MS-DOS 8.0/MS-DOS8.iso/SOFTWARE/QEMM/TECHNOTE/MAXMEM.TEC

Text File | 1997-05-15 | 16KB | 333 lines

                 Maximizing Conventional Memory

 Quarterdeck Technical Note #296              Filename: MAXMEM.TEC
 by Michael Bolton                          CompuServe: MAXMEM.TEC
 Last revised:  4/02/95                       Category: QEMM

 Subject: Providing the maximum possible amount of conventional
          memory in DOS, DESQview, DESQview/X, and Microsoft
          Windows.

 DOS and the programs that run under it are limited, except in
 special circumstances, to the first megabyte of the processor's
 address space. This has consequences for DOS programs, and for
 operating environments such as Quarterdeck's DESQview and
 DESQview/X, and Microsoft Windows.

 Documentation for Quarterdeck products contains extensive
 information on memory management, and should be consulted for more
 detailed study. This technical note provides a list of the most
 important quick tips for assuring that you have the maximum amount
 of conventional memory available, whether you are working from
 DOS, DESQview, DESQview/X, or Microsoft Windows.  Note that many
 of the QEMM features suggested below will be enabled for you
 automatically at the time you install QEMM.

 1. Use QSETUP

 The QSETUP program that comes with QEMM runs under DOS and
 Windows.  Its job is to provide you with an easy-to-use way of
 configuring QEMM's features, which are described below.  QSETUP
 will allow you to configure QEMM, to active the DOS-Up feature
 (including DOS=HIGH), and to enable Stealth D*Space.  At the end
 of the QSETUP process, you will be given an opportunity to run
 OPTIMIZE.

 2. Use OPTIMIZE

 The OPTIMIZE process uses QEMM's RAM parameter and the LOADHI
 utilities to move as many programs as possible out of the
 conventional memory area and above 640K.  If necessary, OPTIMIZE
 will offer the option to activate QEMM's Stealth parameter
 (detailed below).  You should run OPTIMIZE

 - after running QSETUP
 - after changing CONFIG.SYS or AUTOEXEC.BAT
 - after adding or removing hardware from your system

 Regardless of the change that you have made, running OPTIMIZE will
 ensure that you get the maximum conventional memory.

 2. Use Manifest.

 The Manifest program that comes with QEMM provides you with a
 detailed view of the configuration of your PC.  When run under
 DESQview, DESQview/X, or Microsoft Windows, Manifest can tell you
 about the state of the current window.  Manifest also includes
 detailed hints on how to get more conventional memory on your PC;
 check the Hints Overview AND the Hints Detail screen.

 3. Use Stealth

 Go into Manifest, and inspect the QEMM Overview screen.  If the
 screen does not display "Stealth Type" and "Stealth ROMs" and if
 you have less conventional memory than you would like, run the
 QSETUP.  OPTIMIZE program again. When OPTIMIZE offers to test for
 Stealth compatibility, answer Yes, and if OPTIMIZE finds that
 Stealth is compatible with your system, OPTIMIZE will activate
 StealthROM.  StealthROM is quite robust and compatbile, and
 typically results in 83K of extra High RAM into which DOS programs
 can be loaded. If you are having compatibility problems with
 Stealth, consult your QEMM manual or "QEMM GENERAL
 TROUBLESHOOTING" (STEALTH.TEC).  The time you take in
 troubleshooting a Stealth conflict is well worth the memory gain.

 4. Use DOS-Up

 QEMM's DOS-Up feature moves parts of DOS, including FILES,
 BUFFERS, LASTDRIVE, the DOS Data Segment (which is a block of
 memory that DOS uses to keep track of its own operation), and the
 command processor (typically COMMAND.COM) high.  The DOS kernel
 itself may also be loaded high (see the next section).  Using
 DOS-Up can result in a saving of 7K-70K of conventional memory. To
 activate DOS-Up, go into QSETUP, choose DOS-Up Options, and enable
 Partial (if you are you a DESQviewor DESQview/X user) or All (if
 you do not use DESQview or DESQview/X). Save your configuration,
 and run OPTIMIZE.

 5. Use DOS=HIGH

 One of the features that you may activate from QSETUP is the
 DOS=HIGH feature.  This loads the DOS kernel -- about 43K of code
 -- into the first 64K above the 1024K line, thanks to technology
 originally discovered by Quarterdeck in 1986.  If you are a
 DESQview or DESQview/X user, it is typically worthwhile NOT to use
 this feature.  DESQview and DESQview/X use this memory (called the
 High Memory Area, or HMA) more effectively than DOS does.
 Generally, you will receive maximum memory gains if you use
 DOS=HIGH, unless you are using DESQview or DESQview/X. To activate
 DOS=HIGH, go into QSETUP, choose DOS-Up Options, and enable All
 (or choose Partial and ensure that DOS=HIGH is activated.  Save
 your configuration, and run OPTIMIZE.

