NOVELL TECHNICAL INFORMATION DOCUMENT DOCUMENT PROCESSING INFO: Replaces Document FYI-M-1302 TITLE: Troubleshooting Memory Conflicts DOCUMENT ID: TID800077 DOCUMENT REVISION: A DATE: 22AUG94 AUTHOR: KBANTA;DPARTRID ALERT STATUS: Yellow DISTRIBUTION: Public INFORMATION TYPE: Symptom Solution README FOR: NA NOVELL PRODUCT CLASS: Desktop Products NOVELL PRODUCT and VERSION: DR DOS 6.0 CATEGORY: Memory ABSTRACT: NA ----------------------------------------------------------------- DISCLAIMER THE ORIGIN OF THIS INFORMATION MAY BE INTERNAL OR EXTERNAL TO NOVELL. NOVELL MAKES EVERY EFFORT WITHIN ITS MEANS TO VERIFY THIS INFORMATION. HOWEVER, THE INFORMATION PROVIDED IN THIS DOCUMENT IS FOR YOUR INFORMATION ONLY. NOVELL MAKES NO EXPLICIT OR IMPLIED CLAIMS TO THE VALIDITY OF THIS INFORMATION. ----------------------------------------------------------------- SYMPTOM Insufficient conventional memory. SOLUTION SOLUTION 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 may still occur. 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 the application. SYMPTOM HILOAD, HIINSTALL, and HIDEVICE do not appear to work. SOLUTION Each of these commands requires the availability of UMBs (Upper Memory Blocks. Verify that the UMBs are available by using the DR DOS MEM /B or /U command to see a report of the memory usage. Available UMBs 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 used, check the 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 addresses specified by these switches have been correctly set (a common error is using an "oh" instead of a zero). 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 (which disables 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, it may be because some device drivers and TSR programs expand when they initialize and take up considerably more RAM than they will ultimately need. SYMPTOM Computer will not boot, or locks up. SOLUTION Reboot the computer with a bootable floppy disk in drive A:. Edit the CONFIG.SYS and/or AUTOEXEC.BAT files to turn off and isolate those lines in the files that could 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 switches to remedy the problem. If a hardware device is not causing the conflict, and the lockup occurs with a particular program, this program may become confused about when upper or low memory is available. Try using the command MEMMAX -U and/or MEMMAX -L before loading the program. SYMPTOM Inability to log onto networks; inability to access hard or floppy disk drives; error messages such as "card not found". SOLUTION The computer or its accessories may 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. A good starting place to check for upper memory usage is the documentation for any accessory boards or drivers you have installed. If upper memory is required it is usually indicated in the ocumentation. If you encounter such problems and suspect that upper memory conflicts are the cause, first REM out the memory manager line in the CONFIG.SYS file. 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. If the EMM386.SYS /BDOS option is set to /BDOS=AUTO, switch it to /BDOS=FFFF. Save CONFIG.SYS and reboot the computer to 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. 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 may be unable to log onto the network or random lockups could occur. Another possible cause of network problems is that the 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. INABILITY TO ACCESS HARD OR FLOPPY DISK DRIVES. If you have installed Super PC-Kwik and have enabled the /D+ switch, the 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 the hard drive remains in effect). The DR DOS 6.0 operating system supports virtual DMA and bus master controllers. Any problem with SCSI drives is probably due to an memory conflict. SYMPTOM Not enough (or no) EMS memory available; or lockup when executing a program. SOLUTION If a program that requires EMS memory reports that no EMS is available or locks up when executed, the problem could 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. SYMPTOM Video problems SOLUTION If you experience problems with the video display after installing MemoryMAX drivers, a possible cause is that the 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 the current memory setup is causing a conflict with a video (or other device) board is to turn off the entire memory driver line in the CONFIG.SYS file by using the REM command or the "?" technique. If the problem does not recur with the memory driver "turned off," the cause of the problem is probably an upper memory conflict. Use the EMM386.SYS or HIDOS.SYS /VIDEO option to reserve graphics memory addresses normally occupied by video display adapters. 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 DR DOS 6.0 Release Notes for instructions on how to use the TaskMAX /F switch. SYMPTOM Error message: "PACKED FILE IS CORRUPT." SOLUTION This error can 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 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 the application. After exiting the application, use MEMMAX +L to enable the low memory area once again. This problem can occur with other memory managers, including QEMM386. The application vendor may be able to supply you with an updated application that does not exhibit this problem. 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, is actually in use by another device, such as a network card. SYMPTOM General problematic behavior SOLUTION Isolate the problem with the following techniques: USING REM Before experimenting with the CONFIG.SYS and AUTOEXEC.BAT files, create a bootable floppy disk containing the unedited, original versions of the CONFIG.SYS and AUTOEXEC.BAT. This way if there is the need to reboot the computer from the A: drive. The most recent configuration is available. The original CONFIG.SYS and AUTOEXEC.BAT files could then be copied back to the boot disk. After turning off the suspect lines with a REM statement, reboot the computer to retest the driver/application with which you first encountered the memory problem. If the system runs correctly, reenter the 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. 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 a particular line is not causing a problem it can be reactivated by removing the REM statement. USING ? You can also use the DR DOS conditional "?" statement to activate/deactivate CONFIG.SYS line commands. If you use this option, make careful note of whether you answered "yes" or "no" to loading each line. USING 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. For example, use this 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 and reboot to 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. Note that sometimes, you will not be able to determine which "half" the problem exists in, because the problem area may be right around the half-way point. In this case, you may need to exclude the entire upper memory range. 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 the EMM386.SYS or HIDOS.SYS line in the CONFIG.SYS file: /E=C000-DFFF Then, reboot the computer to test the exclusion. If the problem persists, edit the /EXCLUDE switch 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." You can also exclude multiple memory ranges with the /EXCLUDE switch 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 D000-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 switch. ADDITIONAL REFERENCES: DR DOS 6.0 USER GUIDE - Chapters 7, 10, 11; TIDs- 800021, 800072, 800073, 800074, 800058; DR DOS 6.0 OPTIMIZATION AND CONFIGURATION TIPS; README FILE IN THE DRDOS DIRECTORY; RELEASE NOTES ----------------------------------------------------------------- Any trademarks referenced in this document are the property of their respective owners. Consult your product manuals for complete trademark information. -----------------------------------------------------------------