System-Specifications-ISSwscacchi/SA/Analysis/Concepts/Syste… · Web viewSystem Specifications...

System Specifications for an Information Sharing System (ISS): Generic Reusable Form

Walt Scacchi

([email protected])

M271/F271

Preliminary Revision: 22:30, 12 October 2001

Fall 2001

People roles: who uses <! -- an ISS

Processes: what do they do

Inputs: what information do they put into <! -- an ISS

Outputs: what information can they get out of <! -- an ISS

System Components: what are the major software components of <! -- an ISS

Note: What follows represents a high-level view of the specifications of <! -- an ISS system (either a Global Peer-to-Peer File/Application Sharing System or an Enterprise (Web) Portal). It does NOT specify mid-level or low-level system features or operations. Thus, this is not a complete specification of the implementation of <! -- an ISS. As such, when examining this system specification document, if you identify any system-related items that are missing or mis-stated, please bring them to the attention of the author.

ISS Domain Variables

You can find and replace the following variables in your project, if and when appropriate, with the reuse patterns indicated here:

<! -- an ISS -- The name of your enterprise information sharing system, global P2P file sharing system, or enterprise portal. This system encapsulates access to vendors that provide the product from which the system is developed or used during operation. It also

mailto:[email protected]

encapsulates any Application Service Providers (ASPs) that provide outsourced or remote application services on the basis of a licensing or fee-for-service arrangement.

<! -- Institution -- A background community that names the enterprise in which your ISS is situated.

<! -- Sponsor -- A background community of people who authorize, fund, promote or otherwise advocate the development and usage of an ISS.

<! -- Authors -- People/actors who create and edit content managed by the ISS and served to End-Users.

<! -- Publishers -- People/actors who solicit content from Authors for marketing and dissemination.

<! -- End-Users -- People/actors who are the main users of the ISS on a regular basis.

<! -- ISS System Development Staff -- People/actors who develop an ISS for an enterprise with the support of one/more Sponsors.

<! -- Asynchronous messaging system -- A "connection-less" system for transmitting messages (or message content) from one person/system to one/more other persons/systems, when convenience or network traffic permits. Can scale to millions of users, though most applications involve the distribution of messages to no more than a few dozen people.

<! -- Synchronous messaging system -- A "connection-oriented" system for on-demand transmitting messages (or message content) from one person/system to one/more other persons/systems. Also employed in "peer-to-peer" applications like those for global file sharing (e.g., Napster, Gnutella, FreeNet).

People (stakeholders, actors, agents/ etc.) roles for <! -- an ISS

Guidelines/Notes:

-- Identify roles as named objects (in boldface) and organize roles in a hierarchical abstraction.

-- Provide a brief narrative description of what people do in each role.

-- Identify concerns/issues for people in each role.

<! -- Institution: One or more institutions (e.g., a business enterprise, a government agency, a university) provides the overall enterprise setting and workplace associated with the development, use, and evolution of <! -- an ISS. The <! -- Sponsor serves as the Executive that has committed resources to support <! -- an ISS and to encourage its routine usage among the other people at the <! -- Institution.

Concern: The institution operates either as a for-profit or non-profit enterprise. The institution seeks to offer products or services consistent with its mission and strategic objectives, while at the same time adhering to all applicable laws and community values. The institution may disconnect, terminate, or disassociate itself from activities or operations found to be in conflict with its mission, objectives, applicable laws and community values.

<! -- End-Users:

Download authored content and other <! -- Institution event information from <! -- an ISS

Create and upload (asynchronous or synchronous) messages and (user) information

Concerns:

<! -- End-Users are encouraged by <! -- Sponsor to use <! -- an ISS to download content, communicate and discuss content with other <! -- End-Users and <! -- Authors as a way to learn more about the content. End-users may include other users previously affiliated with the <! -- Institution, such as "alumni".

<! -- Authors:

Create content for course(s), then send it to <! -- Publishers for edit and upload into <! -- an ISS

Create content for course(s), then upload it into <! -- an ISS

Download existing content for course(s) from <! -- an ISS, edit it, then upload edited content back into <! -- an ISS

Concerns:

<! -- Authors are encouraged by <! -- Sponsor to use <! -- an ISS to create, upload, edit and download content for <! -- Institution courses.

