EMM386 and EXCEPTION ERRORS
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EMM386 provides access to the upper memory area to load programs and device drivers into upper memory blocks (UMBs) and can use extended memory to simulate expanded memory. This device driver must be loaded by a <DEVICE> command in your CONFIG.SYS file and can be used only on computers with an 80386 or higher processor. No version of DOS dBASE needs EMM386, on the other hand the inclusion of EMM386 in the environment should not be a problem. Most EMM386 problems can be corrected with proper configuration. Errors with dBASE and EMM386 are usually because dBASE's memory manager is in conflict with other devices, or cannot access needed memory used by another device. The most common error is an Exception error. Exception errors are unusual or invalid conditions associated with the execution of a particular instruction by the processor. The processor signals the memory manager that an error has occurred and the memory manager then reports this error to the user. For example the 80386 recognizes 16 different exceptions:
To trouble shoot test with a clean boot:
*** and only other _essential_ files such as disk drivers and compression utilities. Remove all other drivers to eliminate other possible conflicts. NOTE: Sometimes the order in which you load device drivers makes the difference. Test. Now add just EMM386, test again. If the problem disappears when EMM386 or any other memory manager is not loaded; you can isolate the problems by removing each switch for EMM386.EXE one by one and rebooting to isolate the problem further. Another method is to edit the CONFIG.SYS file as follows: device=c:\dos\emm386.exe x=a000-f7ff nohi noems novcpi nomovexbda notr If the problem disappears after loading EMM386.EXE as specified above, EMM386.EXE itself is not the source of the problem and proper configuration should get you around the problem. See the following Microsoft document for further details, Title: Troubleshooting MS-DOS 6.x and EMM386.EXE Title: Exception Errors with EMM386.SYS / EMM386.EXE Available on Compuserve, GO MSKB (Microsoft Knowledgebase). If you continue to receive EXCEPTION errors with EMM386 configure as above, verify if the error occurs on other machines. If it doesn't, note the differences between the machines.
Other factors: *1 Lib 10: QTEMP.FAQ Configuring dBASE temporary files Correct any disk errors. Disk diagnostic tools such as Norton Disk Doctor or PC TOOLS should be considered before CHKDSK /F, since their error checking and recovery routines are more comprehensive. *2 *3 The Compiler is a 32 bit program and the linker is a 16 bit program. At a DOS level you can run both a 16 and 32 bit program back to back without a problem. But if you are within Windows and start a DOS session you can only run one type of session a 16 or 32 bit. Windows will not allow memory mode switching. So the way to Compile within Windows is to open two DOS sessions and Link in one and Compile in the other. *4 Yes but the problem more precisely is that some other device is also using it. By excluding it, you are mapping memory, and dBASE's virtual memory manager reads this map at start up and knows not to use it. Many network cards make use of the CC00-CFFF range so this may be a range to exclude. For other ranges the documentation for the add-on cards used in the system should indicate the range of memory that is being used. If the hardware documentation is not available or does not give the required information, you can use the Microsoft Diagnostic Utility (MSD) to identify the memory regions. *5
*6 WORKAROUND: SET DOS16M environmental variable in the AUTOEXEC.BAT file or before starting dBASE to a value greater than the size of the EMS pool.
For example if you have the following line: DEVICE=EMM386.EXE 2048 [ DEVICE=EMM386.EXE <memory> <memory> - Specifies the maximum amount of extended memory that you want EMM386 to provide as EMS/VCPI memory. ] SET DOS16M=:3072 Or, the memory parameter on the DEVICE=EMM386.EXE may be removed. For example, there is a line similar to the following in config.sys DEVICE=EMM386.EXE 2048 remove the number '2048'. Now run the PMINFO.EXE stats utility and look at the 3rd line of stats under the extended memory column. This value is the amount of extended memory v2.0 is able to use. Once the 3rd line of stats indicates that at least 1024K of extended memory is available to DOS/16M program, v2.0 should then begin to run. For more information on SET DOS16M see *7
In most cases this information is of limited help to the average user. If you wish/need to pursue the above information further see the following Quarterdeck help file ( GO QUARTERDECK ). ID:13 QEMM-386: Exception #13 Explained Subject: Detailed explanation of QEMM-386's Exception #12 and Exception #13 messages, why they are reported, and steps to identify their causes. Whether or not you have QEMM, this is an EXCELLENT discussion on the information returned from exception errors! *8 GO MSKB ( Microsoft Knowledge Base ) Title: Exception Errors with EMM386.SYS / EMM386.EXE If you are using QEMM see above mentioned Quarterdeck file in number 7 and, GO QUARTERDECK ID:X3 Troubleshooting Exception #6, #12, and #13 Errors Subject: Detailed explanation and troubleshooting procedures for Exception #6, #12, and #13 error messages and system lockups. |