FDXMS Ü
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Manages the use of extended memory.
FDXMS.SYS manages programs' use of extended memory and of the high memory
area (HMA). This prevents programs from simultaneously using the same
area of memory. You install the FDXMS.SYS device driver by adding a
device command for FDXMS.SYS must precede any device command for programs
or device drivers that use extended memory.
Syntax: DEVICE=[drive:][path]fdxms.sys [/hmamin=m] [/numhandles=n]
[/int15=xxx] [/a20control:on|off]
[/shadowram:on|off] [/cpulock:on|off]
[drive:][path]
Specifies the location of the FDXMS.SYS file.
/hmamin=m
Specifies the amount of memory (in kilobytes) a program must use
before FDXMS.SYS permits the program to use the high memory area.
Valid values for m are 0-63. The default value is 0.
/numhandles=n
Specifies the maximum number of extended-memory-block (EMB) handles
that can be used simultaneously. Valid values for n are 1-128. The
default value is 32. Each additional handle requires an additional
6 bytes of resident memory.
/int15=xxx
Allocates the specified amount of extended memory (in kilobytes) for
the Interrupt 15h interface. Some older programs use a conflicting
extended-memory scheme. To ensure enough memory is available, add
64 to the value you want to specify for xxx. Valid values for xxx
are 64-65535. If you specify a value that is less than 64, the
value becomes 0. The default value is 0.
/a20control:on|off
Specifies whether FDXMS.SYS is to take control of the A20 line even
if A20 was on when FDXMS.SYS was loaded. If you specify
/a20control:off, FDXMS.SYS takes control of the A20 line only
if A20 was off when FDXMS.SYS was loaded. The default setting
is /a20control:on.
/shadowram:on|off
Specifies whether FDXMS.SYS is to switch off shadow RAM - Random
Access Memory (RAM) used for read-only memory (ROM) - and add that
RAM to its memory pool. If your computer has less than 2 megabytes
of RAM, the default setting is /shadowram:off. This
parameter is supported only on some computers.
/cpulock:on|off
Specifies whether FDXMS.SYS is to affect the clock speed of your
computer. If your computer's speed changes when you install
FDXMS.SYS, specifying the /cpulock:on might correct the problem.
Enabling this switch slows down FDXMS.SYS.
Example:
To install FDXMS.SYS, using the default values, add the following line
to your CONFIG.SYS file: device=fdxms.sys
Since no location is specified, FreeDOS searches for FDXMS.SYS in the
root directory of your startup drive.