<! -- Sponsor:

Promote usage of <! -- an ISS by <! -- Authors, <! -- End-Users, <! -- Publishers.

Create/edit content guidelines for <! -- Authors or <! -- End-Users

Concerns:

Fund the development, usage and maintenance of <! -- an ISS at <! -- Institution.

Delegate responsibility to manage <! -- an ISS operations to <! -- Institution <! -- IS development staff.

Promote the existence and capabilities of <! -- an ISS to other institutions and users to bring more recognition, funding, and end-users to <! -- Institution.

<! -- Publishers:

Receive content from <! -- Authors (via email, fax or paper), edit if needed, then upload content into <! -- an ISS

Check content to see if minimum content object(s) has been entered.

Concern: Assist <! -- Authors in getting content into <! -- an ISS

<! -- IS System Development Staff:

Develop, operate and maintain the <! -- an ISS system hardware, software and (data) network services. Develop, operate and maintain the logical and physical data models and repository that organize, store and retrieve content as part of <! -- an ISS.

Concerns:

Organize and provide centralized IS support and online content management services for

all <! -- an ISS users.

Help <! -- Authors, <! -- End-Users, <! -- Publishers and <! -- Sponsor in their use of <! -- an ISS and its components.

<! -- an ISS Role Hierarchy

Processes for <! -- an ISS

Guidelines/Notes (Updated 12 October 2001):

Insert information for your project between the <tags associated with each item

Identify processes as named objects (in boldface) and organize processes in a hierarchical abstraction.

<Process-Identifier </Process-Identifier

Provide a brief narrative description of how the process is performed.

<Narrative </Narrative

Name of the person who created the first/original version of the process specification

<Author </Author

A timestamp in the form, year/month/day/hour/minute (e.g., 2001/10/12/21:00), to designate when the process specification was last updated.

<Version </Version

Name of the person who last created or modified the version of the process specification associated with the timestamp value.

<Last-Modified-By </Last-Modified-By

Identify the People roles associated with the Process

<People-Roles </People-Roles

Identify the Objects (using name of object class) that are manipulated by the Process

Input Objects <Input-Objects </Input-Objects

Output Objects <Output-Objects </Output-Objects

Specify the Process in steps that associate what People perform what actions (relations/verbs) on what Objects using what System Components.

Describe the Normal scenarios.

Check for and handle Exception scenarios.

Check for Errors as the first step in a process.

<Process </Process

Identify the System Components that support the Process

<Process-System-Components </Process-System-Components

A generic specification process template follows on the next page. Copy and reuse (specialize--fill in the blanks) it for each specification process in your project.

System Process Specification Template: Copy and reuse as needed; then insert your project-specific information between the beginning <tag and ending </tag.

(Updated: 12 October 2001)

<Process-Identifier </Process-Identifier

<Narrative </Narrative

<Author </Author

<Version </Version

<Last-Modified-By </Last-Modified-By

<People-Roles </People-Roles

<Input-Objects </Input-Objects

<Output-Objects </Output-Objects

<Process </Process

<Process-System-Components </Process-System-Components

System Specification of the following Processes

Use <! -- an ISS to Manage <! -- Institution Content

Create Content, Edit and Upload it into <! -- an ISS

Edit, Upload and Check Content for <! -- Authors

Download Content for Examination or Review

Upload messages or personal information

Do Email

Do User Messaging

Access other Web Content via <!-- an ISS

Manage <! -- an ISS Content

Develop and Test <! -- an ISS

<Process_Identifier

Use <! -- an ISS to Manage <! -- Institution Content

</Process-Identifier

<Narrative

<! -- Institution <! -- End-Users, <! -- Authors, <! -- Publishers, and <! -- IS development staff use <! -- an ISS to access, browse/download, edit/update content associated with <! -- Institution courses.

