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<br />Three architectures for user interfaces for CRDSS were studied: command line
<br />user interfaces. fonns based user interfaces, and interactive graphics user
<br />interfaces. Table 7 contains brief descriptions of these various types of
<br />interfaces.
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<br />Table 7: User Interfaces: Alternative Architectures
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<br />Interface Description
<br />Type
<br />Command A command line interface requires using the keyboard to enter all requests for
<br />, LiRe.' action. Output is.generally te~luaI,in nature, although it is possible to request
<br /> the display of non-interactive images, Also, for these type of interfaces, a
<br /> high resolution. color monitor is not essential.
<br /> Typically there is no memory associated with each command. Thus, the
<br /> output of one command is not necessarily known by the subsequem
<br /> command, There are [WO methods that can be used to link commands, One
<br /> method is to use files for intermediate data storage, The other method is to
<br /> "pipe" the output from one command to the input for the next command, as
<br /> can be done using Unix,
<br /> An example of this type of interface is the Unix C-shell. In its basic form. all
<br /> commands are accomplished using the keyboard and output is sem 10 the
<br /> screen, redirected to a file, or piped to another command,
<br />Form A form based imerface requires the use of the keyboard to emer interactive
<br />8ased data into a form with fixed fields. A mouse is nOI necessary, aIlhough one may
<br /> be used, Also, a high resolution, color monilor is not essential, The fixed
<br /> fields used for data entry constrain what may be used as input Once data has
<br /> been entered imo these fields, a command may be invoked and output either
<br /> placed in the form, displayed on the terminal as graphics, or, perhaps, directed
<br /> to a file, To execute a series of commands. it may be necessary to use a series
<br /> of forms, each of which handles a ponion of the whole task to be
<br /> accomplished, Inter-form information may have to be explicitly saved to a file
<br /> or may be able to be saved in a temporary buffer between commands,
<br /> This type of interface does contain a state for the duration of a particular
<br /> form. Thus. the last inpulS emered into the form and the last OUtpUIS displayed
<br /> to the form will remain until overwritten or until another form is invoked,
<br />Inler- An interactive graphics imerface allows the user to use both keyboard and
<br />active mouse to accomplish actions, It is usually necessary to use a mouse with these
<br />Graphics types of imerfaces and a high resolution monitor is desirable, if not necessary,
<br /> for much of the required functionality,
<br /> This type of imerface may also use forms and even some command line
<br /> syntax, although these will be used in the context of a direct manipulation,
<br /> probably window based, imerface. Commands are typically executed using
<br /> pull-down menus, push bunons. lislS and text fields. Graphics are used in this
<br /> type of interface and. using the mouse, can be used as both input and output,
<br /> For instance, an object may selected off an image using the mouse and the
<br /> image can be subsequently updated to reftect this selection,
<br /> 1lKs tYll",utin&edace.provides the most ftel<ibility of,thethree,and.contains,
<br /> the currem state of the model for the duration of the run, Often this state is
<br /> represenled both textually and graphically,
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<br />User Interfaces:_
<br />Evaluating.
<br />Architectures
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<br />DAMES& M OORE/CADSWES-43
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