The
process of memory
optimization
is an archaic way of saving several KB’s of memory within a system that has a
maximum of 1MB of RAM
Despite
advancements in hardware technology and the total memory
limitations
being increased to 16MB and above, DOS
could
only support 1 MB
of
RAM
for
backwards compatibility purposes.
All
programs
inside
DOS
must
be run in conventional memory
Since
the DOS
operating
system
also
runs in the conventional memory
, it drains the conventional memory
of space for applications
In
order for DOS
to
maximize the total amount of conventional memory
to
be used by applications
, it must reduce its load on the
conventional memory
As you can see the
memory
0KB to 640KB is defined as
conventional memory
and is designed to hold DOS
and all DOS applications
by default. The reserved region of
the memory is between 640KB to 1024KB.This region is segmented in to 64KB
sections designed to run as shadow RAM
for all devices
installed on the system such as the
BIOS
, VGA
card, etc.
Extended
and
Expanded memory
Extended
memory
is all the memory above 1MB and can
be activated with the HIMEM
.SYS
program. Expanded memory
is all the memory above 640KB and
can be activated with the EMM386.EXE
program. EMM386.EXE can only
activate if the HIMEM.SYS program is activated prior.
–Shifting
the Terminate and Stay Resident (TSR’s
) programs
from
the conventional memory
to
the Upper Memory Blocks (UMB
).
–Shifting
the transient components of the MSDOS.SYS
file
to the High Memory Area (HMA
).
Expanded memory
is no longer required for most DOS
programs
. However we need emm386.exe in a limited capacity to deal with Terminate and
Stay Resident TSR’s
programs. TSR’s are programs of
DOS that remain in the RAM
after being run and do not release
the memory until the computer has been rebooted. We can limit emm386.exe to
extend from 640KB to 1MB by using the NOEMS
option of emm386.exe. These changes
must be made to the file CONFIG.SYS
.
Config.sys
Device
= C:\Dos\HIMEM.SYS
Device
= C:\Dos\EMM386.EXE noems
DOS=UMB
By using the
command DOS
=UMB
in the Config.sys
file, we are preparing the empty
spaces in the reserved memory
block for TSR’s
.
We can shift the
DOS
TSR’s
from the conventional memory
to the Upper Memory Blocks (UMB
) by using the Devicehigh
command in the config.sys file. You
could also use the Loadhigh
or LH command in the autoexec.bat
file to perform the same task.
By using the DOS
=high command inside the config.sys file to shift the transient components of
DOS to the High Memory Area (HMA
). The resident components of the DOS operating system
will remain in the Conventional
Memory.
Terminate
and Stay Resident (TSR) is a program that remains in memory
once
loaded
High
Memory Area (HMA
) the first 64KB of RAM
above
1MB
Resident
Dos programs
are
the components of Dos that must remain in memory
above
0KB
Transient
Dos programs
can
be shifted to the HMA
by
the command DOS
=HIGH
MEMMAKER.EXE
is
a program of DOS
designed to automate the
process of memory
optimization.
It
asks a series of questions from the user and makes the according amendments in
the CONFIG.SYS
and
AUTOEXEC.BAT
file
for the system memory
to
be optimized inside DOS
You
can use the command MEM /c to view your systems current memory
distribution.
-
Which region in the memory
map is the Extended
memory?
-
Which region in the memory
map is the Expanded memory
?
-
Which region in the memory
map is the HMA
memory?
-
Which region in the memory
map is the reserved memory?
-
Which region in the memory
map is the Conventional memory?
-
Which region in the memory
map is the UMB
memory?
-
Which region in the memory
map is the shadow RAM
?
-
Which region in the memory
map are all DOS
programs
run by default?
-
How large is the conventional
memory
-
640KB
-
1024KB
-
384KB
-
64KB
-
16MB
-
How large is the reserved memory
-
640KB
-
1024KB
-
384KB
-
64KB
-
16MB
-
How large is the HMA
memory
-
640KB
-
1024KB
-
384KB
-
64KB
-
16MB
-
What memory
size will extended memory extend
to in a 80286 system
-
640KB
-
1024KB
-
384KB
-
64KB
-
16MB
-
What file will activate the
extended memory
-
EMM386.EXE
-
HIMEM
.SYS
-
TSR
-
Memory.com
-
What file will activate the
expanded memory
-
EMM386.EXE
-
HIMEM
.SYS
-
TSR
-
CONFIG.SYS
-
What file will contain all memory
optimization information
-
EMM386.EXE
-
HIMEM
.SYS
-
TSR
-
CONFIG.SYS
Answers
-
A
-
B
-
C
-
E
-
D
-
E
-
E
-
D
-
A
-
C
-
D
-
E
-
B
-
A
-
D
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