</Narrative

<AuthorWalt Scacchi</Author

<Version2001/10/12/22:00</Version

<Last-Modified-ByWalt Scacchi</Last-Modified-By

<People-Roles

<! -- Institution, <! -- End-Users, <! -- Authors, <! -- Publishers, and <! -- IS development staff, <! -- Sponsor

</People-Roles

<Input-Objects

content objects

</Input-Objects

<Output-Objects

views (copies) of content objects

</Output-Objects

<Process

All users (people) use <! -- an ISS to organize, store and retrieve content object types approved by users and implemented by <! -- IS Development Staff

(Exception): Only users who are authorized to access (login) to <! -- an ISS can access or manage its contents

User error: Users identities (at login) that are not recognized or authorized do not get to

access content managed by <! -- an ISS

System error: If <! -- an ISS server is not available, authorized users cannot access its content

</Process

<Process-System-Components

All <! -- an ISS system components in operation.

</Process-System-Components

Return to System Process Specifications

<Process_Identifier

Create Content, Edit and Upload it into <! -- an ISS

</Process_Identifier

<Narrative

<! -- Authors create high-quality content that they edit/upload into <! -- an ISS for access by <! -- End-Users or others at <! -- Institution.

</Narrative




<People-Roles

<! -- Authors

</People-Roles

<Input-Objects

content objects

</Input-Objects

<Output-Objects


</Output-Objects

<Process

<! -- Authors create (insert) new content into content representation (created by <! -- IS Development Staff) or edit (update) existing content already created by an <! -- Authors.

<! -- Authors can transmit the content they create to <! -- Publishers for edit and upload into <! -- an ISS, else <! -- Authors upload their content into <! -- an ISS

<! -- Authors/staff can only upload one type of content at a time into <! -- an ISS

(Exception) <! -- an ISS will allow existing content to be copied from one content object to another without upload.

<! -- Authors can only edit (update) content they have individually created

(Exception) <! -- Authors may copy and paste content created by other <! -- Authors from one part of <! -- an ISS into their content.

User error: <! -- an ISS cannot verify if content uploaded is correct. User is responsible for correctness of content

System error: <! -- an ISS will not allow content edit/upload if the <! -- an ISS DBMS is not available.

</Process


<! -- Authors can select any tools available to them to create content. <! -- Authors can edit content entered and stored within a Database Management System or Network File Server incorporated within <! -- an ISS via an Input Object content form accessed with a Web (client) Browser, by directly editing the content in the form.



<Process-Identifier

Edit, Upload and Check Content for <! -- Authors


<Narrative

<! -- Publishers edit and upload content that <! -- Authors have created and forwarded to them to

post in <! -- an ISS.

</Narrative




<People-Roles

<! -- Publishers, <! -- Authors

</People-Roles

<Input-Objects

content objects

</Input-Objects

<Output-Objects


</Output-Objects

<Process

<! -- Authors can transmit the content they create to <! -- Publishers for edit and upload into <! -- an ISS

<! -- Publishers can upload one type of content at a time into <! -- an ISS

(Exception) <! -- an ISS will allow existing content to be copied from one content object to another without upload.

User error: <! -- an ISS cannot verify if content uploaded is correct. Users are responsible for correctness of content

System error: <! -- an ISS will not allow content edit/upload if the <! -- an ISS DBMS is not available

</Process


<! -- Publishers can select any tools available to them to edit content created by <! -- Authors. <! -- Publishers can edit content entered and stored within a Database Management System or Network File Server incorporated within <! -- an ISS via an Input Object content form accessed with a Web (client) Browser, by directly editing the content in the form.



<Process-Identifier

Download Content for Examination or Review


<Narrative

<! -- End-Users, <! -- Publishers, and <! -- Authors regularly browse/download content for courses posted in <! -- an ISS. The <! -- Sponsor and <! -- IS development staff may less frequently download content from <! -- an ISS.

</Narrative




<People-Roles

<! -- End-Users, <! -- Publishers, <! -- Authors, <! -- Sponsor and <! -- IS development staff

</People-Roles

<Input-Objects

Content navigation selection commands (e.g., mouse clicks on hyperlinked content, pull-down menu item selection, check box selection)

</Input-Objects

<Output-Objects

views (copies) of selected content objects

</Output-Objects

<Process

Users (<! -- Authors and <! -- End-users) can search and download course content:

for content <! -- Authors have created; or

for messages or personal info. entered by <! -- End-users; or

(Exception) from content designated for sharing by all <! -- Authors (content and linked materials)

User error: <! -- an ISS will not allow access to content except as allowed by <! -- Sponsor policy

System error: <! -- an ISS will not allow search or download of <! -- an ISS content if the <! -- an ISS DBMS is unavailable.

