18.8. GKS workstations and metafiles.   

A workstation is a very useful and important concept: GKS uses workstations for input and output. A workstation is:

a display plus a number of input devices attached to a single line or channel. Workstations have only a single display surface but may have any number of input devices.

There are three types of workstations:

INPUT only OUTPUT only OUTIN both input and output

The graphics manager will define the workstation types and numbers and provide a list similar to the table below to the GKS users at that installation.

A mechanism for long term storage of graphical information is the metafile. In GKS this important type of output device is given a special name - GKSM. The metafile is looked upon as just being another workstation - either INPUT or OUTPUT type.

Different formats for the metafile could be defined as different number workstations by the systems manager. This could cater for metafiles that are not produced by GKS but are common enough to warrant facilities for interpretation / creation of that format.

A GKSM stores type information, data record length information and then the data itself.

For more information see http://speckle.ncsl.nist.gov/~lsr/lsr.htm as well as
http://speckle.ncsl.nist.gov/~lsr/cgm.htm and http://speckle.ncsl.nist.gov/~lsr/cgm_std.htm

The ISO standard for CGM is available as well as other standards
concerned with graphics. 



 WS    WS         WS                                                         Device        Logical Devices

 Type  Category   Description                      Location                   Co-ordinates  Supported

 1     OUTIN      Storage Tube or raster look alike  Many located               1024x780      All

                  with use of keyboard input only.   around site

 2     OUTIN      Storage Tube with full use of      Many located               4096x3120     All

                  keyboard and thumbwheels.          around site

 3     OUTIN      Storage Tube with                 Two systems in             4096x3120     All

                  tablet attached.                  X Terminal Pool

 4     OUTIN      Vector refresh Display            Available at ABC locations  1024x1024     All

 5     OUTIN      Central Plotter                   Computer room              1000x5000     None

 6     OUTIN      Portable Pen Plotters             On loan from pool.          2000x2000     None

 7     INPUT      Digitisers                       Available at A and B        16384x16384   LOCATOR

                                                                                          CHOICE

                                                                                          STROKE

 8     OUTIN      Colour raster display             Location A only            512x512       All

 9     OUTIN      Vector Refresh                    Available at A and B        1024x1024     PICK

                                                  (used wth digitiser)                     VALUATOR

                                                                                          STRING