be included in the CSCI.


3.15		Logistics-related requirements.  This paragraph shall specify the CSCI requirements, if 
any, concerned with logistics considerations.  These considerations may include:  system 
maintenance, software support, system transportation modes, supply-system requirements, 
impact on existing facilities, and impact on existing equipment.

3.16		Other requirements.  This paragraph shall specify additional CSCI requirements, if 
any, not covered in the previous paragraphs.  

3.17		Packaging requirements.  This section shall specify the requirements, if any, for 
packaging, labeling, and handling the CSCI for delivery (for example, delivery on 8 track 
magnetic tape labelled and packaged in a certain way).  Applicable military specifications and 
standards may be referenced if appropriate.  

3.18		Precedence and criticality of requirements.  This paragraph shall specify, if applicable, 
the order of precedence, criticality, or assigned weights indicating the relative importance of the 
requirements in this specification.  Examples include identifying those requirements deemed 
critical to safety, to security, or to privacy for purposes of singling them out for special 
treatment.  If all requirements have equal weight, this paragraph shall so state.

4.	Qualification provisions.  This section shall define a set of qualification methods and shall 
specify for each requirement in Section 3 the method(s) to be used to ensure that the 
requirement has been met.  A table may be used to present this information, or each 
requirement in Section 3 may be annotated with the method(s) to be used.  Qualification 
methods may include:

	a.	Demonstration:  The operation of the CSCI, or a part of the CSCI, that relies on 
observable functional operation not requiring the use of instrumentation, special test 
equipment, or subsequent analysis.

	b.	Test:  The operation of the CSCI, or a part of the CSCI, using instrumentation or other 
special test equipment to collect data for later analysis.

	c.	Analysis:  The processing of accumulated data obtained from other qualification 
methods.  Examples are reduction, interpretation, or extrapolation of test results.

	d.	Inspection:  The visual examination of CSCI code, documentation, etc.

	e.	Special qualification methods:  Any special qualification methods for the CSCI, such as 
special tools, techniques, procedures, facilities, and acceptance limits.  

5.	Requirements traceability.  This paragraph shall contain:

	a.	Traceability from each CSCI requirement in this specification to the system (or 
subsystem, if applicable) requirements it addresses.  (Alternatively, this traceability 
may be provided by annotating each requirement in Section 3.) 


			Note:  Each level of system refinement may result in requirements not directly 
traceable to higher-level requirements.  For example, a system architectural design 
that creates multiple CSCIs may result in requirements about how the CSCIs will 
interface, even though these interfaces are not covered in system requirements.  Such 
requirements may be traced to a general requirement such as "system 
implementation" or to the system design decisions that resulted in their generation.

	b.	Traceability from each system (or subsystem, if applicable) requirement allocated to 
this CSCI to the CSCI requirements that address it.  All system (subsystem) 
requirements allocated to this CSCI shall be accounted for.  Those that trace to CSCI 
requirements contained in IRSs shall reference those IRSs.  

6.	Notes.  This section shall contain any general information that aids in understanding this 
specification (e.g., background information, glossary, rationale).  This section shall include an 
alphabetical listing of all acronyms, abbreviations, and their meanings as used in this document 
and a list of any terms and definitions needed to understand this document.

A.	Appendixes.  Appendixes may be used to provide information published separately for 
convenience in document maintenance (e.g., charts, classified data).  As applicable, each 
appendix shall be referenced in the main body of the document where the data would normally 
have been provided.  Appendixes may be bound as separate documents for ease in handling.  
Appendixes shall be lettered alphabetically (A, B, etc.).