TITLE: Basic Memory Optimization and Troubleshooting DOCUMENT ID: TID14912 DOCUMENT REVISION: 2 DATE: 27FEB94 ALERT STATUS: Yellow README FOR: NA NOVELL PRODUCT and VERSION: Novell DOS 7 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. --------------------------------------------------------------------- ISSUE: Because the Novell DOS 7 operating system has been designed to work with all IBM-compatible personal computers and software applications there is no single, perfect, memory setup that will optimize memory use for all situations. Memory optimization will depend on both your particular hardware setup and the software applications you will be using. With some trial-and-error system fine tuning, you can optimize Novell DOS 7 memory management to meet your particular needs. Following are techniques and suggestions that will help optimize your computer's software setup. CHANGING THE ORDER OF MEMORY ALLOCATION The first step in optimizing the system memory can be as simple as rearranging the order in which memory blocks are assigned by the CONFIG.SYS and AUTOEXEC.BAT files. The general rule is to use upper memory and high memory as much as possible to free conventional memory for applications. If there are any add-on boards that use RAM, make sure that they are configured so that their RAM is allocated from the beginning or the end of upper memory. For example, place a network board immediately above the video RAM area instead of in the middle of upper memory. Device drivers and TSRs can then be loaded into upper memory. For best memory allocation, those drivers and TSRs that occupy the largest blocks of memory should be loaded first and contiguously. For example, if there are three device drivers and two TSR programs that need to be loaded, they should be loaded in descending order in your CONFIG.SYS file, largest to smallest. The documentation for the drivers and TSRs should indicate the amount of RAM they require. If the documentation does not indicate their size, this can be determined by loading the driver or TSR and then using the MEM /U or /B command to see a report of memory use. DOSBOOK MEM provides a full description of the MEM command. EXPANDING FILES If, after determining the size of the drivers and TSRs and loading them into high memory, a driver or program fails to run properly or produces an out of memory error message, the problem may be that the driver or TSR is expanding itself in RAM. Some device drivers and TSRs occupy a minimal amount of RAM after they are loaded into memory; however, while initializing, they might expand and take up considerably more RAM than they will ultimately need. Another method of verifying a program's true RAM size is to load it into conventional memory, activate the program, then run the MEM /AP or MEM /U command to see the actual amount of RAM the program occupies. If the program or driver expands itself in RAM and you want to load it into upper memory, you will have to allow sufficient upper RAM to accommodate the initialization size of the program. Using some trial-and-error methods to determine this size might be necessary. EXAMPLE: Assume the following Device Drivers and TSRs are to be loaded: Driver #1 = 13 KB of RAM Driver #2 = 10 KB of RAM Driver #3 = 16 KB of RAM TSR #1 = 4 KB of RAM TSR #2 = 6 KB of RAM Using the HIDEVICE, DEVICEHIGH or HIINSTALL commands, enter these lines in the CONFIG.SYS file: HIDEVICE = C:\DRIVER#3.SYS ; which uses 16 KB RAM HIDEVICE = C:\DRIVER#1.SYS ; which uses 13 KB RAM HIDEVICE = C:\DRIVER#2.SYS ; which uses 10 KB RAM HIINSTALL = TSR#2 ; which uses 6 KB RAM HIINSTALL = TSR#1 ; which uses 4 KB RAM NOTE: Exceptions to loading TSRs and drivers in the largest-first order described in this example may exist. Some device drivers must be loaded in a specific order. Read the manufacturer's documentation carefully before installing any driver. In this example, the two TSRs can be loaded with LOADHIGH or LH command in the AUTOEXEC.BAT file. For a discussion of the HIINSTALL, DEVICEHIGH, and LOADHIGH commands, refer to DOSBOOK. LIM PAGE FRAME Some applications run better with the availability of LIM memory (sometimes called EMS or expanded memory). The documentation for each of your applications will indicate if LIM memory is required. If the application does not require LIM memory, make sure that no LIM page frame is defined. This will save 64 KB of upper memory. In the EMM386.EXE line of your CONFIG.SYS file, disable the page frame with the switch /FRAME=NONE. If you are using HIMEM.SYS on a machine with a LIM 4.0 memory card, specify /CHIPSET=AUTO. AFTER INSTALLING NOVELL DOS 7 Some problems that may you may run across after installing the Novell DOS 7 memory drivers include the following: 1. Insufficient conventional memory to load a particular driver or program. 