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 Extended Memory
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     The CA-Clipper/ExoSpace program, EXOSPACE.EXE, as well as applications
     linked with CA-Clipper/ExoSpace, require extended memory while running.
     Extended memory is memory addressed by the CPU above 1 MB.

     CA-Clipper/ExoSpace does not work with EMS, as defined by the
     Lotus/Intel/Microsoft bank-switching scheme, although it can use memory
     managed by products that use the 386 VCPI standard, as described below.

     In its default configuration, the CA-Clipper/ExoSpace loader utilizes
     about 90 KB, 18 KB of which is in low memory.  Under a VCPI host, the
     VCPI page tables are also stored in low memory, adding about 15 KB to
     the low memory footprint.  Under DOS DPMI, the stack is also locked in
     low memory.  Under some circumstances, you can reduce the amount of
     memory that CA-Clipper/ExoSpace requires.

     In most cases, no special action needs to be taken to make extended
     memory available to CA-Clipper/ExoSpace.  However, to ensure that
     CA-Clipper/ExoSpace and applications linked with CA-Clipper/ExoSpace are
     running optimally, you may wish to ensure that enough extended memory is
     available.

     If you are running MS-DOS Version 5 or later, you can execute the MEM
     command to find out how much conventional and extended memory is
     available.  If you are using another DOS, you may be able to obtain this
     information from a similar utility.

     Two items listed by the MS-DOS MEM command are important to
     CA-Clipper/ExoSpace:  "available contiguous extended memory" and
     "available XMS memory."  Depending on your machine's configuration, one
     of these items may be missing or its value may be zero, but as long as
     one of the two items has a value of 1 MB or greater, you should be able
     to run CA-Clipper/ExoSpace and CA-Clipper/ExoSpace applications
     successfully.

     If neither of these items are listed when you execute MEM, or their
     values are both zero or less than 1 MB, you may need to change the
     machine's configuration in some way, perhaps by installing more extended
     memory, or by reducing the amount of memory allocated to any other
     resources that utilize XMS.

     In general, the manner in which a machine is configured via CONFIG.SYS
     should not be of concern, as long as enough extended memory is
     available.  Software drivers for extended and expanded memory are
     described in the following section.

 Extended Memory Protocols

     CA-Clipper/ExoSpace works with the following protocols that use extended
     memory:

     .  DOS Protected-Mode Interface (DPMI)

     .  Virtual Control Program Interface (VCPI)

     .  Extended Memory Standard (XMS)

     The following table shows examples of products that use these protocols
     and lists the versions that CA-Clipper/ExoSpace works with:

     ------------------------------------------------------------------------
     Protocol    Products                        Versions
     ------------------------------------------------------------------------
     DPMI        Microsoft Windows, 386          3.0 and later
                 Enhanced mode
                 OS/2 Virtual DOS Machine        2.0 and later
     VCPI        QEMM                            4.1 and later
                 EMM386                          MS-DOS 5 or
                                                 MS-Windows 3.1
                                                 and later
                 386MAX                          4.01, 4.02, 4.06
                                                 and later
     XMS         HIMEM.SYS                       2.10 and later
     ------------------------------------------------------------------------

     When your CA-Clipper/ExoSpace application starts up, CA-Clipper/ExoSpace
     searches the environment for memory managers, in the order listed below.
     In most cases, CA-Clipper/ExoSpace uses the first memory manager that it
     finds:

     1. A previously-loaded CA-Clipper/ExoSpace program with a non-private
        memory pool

        If it finds a loaded CA-Clipper/ExoSpace application, the application
        uses the same memory pool as the first application.  (You can create
        CA-Clipper/ExoSpace programs that use private memory; this private
        memory will not be available to subsequently loaded
        CA-Clipper/ExoSpace applications.)

        If a previous loaded CA-Clipper/ExoSpace application is not found, it
        continues searching.

     2. A DPMI host

        If CA-Clipper/ExoSpace finds a DPMI host, it follows the DPMI
        protocol.  The DPMI host manages memory.

        If it does not find a DPMI host, it continues searching.

     3. A VCPI host

        If CA-Clipper/ExoSpace finds a VCPI host, it follows the VCPI
        protocol.  It also searches for an XMS driver.

     4. An XMS driver

        If CA-Clipper/ExoSpace finds an XMS driver, it follows the XMS
        protocol to allocate memory from the XMS pool.  If both a VCPI host
        and an XMS driver are found, it allocates memory from the XMS pool
        and from the VCPI pool.

        With VCPI only, the VCPI protocol is followed.  With XMS only, the
        XMS protocol for allocating memory is followed.

     If CA-Clipper/ExoSpace does not find any memory managers that use one of
     these protocols, it uses BIOS Interrupt 15h, function 88h on ATs and
     compatibles to determine how much memory is available to it.  On other
     non-AT-compatible machines, your users must use the DOS16M environment
     variable to specify the exact extended memory range.

     Except under VCPI and DPMI, CA-Clipper/ExoSpace allocates all available
     memory, unless you restrict the amount of memory your program can
     utilize.

     Device drivers that allocate their memory from a DPMI, VCPI, or XMS pool
     pose no problems for CA-Clipper/ExoSpace.  In addition,
     CA-Clipper/ExoSpace works with the following device drivers, even when
     they do not allocate memory from a standard memory manager:

     ------------------------------------------------------------------------
     Device Driver                     Versions
     ------------------------------------------------------------------------
     RAMDRIVE.SYS                      2.0 and later
     SMARTDRIVE.SYS                    2.0 and later
     VDISK.SYS                         All IBM versions
     ------------------------------------------------------------------------

     Other application programs, device drivers, or TSRs (like disk caches)
     that do not use DPMI, VCPI, XMS, or Interrupt 15h, function 88 for
     managing extended memory will not work with CA-Clipper/ExoSpace programs
     if they start before CA-Clipper/ExoSpace.

     CA-Clipper/ExoSpace applications will work under environments such as
     Windows (including Windows 3.0 or later in enhanced mode), Carousel,
     DoubleDOS, DESQview, and others.