DC>
  > This doesn't have to do with programming for OS/2 but it is about the
  > programming of OS/2.  I have read that OS/2 creates virtual
  > machines each with
  > 4GB of memory. One for OS/2 programs and one for Win progs.
  > That might not be right, so please correct me.
DC>

  Each Intel OS/2 process has a linear address space (read up on the
  linear addressing scheme of the 386 if you don't know what this is) of
  512Mb. Intel OS/2 processes run (in ring 3) with segmentation
  effectively disabled (DS=ES=SS) using the 32-bit near addressing mode
  of the 16:32 scheme.

  ( The Intel OS/2 kernel uses the 48-bit (16:32) and 32-bit (16:16) far
    addressing modes, but those are invisible to applications
    programmers. )

  Each Virtual DOS Machine is effectively just another Intel OS/2
  process, and has the same 512Mb linear address space.  However VDMs
  run in v8086 protected mode, meaning that segmentation is fixed to
  address the first 1Mb of linear memory.  The Intel OS/2 kernel
  supplies DPMI services to allow VDMs to use true protected mode and
  access the linear address space above the 1Mb line.

  Read the _Technical_Concepts_ section of the OS2DOS Frequently Given
  Answers for more information on Intel OS/2 VDMs.

  Of course, the scheme for PowerPC OS/2 is different.

  > JdeBP <
 > Run, do not walk, to your nearest FIDONET files site for FGA-OS2D.ZIP, <
 > the Frequently Given Answers from the OS2DOS echo.  If there is no     <
 > Fernwood filebone site near you, you can also FREQ it from 2:440/4.0 . <
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