2. LOADHIGH, HIINSTALL, or DEVICEHIGH features do not seem to operate correctly. 3. Computer lock-ups. 4. Upper memory conflicts. 5. Expanded memory problems. 6. Video problems. 7. Error message: "Packed file is corrupt." Each of these problems and the techniques to correct them are described in the following list. Specific information on how to test and eliminate the problems are found in DOSBOOK under the TROUBLESHOOTING subject. 1. Insufficient Conventional Memory After using the Novell DOS 7 memory management system to increase conventional memory, a problem due to insufficient memory should not exist. However, if a large number of device drivers or TSRs are in use, this problem may still occur. In case an earlier command or batch file executed earlier disabled low memory, try using the MEMMAX +L command. Finally, if the application does not use the graphics display area, try the /V switch of the Novell DOS 7 memory manager followed by MEMMAX +V before loading the application. 2. LOADHIGH, HIINSTALL, or DEVICEHIGH Considerations Each of these commands requires the availability of UMBs (Upper Memory Blocks). Verify that the UMBs are available by using the Novell DOS 7 MEM /B or MEM /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 EMM386.EXE or HIMEM.SYS memory manager is required before a LOADHIGH, HIINSTALL, or DEVICEHIGH command will take effect. 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, and /EXCLUDE switches to ensure that any upper memory addresses specified by these switches have been correctly set (a common error is using the letter "O" instead of the number zero). If you do not require the use of expanded memory, set the /FRAME switch to /FRAME=NONE. The LOADHIGH command must be invoked before using the MEMMAX -U command (which disables upper memory). Use the MEMMAX +U command to reenable upper memory, if necessary. If sufficient upper memory appears to be available but LOADHIGH, HIINSTALL, or DEVICEHIGH fails to put a particular TSR or driver into upper memory, the device driver or TSR program may have expanded when it initialized, and it took up considerably more RAM than it ultimately needs. 3. Computer Will Not Boot or It Locks Reboot the computer with a bootable floppy disk in the A: drive. Edit the CONFIG.SYS and 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 Novell DOS 7 memory manager has moved something into a region of upper memory required by a hardware device driver. Use the /EXCLUDE switch to remedy the problem. If a hardware device is not causing the conflict and the lockup occurs with a particular program, this program may not be able to distinguish when upper or low memory is available. Try using the command MEMMAX -U or MEMMAX -L before loading the program. 4. Upper Memory Conflicts Some typical symptoms of upper memory conflict include the following: A. Inability to log onto networks B. Inability to access hard or floppy disk drives C. Error message, such as "card not found" The computer or its accessories may be using upper memory addresses that are also being accessed by the Novell DOS 7 memory manager. To prevent this, exclude EMM386.EXE or HIMEM.SYS access to the upper memory address range that is causing the conflict. The following recommendations apply to the EMM386.EXE driver for 386, 486 and Pentium computers, or the HIMEM.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 that you have installed. If upper memory is required, it is usually indicated in the documentation. If you encounter such problems and suspect that upper memory conflicts are the cause, first insert REM at the beginning of 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 problem recurs, change the /R=AUTO setting to /R=NONE, save the CONFIG.SYS file, and reboot the computer to retest. A. Network Hardware Interfacing It is common for network hardware to use areas of upper memory and thus conflict with Novell DOS 7 allocations of that memory. If this occurs, you may be unable to log on to 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 version 6.0. Network drivers designed for use with MS-DOS versions 3.0 and 4.0+ may not be appropriate because Novell DOS 7 operating system reports version 6.0. B. Inability To Access Hard or Floppy Disk Drives If you have installed NWCACHE and have enabled the /D+ switch, the disk controller must be 100 percent IBM compatible. Reset the /D+ switch to /D- (the /D# switch works on some controllers) to turn off NWCACHE advanced caching for the floppy diskette drives (advanced caching for the hard disk remains in effect). The Novell DOS 7 operating system supports virtual DMA and bus master controllers. Any problem with SCSI drives is probably caused by a memory conflict. 