Lab 4-4 MEMORY MANAGEMENT IN DOS
Objective
The objective of this lab is to make you familiar with some common methods of memory management available in DOS. After completing this lab exercise, you will be able to:
_ Load TSRs from AUTOEXEC.BAT.
_ Use the MEM command to view your workstation’s current memory configuration.
ACTIVITY
Loading a TSR high
1. Allow your lab workstation to boot to DOS.
2. Insert the TSR disk provided by your instructor. The program is called addit.
3. Use the COPY command to copy the TSR and all related files from the disk to the root directory of your lab workstation.
4. Make C:\ your current directory. What is the name of the TSR you just copied over? ____________________
5. Type EDIT AUTOEXEC.BAT and press Enter.
6. Add the following to your AUTOEXEC.BAT file: LH C:\tsr.tsr. (Note: The TSR.TSR should be replaced with the name of the TSR on the disk.)
7. Press the Alt key.
8. Use the down arrow [↓] to select Save from the File menu.
9. Press the Alt key.
10. Use the down arrow [↓] to select Exit from the File menu.
11. Reboot your lab workstation.
12. To verify that the TSR loaded, attempt to use its function.
Using the MEM command
1. Allow your lab workstation to boot to DOS.
2. Type MEM at
the command prompt and press Enter.
3. Compare the information provided by the MEM command to Table 4-1.
Table
4-1
Microsoft
Windows 95 and Windows 98 example
|
Memory
Type |
Total |
Used |
Free |
|
--------------- |
------ |
------ |
----- |
|
Conventional |
640k |
52k |
588k |
|
Upper |
0k |
0k |
0k |
|
Reserved |
384k |
384k |
0k |
|
Extended
(XMS) |
31,744k |
168k |
31,576k |
|
--------------- |
------ |
------ |
------ |
|
Total
memory |
31,768k |
168k |
31,576k |
|
|
|
|
|
|
Total
under 1 MB |
640k |
52k |
588k |
Total Expanded
(EMS)
32M (33,046,528 bytes)
Free Expanded (
Largest
executable program size 588K (602,512
bytes)
Largest free upper memory block
0K (0 bytes)
MS-DOS is resident in the high memory area.
Windows
2000 and Windows XP example
655360 bytes total conventional memory
655360 bytes available to MS-DOS
633872 largest executable program size
1048576 bytes total contiguous extended
memory
0 bytes available contiguous extended memory
941056 bytes available XMS memory
MS-DOS resident in High Memory Area
mem /f - This would
display the amount of conventional memory free.
Review Questions
Circle True or False.
1. TSR stands for terminate safety return. True / False
2. TSRs are programs that stay in memory even when they are not being used. True / False
3. TSRs can be loaded into memory only via the CONFIG.SYS. True / False
4. You can use the MEM command to view the amount of available hard drive space.
1. True / False
5. The HIMEM.SYS file is used primarily to test conventional memory. True / False
6. If the following line were added to your AUTOEXEC.BAT file, what would it tell your computer to do?
LH c:\myfile
Lab Notes
What is a TSR?—A TSR is any program or device driver that resides in memory even though it is not active. TSR stands for terminate and stay resident.
What is HIMEM.SYS?—HIMEM.SYS is a device driver used to manage expanded memory in the DOS environment. If HIMEM.SYS fails to load, reboot the PC and check your CONFIG.SYS to verify that the path is specified correctly.