 6. Use ST-DSPC

 QEMM 7.0 and later come with a feature for DOS's disk compression
 software (DoubleSpace, and in DOS 6.22, DriveSpace) for which
 Quarterdeck has special support.  The code for the disk
 compression software can be placed into expanded memory, replacing
 a driver tht is typically over 40K with one that is typically
 under 4K.  This generally represent substantial memory savings;
 although DoubleSpace can be loaded high, it still takes memory in
 the first megabyte of adddress space. Stealth D*Space removes most
 of this overhead. If you are using DOS's disk compression,
 activate QEMM's Stealth D*Space feature. To do this, go into
 QSETUP, choose ST*DPACE Options, and choose L for Enable or
 disable Stealth D*Space.  On the next screen, choose Y to enable
 Stealth D*Space.  Save your configuration, and run OPTIMIZE.

 7. Use QEMM's Stacker Feature

 QEMM comes with a feature that can allow Stacker 4 to put most
 of its code outside of conventional memory.  Stacker's overhead in
 conventional memory or in High RAM to as little as 10K on MS-DOS 6
 systems.  This can save a great deal of memory indeed on Stac'd
 systems whose hard drives have large cluster sizes.

 A program is available to enable users of Stacker 4 to enable this
 feature is available to all registered users of Stacker 4, either
 from Stac Electronics or from Quarterdeck, under the filename
 S4UP.EXE.

 To get your copy of this file, join the CompuServe forum for
 either Quarterdeck or Stac, by typing GO QUARTERDECK or GO STAC at
 any CompuServe main prompt. Alternatively, using your modem, call

 Stac Electronics BBS  [phone]
 Quarterdeck BBS       [phone]

 Oce you have acquired this file and run the update, you may
 activate the Stacker feature in this way:

 1. If you are currently inside Windows, exit it.
 2. At the DOS prompt, change to the Stacker directory.
 3. Type ED /I
 4. Press Enter to insert a new line.
 5. On this new line, type /QD
 6. Press Ctrl-Z to exit the editor, and save your changes.
 7. Restart your system to put the changes into effect.

 As usual, since this represents a change to your CONFIG.SYS, use
 the OPTIMIZE program again.

 8. Use EMS or XMS

 Many programs -- TSRs, device drivers, and applications -- are
 able to use expanded memory (EMS) or extended memory (XMS) reduce
 their DOS overhead.  These features are sometimes automatic, but
 are sometimes enabled via parameters (or command-line switches) or
 initialization files.  Additionally, parameters may exist that
 simply reduce the program's size -- sometimes by disabling
 unneeded features -- without using expanded or extended memory.
 This may require a little research on your part -- such parameters
 are found in the online help or in the documentation for the
 program.  However, this research can reap rich rewards in memory
 savings.  Some programs that run only in conventional memory do
 not have switches to activate EMS or XMS usage, but instead come
 with EMS-using equivalents.  Novell's NETX network shell is an
 example of this; while it uses 43K of conventional memory, and
 does not use EMS, it is typically accompanied by EMSNETX (which
 requires less than 10K of coventional memory) and XMSNETX (which
 takes similar overhead). These programs are functionally
 equivalent to NETX, but save considerable amounts of memory.

 Also consult the Quarterdeck Technical Note "Why the EMS Page
 Frame is Important" (FRAME.TEC)

 9. Use Vidram

 VIDRAM provides up to 96K of extra conventional memory if you are
 using text programs.  VIDRAM does this by borrowing address space
 from the VGA graphics buffer on your video card.  VIDRAM can be
 enabled or disabled on the fly, and can also run in text windows
 within Microsoft Windows.  DESQview/X users in particular can take
 advantage of VIDRAM (see the next section of this note.)  In order
 to activate VIDRAM, simply type

 VIDRAM ON

 On some video cards, it may be necessary to add the parameter
 VIDRAMEMS (VREMS) to the QEMM386.SYS line in CONFIG.SYS for VIDRAM
 to work properly from the DOS prompt.  This parameter is
 incompatible with Microsoft Windows.  However, even on such cards,
 VIDRAM will work in a Microsoft Windows window without the VREMS
 parameter.

 10. Streamline your CONFIG.SYS and AUTOEXEC.BAT

 If you are loading many device drivers or TSRs, they will have a
 direct impact on conventional memory.

 Programs such as disk caches, RAM drives, or video speedup
 utilities typically consume memory in the first megabyte.  If you
 do not need these drivers, or are unsure of their usefulness, you
 may consider removing them to see the impact on performance.  You
 may find that the benefit of additional memory outweighs the gains
 provided by such utilities.  Arriving at optimal performance will
 require you to decide which features are more important than
 others.

 If you are using DESQview, DESQview/X, or Microsoft Windows, TSRs
 or device drivers such as ANSI.SYS, DOSKEY or Sidekick should be
 removed from the AUTOEXEC.BAT and loaded in a window instead. Such
 programs only have a memory impact on the window in which they are
 loaded, but if loaded before your operating environment will
 reduce the size of all of the windows on your system.