5. Expanded (EMS) Memory Problems If a program that requires EMS memory reports that no EMS is available or locks up when executed, the problem could be caused from an application that assumes that the LIM page frame starts at a specific 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.EXE or EMMXMA.SYS file. The /FRAME= switch defines the start of the LIM page frame. Another cause of insufficient LIM memory occurs if you are using the Novell DOS 7 Task Manager in expanded memory and too many tasks have been loaded. Unload a few of the tasks and restart the program. 6. Viedo Problems If you experience problems with the video display after installing Novell DOS 7 drivers, a possible cause is that the video adapter is trying to use some of the upper memory addresses being allocated by EMM386.EXE or HIMEM.SYS. A quick way to determine if the current memory setup is causing a conflict with a video (or other) board is to disable the entire memory driver line in the CONFIG.SYS file by using the REM command or booting with the F8 function key. If the problem does not recur with the memory driver disabled, the cause of the problem is probably an upper memory conflict. Use the EMM386.EXE or HIMEM.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 Novell DOS 7 Task Manager, refer to DOSBOOK. 7. Error Message: "PACKED FILE IS CORRUPT." This error can occur when the first 64 KB of conventional memory (called low memory) have been made available by the Novell DOS 7 memory manager. Normally, the operating system occupies this entire area. Some applications use packing utilities that become unable to process commands 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. After exiting the application, use MEMMAX +L to enable the low memory area 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 is in use by another device, such as a network board. ISOLATING THE PROBLEM USING "REM" Before experimenting with the CONFIG.SYS and AUTOEXEC.BAT files, create a bootable floppy disk containing the unedited, original versions of CONFIG.SYS and AUTOEXEC.BAT files. With this setup 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 and application with which you first encountered the memory problem. If the system runs correctly, reedit the CONFIG.SYS or AUTOEXEC.BAT file and remove the REM command from one line, then reboot, and reload the application. Continue this process until you again come across 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. EXAMPLE: To disable the line DEVICE = C:\NWDOS\EMM386.EXE /FRAME=AUTO add the REM comment to the beginning of the line: REM DEVICE = C:\NWDOS\EMM386.EXE /FRAME=AUTO If a line is not causing the problem, it can be reactivated by removing the REM statement. USING ? You can also use the Novell DOS 7 conditional "?" statement or F8 function key to activate or deactivate CONFIG.SYS and AUTOEXEC.BAT commands. If you use this option, make 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 determine whether an upper memory conflict exists. This option is used to systematically exclude sections of upper memory from being used by EMM386.EXE. 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 the half of upper memory in which 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 KB 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 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 smaller and smaller range of memory until you have found the smallest possible exclusion that still permits proper functioning. NOTE: The first address in each range of memory (EXCLUDE, INCLUDE, and so forth) 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 as shown in the following example: Example: /E=D000-D7FF,DA00-DBFF The following chart shows how this process works and shows the memory address for the 64 KB 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.) After you find the conflicting range of upper memory, permanently exclude it from being used by EMM386.EXE or HIMEM.SYS by using the /EXCLUDE switch. ADDITIONAL REFERENCES: DOSBOOK COMMANDS, CONTENTS, CONFIGURING, or INDEX --------------------------------------------------------------------- Any trademarks referenced in this document are the property of their respective owners. Consult your product manuals for complete trademark information. ---------------------------------------------------------------------