NOVELL TECHNICAL INFORMATION DOCUMENT DOCUMENT PROCESSING INFO: Replaces Document FYI-M-1301 TITLE: BASIC MEMORY OPTIMIZATION DOCUMENT ID: TID800073 DOCUMENT REVISION: A DATE: 18AUG94 AUTHOR: KBANTA;DPARTRID ALERT STATUS: Yellow DISTRIBUTION: Public INFORMATION TYPE: Issue README FOR: NA NOVELL PRODUCT CLASS: Desktop Products NOVELL PRODUCT and VERSION: DR DOS 6.0 CATEGORY: Memory ABSTRACT: This document discusses general methods of obtaining the best memory management possible on a system with DR DOS 6.0 installed. ----------------------------------------------------------------- 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 DR DOS 6.0 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 both on your particular hardware setup and the software applications you will be using. However, with some trial-and-error system fine tuning, you can optimize DR DOS memory management to meet your particular needs. What follows 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. With this in mind, you should typically use HIBUFFERS and relocate the DR DOS kernel code to high memory. This is done by using the /BDOS=FFFF option of the DR DOS memory management drivers (HIDOS.SYS and EMM386.SYS). If there are any add-on cards 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 card 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 ordered 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. Chapter 10 of the DR DOS 6.0 User Guide provides a full description of the MEM command. Chapter 12 discusses loading device drivers and TSRs. 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 TSR's occupy a minimal amount of RAM after they are loaded into memory, but, while initializing, might actually expand and take up considerably more RAM than they will ultimately need. Another method of verifying the program's true RAM size is to load it into conventional memory, activate the program, and then run the MEM /B 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 memory RAM to accommodate the initialization size of the program. It might be necessary to use trial-and-error to determine this size. EXAMPLE Assume the following Device Drivers and TSR's are to be loaded: Driver #1 = 13Kbyte of RAM Driver #2 = 10Kbyte of RAM Driver #3 = 16Kbyte of RAM TSR #1 = 4Kbyte of RAM TSR #2 = 6Kbyte of RAM Using the MemoryMAX HIDEVICE and/or HIINSTALL commands, enter these lines in the CONFIG.SYS file: HIDEVICE = C:\DRIVER#3.SYS ; which uses 16kb RAM HIDEVICE = C:\DRIVER#1.SYS ; which uses 13kb RAM HIDEVICE = C:\DRIVER#2.SYS ; which uses 10kb RAM HIINSTALL = TSR#2 ; which uses 6kb RAM HIINSTALL = TSR#1 ; which uses 4kb RAM NOTE: There can be exceptions to loading TSRs and drivers in the largest first system described above. Some device drivers must be loaded in a specific order. Read the manufacturer's documentation carefully before installing any driver. Note that in the above example, the two TSRs can be loaded with the HILOAD command in the AUTOEXEC.BAT file. For a discussion of the MemoryMAX HIINSTALL, HIDEVICE, and HILOAD commands, see "MemoryMAX System Commands and Drivers" on page 4 in the DR DOS 6.0 User Guide. 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, be sure that no LIM page frame is defined. This will save 64 Kbytes of upper memory. In the EMM386.SYS line of your CONFIG.SYS file, disable the page frame with the switch /F=NONE. If using HIDOS.SYS on a machine with a LIM 4.0 memory card, the page frame can be disabled by specifying /CHIPSET=EMSALL. ----------------------------------------------------------------- Any trademarks referenced in this document are the property of their respective owners. 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