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Document 1302
Troubleshooting

Initials:
        11/26/91
    DRDOS 6.0

Description:

 Troubleshooting

Isolating the Problem

If you encounter memory conflicts after you have arranged your device
drivers and TSRs in the manner described in the previous chapter,
your next step should be to isolate and identify the offending conflict.
The best way to do this is to methodically load each of your drivers,
TSRs, and application programs one at a time until you encounter the
problem driver or program.

Note:
To complete the following steps, you should be familiar
with editing your config.sys and autoexec.bat files with a wordprocessor
or text editor such as the DR DOS EDITOR, and with the REM command.
Refer to Chapters 7 and 11 of the DR DOS 6.0 User Guide.

Whenever you experiment with and change your config.sys and autoexec.bat
files, you should always have a separate bootable floppy disk
available containing the unedited, original versions of your config.sys
and autoexec.bat files in case you need to reboot your computer
from the A: drive. Then, if you need to go back to your original
configuration, you can copy the original config.sys and autoexec.bat files
from your backup diskettes onto your boot disk. (See Chapter 10 in the
DR DOS 6.0 User Guide for information on how to create a bootable
floppy disk.)

To isolate the source of your memory conflict, turn off those lines
in your config.sys or autoexec.bat file that might be causing
the problem.  Do this by editing the config.sys or autoexec.bat
file and placing a REM comment at the beginning of each line you want
to turn off. For example, to turn off the following config.sys line:

DEVICE = C:\DRDOS\EMM386.SYS /F=AUTO /K=2024

add the REM comment to the beginning of the line:

REM DEVICE = C:\DRDOS\EMM386.SYS /F=AUTO /K=2024

If you find a particular line is not causing a problem, you can reactivate
it by simply removing the REM statement.

Note:
You can also use the DR DOS conditional "?" statement
to activate/deactivate config.sys line commands. See Chapter 11
of the DR DOS 6.0 User Guide for details. If you use this option,
make careful note of whether you said "yes" or "no" to loading each line.

After turning off the suspect lines with a REM statement, reboot your
computer to retest the driver/application with which you first encountered
your memory problem. If the system runs correctly, reenter your config.sys
or autoexec.bat file and remove the REM command from one line and
then reboot and reload the application. Continue this process until
you again encounter the memory problem. When it recurs, you will have
isolated the line in the config.sys or autoexec.bat file that
is causing the memory conflict.  You can now take action to resolve
the conflict, as described in the following sections.

Possible Problems

After you have isolated the problem driver or program, you can use
the techniques described below to make the appropriate corrections
to your computer's configuration.

Some problems that you might encounter after installing the MemoryMAX
drivers include:

Insufficient conventional memory to load a particular driver
or program

HILOAD, HIINSTALL, or HIDEVICE features do not seem to operate
correctly

Computer locks up

Upper memory conflicts

Video problems

Error message: "Packed file is corrupt."

Each of these problems, and the techniques to correct them, are described
below.

Insufficient Conventional Memory

After using the DR DOS 6.0 memory management system to increase conventional
memory, there should not be a problem due to insufficient memory.  However,
if a large number of device drivers or TSRs are in use, this problem
might still occur.  Review Chapter 1 of this guide to ensure you have
taken the proper steps to optimize system memory.

Try the MEMMAX +L command in case an earlier command or batch file
disabled available low memory.  Finally, if the application does not
use the graphics display area, try the /V switch of the DR DOS 6.0
memory manager, followed by MEMMAX +V before loading your application.

HILOAD, HIINSTALL, or HIDEVICE Considerations

Each of these commands requires the availability of upper memory blocks
(UMBs). You can verify that the UMBs are available by using the DR
DOS MEM /B or /U commands to see a report of your memory usage (see
Chapter 10 of the DR DOS 6.0 User Guide for a full description
of the MEM command). Available UMB blocks will be marked as FREE
under the Type column in the MEM listing.

The HILOAD, HIINSTALL, and HIDEVICE commands require prior installation
of the EMM386.SYS or HIDOS.SYS driver. If the MEM report shows that
upper memory is not being utilized, check your config.sys to make
sure the driver has been properly installed and that the option switches
have been entered correctly. If they are set, pay particular attention
to the /FRAME, /AUTOSCAN, /INCLUDE, /BDOS, and /EXCLUDE switches to
ensure that any upper memory address specified by these switches have
been correctly set (a common error is using an "oh" instead
of a zero).

If you use Microsoft Windows 3.0, the /WINSTD switch might
have been set. The /WINSTD switch automatically blocks access to the
UMBs, making them unavailable to HILOAD, HIINSTALL, and HIDEVICE.
Windows 3.0 will not run properly in standard mode if UMBs have been
used by something else. (See the "Using EMM386.SYS with Windows"
on page 22.)

If you do not require the use of expanded memory, set the /FRAME switch
to /FRAME=NONE.

