Octagon PC-500, Руководство пользователя

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B-5
PC-500 user’s manual Software utilities
Remarks
The HIMEM driver can be used to allow ROM-DOS to run in High
Memory.
HIMEM supports a default of 32 handles.
HIMEM should not be used with older versions of VDISK. Current
versions of VDISK will use XMS memory if it is available.
HIMEM recognizes PS/2 style machines A20 line control. HIMEM
determines whether to use the PS/2 A20 control or the AT A20 control
method automatically by calling INT 15h, function C0h (get system
configuration).
The automatic detection can be overridden with the "/Machine:n" com-
mand line switch. Replacing "n" with 1 designates the PC AT A20
control method. Replacing "n" with 2 designates the PS/2 method.
Example 1
DEVICE=HIMEM.SYS
The above command installs the XMS device driver. Once this driver is
installed, accessing the HMA and Extended Memory (XMS) areas are
legal. The Extended Memory area can contain up to 2 Gigabytes of
memory. Typical systems have 4, 8, or 16 MB XMS memory installed.
Example 2
DEVICE=HIMEM.SYS /machine:1
This example forces the use of the AT style A20 line control.
The HIMEM driver will fail to load if either the machine does not have
memory above the 1 MB boundary or the BIOS does not provide support
for it. It will also fail to load if another XMS manager has been in-
stalled previously.
≡
I17HNDLR.EXE
Purpose
This support command allows the system to use the INT 17 functions
when the extended BIOS area is disabled (i.e., W2[9-10] is not jum-
pered) or when it is reprogrammed with another BIOS.