
                         WINDOWS95 -Virtual Memory

                 An Interim Report  (c) 1995 by Jeff Marchi


  The development of WIN95 has been moving forward at a furious pace these
  last couple of months.  The beta testers have been getting new releases at
  a rate of one to two a week  .  A number of problems have been resolved as
  resource usage has been enhanced and conventional memory usage greatly
  reduced.  More fixes and internal enhancements are in the works according
  to Microsoft.  On  March 6, 1995 the Beta 3 version was completed which
  led to the Pre-release program in which 400,000 additional people are
  receiving copies of the product at a cost of  $30-$35 each.


  Resource and Conventional Memory Usage Improvements

  Resources

  With the release of Windows 95-Build 345, the product got a significant
  boost in resource availability.  People have been reporting on the CIS
  beta forum that they are now seeing over 90% free resources.  I did a test
  to see what percent resources would be free after running a suite of
  applications.  I was running Ecco, Winpost, MS Office, Logimouse, Wave
  Rider, Procomm for Windows, Resource Monitor, Kfree, 2 DOS prompts,
  Procomm's Fax App, 2 on screen notes (separate items on task bar),
  cardfile and Norton Editor.  14 different tasks and I had 60% of resources
  left. Normally at that point with WFWG 3.11, I would have about 25% left.
  If I start Word or Excel I lose another 10-12%.  The remaining 60% that I
  had left was the result of USER  being at 60% and GDI resources around 80%
  at the time.

  The report is that Microsoft is now working on reducing the amount of USER
  resources required under Windows so that more will be freed up in the final
  release.  They will be using more of the Windows class structure to the
  32bit heap after Beta 3 ships resulting in even more resources being
  available. This will allow you to run more separate Windows applications at
  one time.  It appears that resource problems are becoming a thing of the
  past.

  Conventional Memory

  Conventional memory usage in the Windows virtual machine (VM) has been
  dramatically reduced.  With the Windows for Workgroups 3.11 version of
  Windows I had less than 200K of  free memory in the Windows VM, and most of
  the time it was below 120K.  With Windows 95 I now have 540K of free
  conventional memory.  Prior to the end of February even WIN95 only showed
  about 175K free.  About the same time as the release of build 337 free
  conventional memory shot up to over 500K. I wasnt keeping track of
  precisely which build accomplished the break through, so I cant be
  completely certain which build was actually successful.   I have tried to
  find out if the program used to calculate this number is inaccurate but have
  been unable to find anyone at Microsoft that really knows what has changed.
  I have attempted to run a large number of simultaneous programs using a
  combo that caused out of memory errors with earlier builds of WIN95.  I have
  been unable to duplicate the out of memory error, so it does appear as if
  the change is real.

  Many of the areas we took for granted as critical issues for setting up a
  system under Windows have changed dramatically. It will no longer be
  necessary to discuss the size that the swap file should be, or how much
  cache should be allocated with Smartdrv, these two options have really
  disappeared with the advent of WIN95, they are hidden under the covers and
  allocated dynamically. This has both a good and a bad outcome.

  Swap File Changes

  Swap file usage has changed dramatically in Windows 95.  You no longer
  need to worry about setting a swap file size or making it permanent or
  temporary.  The 386 Enhanced Icon is gone from Control Panel!
  Configuration of the swapfile is  now handled dynamically by Windows.
  Below are the only settings you can adjust if you want to manage virtual
  memory.  These options are found in Control Panel/System. Windows will
  automatically create a swap file as needed, move it to another drive, if
  you choose, and permit you to limit it's allocation, or disable it
  completely!  There is a parameter in SYSTEM.INI that specifies the paging
  drive.

  device=*dynapage
  PagingDrive=M:

  An important detail, however,  is that I didn't choose drive M for the
  swapfile.  It was automatically selected by Windows, probably  because it
  was the first drive on my system that actually had enough room for a swap
  file.