The HILOAD command must be invoked before using the MEMMAX
-U command to disable upper memory. Use the MEMMAX +U command to re-enable
upper memory, if necessary. (Note that the DR DOS installation program
automatically inserts the MEMMAX -U command in the autoexec.bat
file; therefore, you must either put HILOAD above it, or use MEMMAX
+U to enable upper memory).

If there appears to be sufficient upper memory available, but HILOAD,
HIINSTALL, or HIDEVICE fail to put a particular TSR or driver into
upper memory, some device drivers and TSR programs when initializing
might actually expand and take up considerably more RAM than they
will ultimately need. See "System Memory Optimization" on
page 9 for a complete description of this problem.

Computer will not boot or locks up

Reboot your machine with a bootable floppy disk in drive A:. Follow
the instructions in "Isolating the Problem" above and edit
the C: drive config.sys and/or autoexec.bat files to turn off
and isolate, with the REM command, those lines in the files that might
be causing the problem.

The most probable cause is that the DR DOS 6.0 memory manager has
moved something into a region of upper memory required by a hardware
device driver attempting to use the same areas of memory.  Use the
/EXCLUDE option (see page 18) switches to remedy the
problem.

If a hardware device is not causing a conflict, and the lockup occurs
with a particular program, this program might become confused when
upper or low memory is available. Try using the command MEMMAX -U
and/or MEMMAX -L before loading the program.

Upper Memory Conflicts: Using /EXCLUDE

Your machine or the accessories in your machine might be using upper
memory addresses that are also being accessed by the DR DOS 6.0 memory
manager. To prevent this, exclude EMM386.SYS or HIDOS.SYS access to
the upper memory address range that is causing the conflict. The following
recommendations apply to the EMM386.SYS driver for 386 and 486 computers,
or the HIDOS.SYS driver on 286 computers with shadow RAM.

Some typical symptoms of upper memory conflict include:

* inability to log onto networks

*inability to access hard or floppy disk drives

*inability to format low-density floppy disks in high density
drives

*error messages such as "card not found."

A good starting place to check for upper memory usage is the documentation
for any accessory boards or drivers you have installed; if they require
upper memory, it will usually be indicated in the documentation.

If you encounter such problems and suspect that upper memory
conflicts can be the cause, first REM out the memory manager line
of the config.sys file completely. If the problem disappears, you
know that the memory driver is part of the conflict and you can begin
to look at changing switches to correct the problem.  Use the DR DOS
EDITOR and change the following settings in your config.sys file:

1.If the EMM386.SYS /BDOS option is set to /BDOS=AUTO,
switch it to /BDOS=FFFF,

2.Save config.sys.

3.Reboot.

4.Retest.

*If the problem recurs, change the /R=AUTO setting to /R=NONE,
and then save the config.sys file, and reboot the computer to retest.

*You can also use the /EXCLUDE switch to exclude an area
of upper memory that the /AUTOSCAN feature detects as being available
but, in fact, might be used by another device, such as a network card.

The /EXCLUDE Option

If the hardware documentation does not specify a memory range to be
excluded, you can use the /EXCLUDE option to discover if there is
an upper memory conflict. This option is used to systematically exclude
sections of upper memory from being used by EMM386.SYS by excluding
upper memory "half-at-a-time." For example, use this "halving"
method to exclude the top half of the upper memory range first, reboot
the computer and test the problem. Then, if the problem recurs, change
the /EXCLUDE setting to exclude the lower half of upper memory, reboot,
and retest.

After discovering in which half of upper memory the conflict resides,
repeat the process by dividing that memory range in half.  You
can use this technique to break down the entire upper memory range,
half-by-half, until you pinpoint the area of conflict.

You must use the hexadecimal notation of the memory address with the
/EXCLUDE switch. The following brief explanation is provided for those
unfamiliar with using the hexadecimal system.

Hexadecimal Addresses

The 384 Kbyte range of upper memory resides between the hexadecimal
memory addresses of A000 and FFFF. The upper half of this range lies
between the addresses D000 and FFFF; the lower half lies between A000
and CFFF.  Because A000 to BFFF is typically reserved for video display,
you will normally work only with addresses C000 to FFFF.

To exclude the lower half of the C000 to FFFF range, enter the following
/EXCLUDE command in your EMM386.SYS or HIDOS.SYS line in the config.sys
file:

/E=C000-DFFF

Then, reboot your computer to test the exclusion. If the problem persists,
edit the /EXCLUDE statement to exclude the other half of the C000
to FFFF range by entering the following in the config.sys file:

/E=E000-FFFF

Continue excluding a smaller and smaller range of memory until you
have found the smallest possible exclusion, which still permits proper
functioning.

Note:
The first address in each range of memory (EXCLUDE, INCLUDE,
etc.) must end in "00" and the second must end in "FF."

Note that you can also exclude multiple memory ranges with the /EXCLUDE
statement by separating the ranges with a comma, e.g., /E=D000-D7FF,DA00-DBFF.