</Process


Web (client) Browser, <! -- an ISS Web server, Database Management System, Network File Server.



<Process-Identifier

Upload messages or personal information


<Narrative

<! -- End-Users are encouraged to upload/post messages using <! -- Asynchronous messaging system or <! -- Synchronous messaging system that can be browsed/downloaded by other users of <! -- an ISS. <! -- Authors may also upload personal information for storage within and dissemination from <! -- an ISS.

</Narrative




<People-Roles

<! -- End-Users, <! -- Authors

</People-Roles

<Input-Objects

Messages (text), file attachments, input submission selection commands (e.g., mouse clicks on

button)

</Input-Objects

<Output-Objects

views (copies) of message content, file attachments in client display

</Output-Objects

<Process

<! -- End-users can download, update, then upload personal information for sharing with other users.

<! -- End-users (end-users) can upload messages for sharing with other <! -- End-users at any time.

(Exception): <! -- End-users can send and receive messages from other <! -- End-users via <! -- an ISS, without uploading these messages into <! -- an ISS

User error: <! -- an ISS cannot verify if content uploaded is correct in any sense. User is responsible for correctness of content

System error: <! -- an ISS will not allow content edit/upload if the <! -- an ISS DBMS is not available

</Process


Separate or embedded <! -- Asynchronous messaging system, <! -- Synchronous messaging system client (peer).



<Process-Identifier

Do Email


<Narrative

All users can send and receive Email content and file attachments, either from within or external to <! -- an ISS.

</Narrative




<People-Roles


</People-Roles

<Input-Objects

Email content, email file attachments

</Input-Objects

<Output-Objects

copies (views) of Email content, email file attachments

</Output-Objects

<Process

Any registered user can access internal or external email systems via <! -- an ISS to create, upload, download, update then upload messages for other users at any time.

<! -- an ISS does not manage or store email messages or message services

(Exception): Users can create, upload, download, update then upload email messages via <! -- an ISS, without uploading these messages into <! -- an ISS.

User error: Users cannot use <! -- an ISS to manage or keep track of personal/private email messages or message content

System error: An email server may fail to send or receive email messages with or without notifying email users

(Exception) Email servers will notify users if sent mail cannot be delivered

</Process


An Email system external to, or accessed from within, <! -- an ISS, and an Email client for reading, writing and sending Email content.



<Process-Identifier

Do User Messaging


<Narrative

<! -- Authors can request <! -- End-users to engage in sending and receiving message between one another in order to conduct a shared discussion or review of some designated content topic.

</Narrative




<People-Roles

<! -- End-users, <! -- Authors

</People-Roles

<Input-Objects

Messages (text), file attachments, messaging input submission selection commands (e.g., mouse clicks on button)

</Input-Objects

<Output-Objects

views (copies) of message content, file attachments in client display

</Output-Objects

<Process

<! -- Authors can request <! -- End-users in their courses to download or upload messages via a <! -- Asynchronous Messaging Systemor <! -- Synchronous Messaging System

<! -- Authors or <! -- End-users can download/upload messages for sharing with other <! -- End-users at any time.

(Exception) <! -- Authors can remove messages from their <! -- Asynchronous Messaging System

User error: Messages that are deleted from a <! -- Asynchronous Messaging System

cannot be retrieved

User error: <! -- Synchronous Messaging System message content is usually not saved by <! -- an ISS

System error: <! -- Asynchronous Messaging System message content managed by the <! -- an ISS may be lost if the <! -- an ISS Database is not backed-up.

</Process


Separate or embedded <! -- Asynchronous messaging system, <! -- Synchronous messaging system client (peer).



<Process-Identifier

Access other Web Content via <!-- an ISS


<Narrative

Any user of <! -- an ISS can navigate from managed content to access any Web content object through its Web Browser.