  One interesting aspect of swap file management is that the swap file
  continually expands as you run more programs.  This results in making it
  always appear as though all your original available memory is present for
  use.

  Simply shutting down applications doesnt immediately reduce swap file
  usage.  In order to reduce the allocated swap space you need to close down
  most running applications, or wait a lengthy period when you are running
  fewer applications. Windows is then able to reorganize the swap space and
  reduce its size.  The swap file is used from the top down and it is
  during those idle periods where it can reorganize its space. Otherwise it
  will have large holes at the bottom and will not be able to reduce the
  overall size because there is data present at the top end.  I have found
  that the quickest way to reduce its allocation is to shut down all
  running applications and just wait a minute. This will allow Windows to
  reduce the swap down to the 4-6meg range.  On my 16meg system I have found
  the swap expanding to over 20meg, leaving very little free disk space on
  my C: drive even though there is very little is running.


  System Hardware Resources

  Another major change that will occur when WIN95 ships, is in the area of
  sleuthing usage of IRQs, DMA addresses, I/O addresses and memory, can be
  found in the Computer Properties screens.

  IRQ Usage

  I have selected IRQ's in the following screen shot, and it shows all the
  IRQ's used from 0 through 8 on this page.  On the next page of this
  display it shows the higher IRQ's that are used.

  If you look closely you will see there is no IRQ5 for LPT1 or IRQ7 for
  LPT2.  This system has both printer ports, yet Windows doesnt show them
  in use.  I noticed this a few months ago, and wondered if they were just
  being ignored, as is normal with diagnostic programs, or were they truly
  not being used.  Usually you have to put loopback plugs in the ports for
  them to be tested and seen, I dont have loopback plugs but I do have
  printers plugged into them.  I contacted the Beta team and was told that
  IRQ5 and IRQ7 are no longer used to manage the ports and are free to
  reuse. As you will note, I have a Sound Blaster Pro on IRQ5.  I had held
  off on buying a sound card for this system for a long time. After finding
  this out,  I immediately put the card that was in my second system in here
  and then got a new sound card in my secondary system.


  DMA Addresses

  There is an additional display that shows the usage of DMA addresses so
  that one can tell which are free. Here is an example of we mean. As you
  can see there are only 3 DMA addresses in use on this system, so if I were
  to add a device that needed one I could easily see which ones are
  available.


  Computer Properties - IRQ Settings

  I/O Addresses

  The third display above shows usage of I/O addresses.  The selected
  portion of that display shows the addresses used by a number of the
  devices in my system.  Note the SCSI card, Sound card, Network card,
  printer and com port addresses are listed.  This sure takes the mysteries
  out of which I/O addresses are in use and which ones are free for devices
  you want to add.


  Plug and Play Capabilities

  All of these Computer Properties information screens come into play when
  you are adding new hardware. Windows is now able to sense most new
  hardware, even without plug and play motherboards and cards.  If a device
  is added that conflicts with an existing device it will show it in the
  Device Manager section of the Control Panel/System settings.  The device
  will come up showing a red circle with a line through it and indicating
  that its not usable.  Upon checking the Properties for that device,  the
  Device Manager will show the specific conflicts.  The next screen shot
  shows the Resource settings for my Always IN-2000  SCSI controller.  As
  you can see it shows the exact resources used for the device and also has
  a window that shows Conflicting devices, which in this case says No
  conflicts.


  All of these pieces of information bring much of the benefits of Plug and
  Play to all users.  You dont need to own a PnP motherboard or I/O card to
  find out you have a conflict or to be able to figure out what to do to get
  around a resource conflict.   This will make systems running Windows 95
  easier to upgrade than  ever before.


  Jeff Marchi is a San Francisco computer consultant.  He is very active on
  the CIS Win95 beta forum and is well known on both the RIME and Ilink
  Windows conferences.  Jeff is a regular contributor to WindoWatch.
  Jeff can be found at jeff.marchi@pcgfx .com ww