The chart below shows how this process works, and shows the memory
address for the 64 Kbyte range in the "D" segment of upper
memory.

D000-DFFF = 64K = D000-D7FF = 32K + D800-DFFF = 32K = 64K TOTAL
DOOO-D7FF = 32K = D000-D3FF = 16K + D400-D7FF = 16K = 32K TOTAL
D800-DFFF = 32K = D800-DBFF = 16K + DC00-DFFF = 16K = 32K TOTAL
D000-D1FF = 8K + D200-D3FF = 8K = 16K TOTAL
D400-D5FF = 8K + D600-D7FF = 8K = 16K TOTAL
D800-D9FF = 8K + DA00-DBFF = 8K = 16K TOTAL
DC00-DDFF = 8K + DE00-DFFF = 8K = 16K TOTAL

(The first "D" in each hex address above can be replaced with
C, E, or F when working with those segments.)

Once you find the conflicting range of upper memory, permanently exclude
it from being used by EMM386.SYS or HIDOS.SYS by using the /EXCLUDE
statement.

Video Problems

If you experience problems with your video display after installing
MemoryMAX drivers, a possible cause is that your video adapter is
attempting to use some of the same upper memory addresses being allocated
by EMM386.SYS or HIDOS.SYS.

A quick way to determine if your current memory setup is causing a
conflict with a video (or other device) board is to "turn off
the entire memory driver line in your config.sys file by using the
REM command or the "?" technique discussed previously in "Isolating
the Problem."  If the problem does not recur with the memory driver
"turned off," the cause of the problem is probably an upper
memory conflict.

See "The DR DOS MemoryMAX System" on page 2 for information about
how to determine if upper memory is being used by drivers and hardware
boards.

Use the EMM386.SYS or HIDOS.SYS /VIDEO option to reserve graphics
memory addresses normally occupied by video display adapters (see
Chapter 11 of the DR DOS 6.0 User Guide).

If the /VIDEO option is set, and the video corruption is occurring
with a graphics program, be sure that the MEMMAX -V switch is operative.
When only text displays are required, the MEMMAX +V switch can borrow
some of the graphics memory areas and add it to conventional memory,
providing more space for text applications. However, if an application
requires graphical displays, you must be sure this memory area is
available to video by issuing the MEMMAX -V command.

If the video display is corrupted only during use with the DR DOS
TaskMAX task switcher, refer to the readme file (in
the DR DOS directory) or the Release Note for instructions on how
to use the TaskMAX /F switch.

Network Hardware Interfacing

It is common for network hardware to utilize areas of upper memory
and thus conflict with MemoryMAX allocations of that memory.  If this
occurs, you might be unable to log onto the network or random lockups
might occur. See "Upper Memory Conflicts" on page 17, and "Using Network
Software" on page 30, for a full discussion of how to deal with upper memory
conflicts such as these and how to use the EMM386.SYS /EXCLUDE switch
to exclude the conflicting areas of upper memory.

Another possible cause of network problems is that your network driver
is designed for use with MS-DOS versions other than versions
3.3+. Network drivers designed for use with MS-DOS versions 4.0+ and
5.0 would not be appropriate for the DR DOS 6.0 operating system.
(See "Using Network Software" on page 30)

Floppy Drive Does Not Work

If you have installed Super PC-Kwik and have enabled the /D+
switch, your disk controller must be 100% IBM compatible. Reset
the /D+ switch to /D- (the /D# switch works on some controllers) to
turn off PC-Kwik's advanced caching for the floppy drives (advanced
caching for your hard drive remains in effect).

SCSI Disk Drive Problems

The DR DOS 6.0 operating system supports virtual DMA and bus master
controllers. Any problem with SCSI drives is probably due to a memory
conflict (see "Upper Memory Conflicts" on page 17).

Expanded (EMS) Memory Problems

If a program that requires EMS memory reports that no EMS is available
or locks up when executed, the problem might be that the application
assumes that the LIM page frame starts at a specified address.

Remedy this problem by ensuring that the LIM page frame defined in
the application's SETUP program or documentation matches the settings
in EMM386.SYS or EMMXMA.SYS. The /F= switch defines the start
of the LIM page frame.

Another cause of insufficient LIM memory occurs if you are using TaskMAX
in expanded memory and too many tasks have been loaded. Unload a few
of the tasks and restart the program.

Error message: "Packed file is corrupt."

This error might occur when the first 64 Kbytes of conventional memory
(called low memory) have been made available through the use of MemoryMAX.
Normally, the operating system occupies this entire area.  Some applications
were written using packing utilities that become confused when run
in this low memory.  If this happens, the following message appears:

Packed file is corrupt.

For an easy workaround, use the MEMMAX -L command to disable low memory
before running the application.  Then load and run your application.  After
exiting the application, use MEMMAX +L to enable the low memory area
once again.

Because this problem can occur with other memory managers, including
QEMM.386, your application vendor might be able to supply you with
an updated application that does not exhibit this problem.