</Narrative




<People-Roles


</People-Roles

<Input-Objects

Web Browser navigation selection commands (e.g., mouse clicks on hyperlinked content objects).

</Input-Objects

<Output-Objects

Views (copies) of Web content objects, Applets downloaded into Web Browser

</Output-Objects

<Process

<! -- Authors can create content that contains Web hyperlinks

Any user of <! an ISS can select hyperlinked items within the content managed by <! -- an ISS to access objects on the Web

A selected item is downloaded into the User’s client if the Web server can retrieve the item.

(Exception) Users that select hyperlinked content will be disconnected from <! -- an ISS after a certain elapsed time, unless they return to <! -- an ISS

User error: <! -- an ISS will not allow access to <! -- an ISS managed content directly from the Web. Access to content within <! -- an ISS requires a user login.

System error: <! -- an ISS may unexpectedly terminate a user session if a user accesses Web items that attempt to upload information into <! -- an ISS, or launch applications unknown to <! -- an ISS.

</Process


Web (client) Browser, (Optional: Browser plug-ins and Helper applications), <! -- an ISS Web server



<Process-Identifier

Manage <! -- an ISS Content


<Narrative

<! -- IS Development Staff create, test, and modify (i.e., insert, update, delete) logical data models and physical data storage representations (e.g., Database schemas specified in SQL. Files and directories for organizing content stored in a networked file server) that other users employ to insert, update, delete, select or browse content of interest.

</Narrative




<People-Roles

<! -- IS Development Staff

</People-Roles

<Input-Objects

logical data models, physical data storage representations, repository source code, Web Server servlets (e.g., CGI programs or scripts), content test cases, and updates to same.

</Input-Objects

<Output-Objects

versions of <! -- an ISS content repository suitable for either further development, testing, production, or archiving; also result displays from content test cases or repository error messages.

</Output-Objects

<Process

<! -- IS System Developers create the representations, relations, and system components that provide users access to content managed by <! -- an ISS.

<! -- an ISS is used to organize, store, query, retrieve or update content that is managed by <! -- an ISS

<! -- an ISS uses a (relational) database management system to organize, query, retrieve or update content that is stored in its database

(Exception) <! -- an ISS stores data that identifies content, and controls access to content, stored as files in a networked file server, or as Web-based content accessed via the Web.

User error: <! -- an ISS cannot be used to store arbitrary files for end-users.

System error: <! -- an ISS cannot control updates to external content accessed via the Web.

</Process


<! -- an ISS content repository, including a Database Management System, Network File Server, and Web Server.



<Process-Identifier

Develop and Test <! -- an ISS


<Narrative

The <! -- an ISS <! -- IS development staff are responsible for developing, testing, and investigating reports of system anomalies from users of <! -- an ISS at <! -- Institution.

</Narrative




<People-Roles

<! -- IS Development Staff

</People-Roles

<Input-Objects

logical data models, physical data storage representations, <! -- an ISS application and repository source code, Web Server servlets (e.g., CGI programs or scripts), content test cases, Browser client Applets, and updates to same.

</Input-Objects

<Output-Objects

versions of all <! -- an ISS system components suitable for either further development, testing, production, or archiving; also result displays from content test cases or repository error messages.

</Output-Objects

<Process

<! -- IS System Developers create the representations that other users utilize to create,

insert, update or delete their content.

<! -- IS System Developers create, insert, update and delete content stored in <! -- an ISS representations to test its proper operations

(Exception) <! -- IS System Developers cannot guarantee that all functions supported by <! -- an ISS have been tested.

(Exception) <! -- IS System Developers cannot guarantee that all functions supported by <! -- an ISS are re-tested every time any <! -- an ISS function or operation is modified (updated).

User error: <! -- IS System Developers expect that users will notify them if users encounter anomalies in <! -- an ISS usage.

System error: <! -- an ISS system components may fail to operate correctly even though they have been tested.

</Process


Development, test, operational and archived versions of all <! -- an ISS system components; also all system development and testing tools available to the <! -- IS Development Staff.



ISS Process Hierarchy

Inputs for <! -- an ISS

Guidelines/Notes:

-- Identify type of Input as named objects (in boldface)

-- There are many types and kinds of information content managed by <! -- an ISS. I identify those Inputs/Outputs that I have created, used, or seen. Subsequently, there may be other Inputs/Outputs for <! -- an ISS that are unknown or unfamiliar to me, so let me know .