 11. Consider removing QDPMI

 Many modern DOS-Extended programs use the DOS Protected Mode
 Interface (DPMI) in order to get access to extended memory.
 However, the DPMI specification suggests that, in the absence of a
 DPMI host, other strategies such as VCPI or XMS can and should be
 used to get access to extended memory.  This means that the
 Quarterdeck DPMI Host (QDPMI.SYS) may not be necessary on your
 system.  If so, use QSETUP to disable QDPMI, save your
 configuration, and run OPTIMIZE.

 12. Use QEMM's Analysis Procedure to Gain High RAM

 If you're not using QEMM's StealthROM feature, you may still be
 able to us  e small amounts of address space that are marked as
 reserved by the System ROM, but which are acutally unused.  The
 Analysis procedure is documented in the QEMM manual.  You should
 not need to perform an Analysis if you are using StealthROM, which
 typically gains much more High RAM.

 13. On DESQview/X Systems with 8514/A Graphics Adapters, Use VIDRAM

 If you have an 8514 hardware-compatible video card and DESQview/X,
 you can use VIDRAM without disabling graphics!  This is because
 8514/A graphics adapters do not use the address space that VGA
 adapters do, and because DESQview/X specifically supports the 8514
 adapter.  This can create DESQview/X windows that can provide
 64K-96K of conventional memory.  Note that if your 8514 card
 requires a driver then it is not likely to be hardware compatible
 and that this hint may not be successful.

 First, add the VREMS to the QEMM386.SYS line in the CONFIG.SYS
 file.

 DEVICE=C:\QEMM\QEMM386.SYS RAM VREMS

 Then, type the following line before you enter DESQview/X.  You
 may choose to add this line to your AUTOEXEC.BAT file, or to any
 batch file that starts DESQview/X:

 C:\QEMM\VIDRAM ON

 This line will activate VIDRAM and extend conventional memory.
 When you start DESQview/X, it may report "GRFVGA.DVR does not find
 the correct video adapter".  You may safely ignore this message;
 DESQview/X will function properly.

 14. Reduce the overhead of your operating environment.

 DESQview and DESQview/X's Setup programs contain some settings
 that may allow you to squeeze an extra few K of memory out of a
 heavily loaded system, at the potential cost of some speed or
 performance.

 "Common Memory" is memory used by DESQview and DESQview/X to
 manage its windows, and the amount you need is usually
 proportionate to the number of windows you open, and the amount of
 text you intend to transfer with DESQview's Mark and Transfer
 feature.  The default (and minimum) value under current versions
 of DESQview is 20K, and should permit the transfer of several
 screen's worth of data and several windows open simultaneously; if
 your common memory setting is higher than this, you may wish to
 reduce it.  Under DESQview/X, the default value is 32K; this may
 be reduced by a few K to eke out an equivalent amount of window
 memory.

 "DOS Buffers for EMS" (under DESQview) or "DOS I/O Buffer" is
 memory used by DESQview to manage file operations into expanded
 memory.  The default value is 2K under DESQview, and 8K under
 DESQview/X.  Users of QEMM who are not on a network can set this
 figure to 0K with no loss of performance.  The value of this field
 can affect the speed of disk access; however, it is rarely
 worthwhile to choose a value higher than 10K or 15K.

 If you wish to throw away a few DESQview features, you can
 probably scrimp a few more K from the Setup program.

 On the Keyboard option, you can save as much as 12K if you tell
 DESQview that you don't wish to use the Learn feature.  This will
 disable DESQview's very useful macro system.

 On the Video Monitor option, you can save anywhere from 0K to 16K
 if you tell DESQview that you don't wish to display text and
 graphics at the same time. This will disable DESQview's Video
 Options menu, prevent graphics programs from being seen when they
 are in background, and prevent virtualization of graphics. You can
 save another 2-9K by choosing 0 for "What Display Adapter do you
 have?".  This causes DESQview not to load a video driver.  This
 will keep DESQview from saving and restoring graphics screens or
 virtualizing graphics.

 On the Performance option, you can save 2K by setting the "Manage
 Printer Contention?" field to its default value of N. This means
 that DESQview will not intervene to prevent two programs from
 printing at the same time.

 On the Network option, you may disable the network support, or
 decrease the size of the buffer.  This support is needed only for
 certain network-specific program, and not for most normal DOS
 applications that are merely run off the network.

 The amount of memory you will save will be about 5K plus the size
 of the buffer reserved in the second field.  Unless you know that
 you need this service, you should try running without it and
 seeing if you have problems without it that you do not have with
 it.  You may also try decreasing the size of the buffer.  The
 default is 8K.

 ******************************************************************
 *      Trademarks are property of their respective owners.       *
 *   This and other technical notes may be available in updated   *
 *     forms through Quarterdeck's standard support channels.     *
 *          Copyright (C) 1996 Quarterdeck Corporation            *
 ******************** E N D   O F   F I L E ***********************