Extended Memory; Expanded Memory; High Memory Area (Hma - Intermec Janus 2020 User Manual

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Reader Specifications

Extended Memory

The reader is initially configured with 64K of extended memory available,
which is allocated for use by Intermec applications (IC.EXE and IRL). To
remove the RAM drive and use the available extended memory, you need to
change or delete the SRAMDISK statement in the CONFIG.SYS file. You can
also use extended memory for overlay memory.
The reader provides extended memory for control and access to RAM above
1MB. The extended memory conforms to XMS specification 2.0. Extended
memory is initialized and managed by the HIMEM.SYS driver. HIMEM.SYS
looks at all the memory in the system and takes control of everything above
1024K. You must load all drivers in extended memory through the
HIMEM.SYS interface. If a driver is not compatible with HIMEM.SYS, you
cannot load it.
Some applications may require you to exclude memory from HIMEM.SYS
management, leaving some extended memory available. If this is necessary,
you should reconfigure the RAM drive (E) to use the available extended
memory. DOS drivers must check in with HIMEM.SYS for their memory
assignments within the XMS managed by HIMEM.SYS. Currently, the RAM
drive uses the XMS interface through HIMEM.SYS.

Expanded Memory

Once more than 1MB of memory is installed on a PC, it can be used as
expanded memory and is a way for the system to access memory beyond the
1MB barrier. To use expanded memory on a PC, you need an expanded
memory board and an expanded memory manager.
Expanded memory is not available on the JANUS reader.

High Memory Area (HMA)

The high memory area (HMA) is a 64K block of memory, starting 16 bytes
below the 1024K mark, and is the first 64K of extended memory.
Since HMA can only hold one item, the first program that requests HMA uses
it, regardless of the size of the program. You cannot use the statement
DOS=HIGH on the reader because DOS already resides in ROM in an upper
memory block.
Note: The HMA is used by Reader Services. If HIMEM.SYS is not loaded or if HMA
is being used by another driver, Reader Services is not loaded and the JANUS 2020
does not function as a bar code reader.
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