Learning Resources -- Syllabi, Case Studies, Research Papers, Business Plans, Exam Questions and Answers, and other kinds of learning content.

Career Resources -- Applications for advanced education programs, scheduled meetings

with industry executives, etc.

Resources for Sale -- Physical resources that people can negotiate the price, sell and buy.

Enterprise-specific resources -- Physical or informational objects/services (e.g., radiological images) that can be collected and managed by <! -- an ISS.

Messages -- <! -- End-Users and <! -- Authors can engage in asynchronous or synchronous communication through <! -- an ISS. Asynchronous messaging is supported through a service called, <! -- Asynchronous messaging system. The <! -- Asynchronous messaging system supports the upload, posting, and download/browsing of messages in the order they are received, along message threads. Synchronous messaging is supported through a <! -- Synchronous messaging system service similar to Internet Relay Chat.

<! -- End-User personal information -- <! -- End-Users can enter and update a designated set of personal information about them (e.g., enrollments, phone number, URL hyperlinks to personal Web pages) that is managed by <! -- an ISS. Items like personal web pages or work-related web pages are not stored within <! -- an ISS, but can be accessed on the Web via <! -- an ISS.

User navigation commands -- Users navigate through by selecting (e.g., "mouse-clicking") items visible as hyperlinks or pull-down selection menus displayed in client program's user interface.

<! -- ISS System Development Staff-only inputs -- <! -- an ISS developers can enter information that create, insert, update or delete schemas or content from the <! -- an ISS Repository, or its internal database. Similarly, they can create, insert, update or delete data entry forms (described in HTML or XML), data presentation displays (using one or more of Active Server Pages (ASP), HTML, XML, Javascript, etc.) visible through a client program user interface, or downloadable application programs ("applets"). Last, developers also input, upload and install application programs (e.g., Common Gateway Interface/CGI programs ("servlets") on the Apache Web server, SQL programs on the Repository database management system, and Java applets that are downloaded to a user client from the Web server on demand).

Any constraints ("pre-conditions") or business rules that specify or limit the range of acceptable or exceptional values of an object's attribute(s) before being accepted as input to a process or process step.

Outputs for <! -- an ISS

Guidelines/Notes:

-- Identify types of Output as named objects (in boldface)

View or copies of any Input object is generally available to users as Outputs, though

access may be restricted by user role.

Outputs are always formatted and presented in a manner that is consistent with the look-and-feel associated with <! -- an ISS, and its participation in reinforcing the <! -- Institution brand.

Any constraints ("post-conditions") or business rules that specify or limit the range of acceptable or exceptional values of an object's attribute(s) that may be exported to another program after processing.

Client program invocations -- <! -- an ISS can respond to a user input or navigational selection by invoking an application program on the user's computer. For example, <! -- Asynchronous messaging system, <! -- Synchronous messaging system, or applets can be invoked as outputs from <! -- an ISS.

Any program invocation may fail and produce an error message or failure signal. Thus anywhere a client-side program is invoked, an system error message/signal may be produced as output. For example, if an system error is detected, the process may need to only output the error message, rather than a potentially erroneous process output, so a post-condition may be used to check/prevent this.

<! -- an ISS Object Hierarchy

System components for <! -- an ISS

Guidelines/Notes:

-- Identify components as named objects (in boldface) and organize in a hierarchical abstraction.

-- We will limit our attention here to the main software components of the operational system. Software tools, programs or platforms employed to support ongoing development, testing and maintenance of <! -- an ISS are not included. Furthermore, there exists some hardware configuration that operates the <! -- an ISS server and content repository, but those are unknown to me, at this time. User clients generally operate on a user's PC, laptop, or workstation, whether running at home, work or at UCI.

-- Optional: a brief description of each component is included.

User Clients

Web browser -- generally Internet Explorer, Version 4.0 or later (there are some known usage bugs at present in using <! -- an ISS with either IE Version 5.0 and 5.5)

Browser plug-ins: perhaps the most common plug-in is that associated with the Adobe Acrobat .pdf file reader. When you download a Web object with a .pdf extension, it generally should invoke the Adobe Acrobat within your browser window.

