1 karl  1.1.2.1 Title: Building Pegasus for Embedded Systems
  2               Date: 1 November 2007
  3               Status: Draft
  4               

  5 karl  1.1.2.2 Overview
  6                   There are some signnificant differences between implementing
  7                   Pegasus for an embedded system with limited resources and for a
  8                   general purpose server or client platform.  Typically the
  9                   differences are:
 10               
 11                   1. The whole build process is different in that the server is
 12                   built on a host system for a different target system.
 13               
 14                   2. The sofware resources such as shells, etc. are significantly
 15                   limited in the target platform.
 16               
 17                   3. Memory resources are often severly limited and with absolute
 18                   limits without swap space, etc.
 19               
 20                   4. The platform is often completely defined before installation
 21                   with no capabilities for extension (new providers, etc.) and
 22                   minimal capabilities for change of functionality and
 23                   parameterization.
 24               
 25                   Therefore, to enable improved use on these platforms Pegasus has
 26 karl  1.1.2.2     been modified with a number of options that we hope will help
 27                   embedded system implementors create more effective
 28                   implementations.
 29               
 30                   NOTE: Today this has been designed around the usage in the VxWorks
 31                   platform but much of this functionality is considered general.
 32               
 33                   The major area of effort include:
 34               
 35                   1. Separate of the server and client builds
 36               
 37                   2. Building the complete Pegasus application as a single image. 
 38                       a. Move from dynamic library build to static build
 39                       b. Add concept of static providers (Providers linked with the
 40                       server)
 41                       c. Add concept of memory-resident repository.
 42                       d. Limit the capability to modify parameters and provide for
 43                       parameter setup as part of server start. (NOT DONE YET)
 44                       e. Set limits on memory usage and control memory usage (NOT
 45                       DONE YET)
 46               
 47 karl  1.1.2.2     3. Removing server functionality not required for the embedded server.
 48               
 49                   The following sections define several particular components of
 50                   functionality and the build process particular to embedded
 51                   systems.

 52 karl  1.1.2.1 
 53               Separation of the server and client builds
 54               

 55 karl  1.1.2.2     When building for embedded systems typically the server is built targeted
 56                   to one platform and the clients and support tools are build targeted to
 57                   another (host) platform.  Thus, for example, for VxWorks, the cim server
 58                   would be targeted to the target VxWorks platform and the remiaining
 59                   components of Pegasus (clients, compiler, end-end tests) would be
 60                   targeted towards the development system.
 61               
 62                   The Pegasus build environment has been extended to make this possible.  
 63                   The user may elect to work from either a single source tree or multiple
 64                   source trees. But in any case, two separate build sequences are required
 65                   for a complete Pegasus build, the target platform build (cross compile)
 66                   of the cimserver and server unit tests and the host build.  The sections
 67                   below describe these processes.
 68               
 69                   Note that this work has expanded the make structure of pegasus to include
 70                   a new make configuration file (config.mak) located in the PEGASUS_ROOT
 71                   directory. If this file exists, the definitions included in the file are
 72                   included in the mak/configure.mak file which means that this file
 73                   can be used to setup configuration parameters for the make.  The 
 74                   host and target make structure uses this new file.

 75 karl  1.1.2.1 
 76               
 77               Building the server for the target platform
 78               

 79 karl  1.1.2.2     1. Set up a configure.mak in the pegasus source root directory with the
 80                      specific directives for the target make.  Note that there are several
 81                      sample configure.mak files defined in the pegasus.vxworks directory.
 82                      Since there may be a number of variations of the make structure 
 83                      depending on the test configuraiton, it is logical to set up a
 84                      configure.mak for each and simply copy or softlink the correct one
 85                      into the pegasus source root.
 86                      NOTE: There are several sample configure.mak files in the
 87                      direcotry pegasus/vxworks/configuration each named for the
 88                      appropriate vxworks target

 89 karl  1.1.2.1 

 90 karl  1.1.2.2     2. Execute the Make to build the server image

 91 karl  1.1.2.1 
 92               

 93 karl  1.1.2.2     TBD: Note that this new procedure has not yet been tested

 94 karl  1.1.2.1 
 95               Building the clients on the host platform
 96               

 97 karl  1.1.2.2     The host platform build is the same as as any normal pegasus build.  
 98                   It is initiated through the top level make file and builds all 
 99                   components of the envrionment for execution on the host system.
100                   Typically this can be executed with the alternatives defined below.

101 karl  1.1.2.1 
102                   make new world    -- builds everything
103                   make              -- build the source
104                   make repository   -- builds the repository for the host system.
105               

106 karl  1.1.2.2     There is no specific make today to simply build the non-server components.

107 karl  1.1.2.1 

108 karl  1.1.2.2     NOTE: The $PEGASUS_ROOT/configure.mak is normally used to set up the 
109                   configuration for the target build.   It need not be used for the host
110                   build.  It can be used to generate parameters for this build

111 karl  1.1.2.1 
112               
113               Special characteristics of the Embedded OpenPegasus Server
114               

115 karl  1.1.2.2     OpenPegasus implemented several special characteristics to support
116                   embedded platforms including:

117 karl  1.1.2.1 

118 karl  1.1.2.2     1. Memory-Resident Repository (PEP 307)
119                   2. Static providers (PEP 309)
120                   3. Single image build that produces a single output file containing
121                      the server, providers, and the memory-resident class repository.
122               
123                   This section provides an overview of how to create a complete embedded
124                   server.
125               
126                   Note that there is a working example in the directory vxWorks/cimserver of
127                   a build with some sample providers and a complete class repository 
128                   containing 3 namespaces.

129 karl  1.1.2.1 
130               Building the Memory-Resident Repository
131               

132 karl  1.1.2.2     See the note readme.MemoryResidentRepository file for detailed 
133                   information on the memory-resident repository

134 karl  1.1.2.1 
135               Building Providers
136               

137 karl  1.1.2.2     See the note readme.StaticProviders for detailed information on building
138                   static providers for OpenPegasus embedded systems.

139 karl  1.1.2.1 
140               
141