[comp.windows.x] History of DIX/DDX/OS partitioning in the X server

trm@cbnews.ATT.COM (Tom R. Mueller) (12/15/88)

The X server is a successful example of achieving software reuse by 
partitioning the software into layers, one of which is completely
portable because it is machine independent and others that must be
modified when porting to a new architecture.  

I'm curious about the development process by which this partitioning
came about.  When was the functionality within the server separated
into layers?  Before or after the first server was implemented?  Was
the partitioning based on the implementations of other window
systems?  What criteria are used to determine the layer for a piece of
functionality?  When were these criteria developed?  Was any formal
mechanism used to do the partitioning?  If the development was done
again, what would be done differently?

The layered architecture of the X server can be used as a model for
other software systems that need to be ported to a variety of
environments.  Any insights obtained through the development of the
X server may be useful to many software developers.

- Tom Mueller			CB 0D109
  (1-614-860 | 8-353) 5287	6200 E. Broad Street
  ...att!cblpn!trm		Columbus, OH 43213

-- 
- Tom Mueller			
  (1-614-860 | 8-353) 5287
  cblpn!trm
  CB 0D109