External Helper Applications that are invoked by the Browser downloading of a registered MIME object type -- for example, if you access a Web object with the URL, http://www.ics.uci.edu/~wscacchi/SA/Requirements/RichPictures/Catalyst01.ppt note the object ends with a ".ppt" extension. On MS Windows-based Web Browsers, such an object triggers the browser to invoke an external program (the "helper" application) for which objects of this MIME type. "ppt" is usually registered to invoke the MS PowerPoint application, either within the browser window (when using Internet Explorer) or external to the browser (when using Netscape Navigator).

Applets: application programs that are stored on a Web server then downloaded and invoked when a user selects a content object via their client program (e.g., Web Browser) that requires the processing or results from a separate application program.

<! -- Synchronous messaging peers -- <! -- an ISS invokes a Internet Relay Chat (IRC) type of program (e.g., operating as an applet) that provides its own window user interface, outside of the Web browser. IRC, Jabber, AIM (AOL Instant Messaging) and Yahoo Messenger are among the various text-based Chat programs that are available. Other Chat programs like those from ThePalace.com offer 2D graphics and text chat, while those from Blaxxun.com offer 3D virtual reality-based Chat capabilities. Other peers may be used for multi-file transfer (e.g., via FTP), remote processor sharing, telnet, remote media stream services, etc.

<! -- Asynchronous messaging system -- <! -- an ISS allows users to select another known individual user or group identified (e.g., all <! -- End-Users registered in a <! -- Institution course) to send email. Once selected, <! -- an ISS can invoke the email program registered with the Web browser as the one to launch (invoke) to subsequently send/receive email. <! -- Asynchronous messaging system thus runs as in a separate window (aka, a "control thread"). <! -- an ISS does not directly import or manage user email messages.

Content Server

A Web Server (e.g., Apache, an open source web server available for use on Windows, Unix, Linux, MacOS, and other operating systems on networked computers), replies to requests from a user client for content through <! -- an ISS by accessing a content repository, or by accessing content external to <! -- an ISS via the Web. <! -- Institution <! -- IS development staff have custom-coded common gateway interface (CGI) programs that co-operate with Apache to determine whether to access the database manager within the Content Repository. Otherwise, the request goes to the Web for accessing remote Web content (e.g., following a URL hyperlink that displays the ISBN

http://www.ics.uci.edu/~wscacchi/SA/Requirements/RichPictures/Catalyst01.ppt

number for a textbook that in turn retrieves a Web page from amazon.com for the selected book). When <! -- an ISS retrieves content from the Web, it drops its connection to the user client. The user must then go back and refresh/reload the last page served by <! -- an ISS to resume their <! -- an ISS session. If a sufficient delay before refresh occurs, <! -- an ISS times out the connection to the user client, and must then establish a new user session with <! -- an ISS.

Application Servlets: these are often small application programs or Common Gateway Interface (CGI) scripts that encapsulate and invoke computational processing functions in external applications. These applications rely on servlets to provide transactions processing services between user (client) applications (e.g., Web Browser with content input forms) and the external application (e.g., a legacy DBMS application).

Local/Remote Search Engine: an application that indexes the content and location of every unique text word, graphic image, picture, sound file, digital video, etc. that is stored and managed by a local content server or accessible from the Web.

(Remote) Application Services: application services like those for merchant banking or credit card processing may be linked to servlets managed by <! -- an ISS. The Application Service Providers (ASPs) who offer these services are responsible for their ongoing development, enhancement, operation, and overall quality.

Content Repository

Database Management System: This repository encapsulates a SQL database when the primary content for courses and information about <! -- End-Users, <! -- Authors and staff is kept. An ER data model describes the database schemas that define and logically structure this content.

Network File Server: Exceptional or unusual content (e.g., large software application programs used in a class that must be downloaded by <! -- End-Users) are not necessarily stored within the database, but instead may be stored on a network file server that is visible only to the <! -- an ISS Content Server. Thus the content repository incorporates one/more databases, and one/more file systems (not including the Web or remote networked file servers).

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