OS/2 Shareware BBS: 8 Other/08-Other.zip/warpst04.zip/WarpPerf.TXT

Text File | 1995-05-25 | 44KB | 792 lines

Performance Tuning OS/2 Warp




























Ron Cadima
ISV Development Assistance
IBM
Boca Raton, FL



About This Document:

This paper makes the assumption that the reader is familiar with OS/2 Warp and many
of the technical terms in use by the computer industry. It presents general and specific
tuning information for a computer that will have or has had OS/2 Warp installed. It
starts by taking the reader through some general system setup considerations with
regard to processor type, disk type and the amount of memory in your system. Next it
goes into detail with respect to CONFIG.SYS statements that should never be
modified and those that can be modified to help improve system performance. System
Settings and Desktop Settings are covered next. Finally Appendix A presents
measurement information about how much memory is used for different functions and
products.

Some terms and phrases that will be used in this document are as follows:

Warp     - OS/2 Warp Version 3.0 both the version that is used with Windows already
installed on your machine and the version that includes the WIN-OS/2 support.

OS/2      - Refers to the OS/2 Warp Version 3.0 product and its capabilities.

System - a generic term that refers to computer with an operating system and
application programs installed on it.

Memory - The amount of physical memory or RAM ( Random Access Memory) that is
installed in the computer or used by a particular function.

Working Set - Is the amount of physical memory used by the operating system or a
program to perform a specific function or group of functions. It includes all code
and data.

FAT       - File Access Table file system.

HPFS    - High Performance File System.

Desktop- Sometimes referred to as the Workplace, this means the Workplace Shell
        feature of OS/2. The Workplace Shell is the part of OS/2 which controls how you
        OS/2 systems appears on your computers video screen.






Trademarks:

IBM Corporation:
OS/2 Warp Version 3.0
DB/2
LAN Server 4.0
Personal Communications/3270
BonusPak

Microsoft Corporation:
Windows 3.1                     Excel
Windows 3.11                    Word For Windows
Windows for Workgroups 3.11


General Setup Considerations:

There are some basic considerations that need to be made about the computer that
you will  install Warp on. They break down into 3 elements: processor , memory and
disk.

In most cases the processor that you have in your system has a minimal impact on
performance compared to the amount of memory and the speed of the disk. The only
real considerations to make with respect to processor are its age. You should avoid
386 and 386SX processors. You want processors that can be upgraded and those
that support instruction caching sometimes referred to as Level 1 or Level 2 cache.
There really is no optimum level instruction cache size. More instruction cache is
usually better than less. The only real determinant should be costs.

Memory, also called RAM,  is a different story. Without enough memory your system
will run slow.  If you cannot afford to buy memory for your system, then you must
manage the things you install. You should only install fonts, device drivers, objects
and applications that you will actually use. You may think that just because you have
not started an installed application, it is not using any memory. This is not always the
case. Many newer OS/2 applications will register classes and objects with the
Workplace Shell or add items into path statements, set statements and the like. Many
of these things will cause memory to be used even when the program is not running.
In some cases, the program will require special device drivers be installed which will
also use up memory.

Other things that affect memory usage are disk caches, CD-ROM caches, multimedia
support and buffers. The important factor to consider for the disk cache, is that it is
designed for general use. Since most systems are not general use, the disk cache
should be tuned to the specific system environment to optimize memory usage. We
will discuss the disk cache considerations in more detail when we look at the file
system options.

Probably the most important piece of hardware on your system is the hard disk.  It will
affect the performance of starting your system, loading applications, the speed of
applications,  and the general performance of your system.

It is best to have a disk subsystem which uses a bus-mastering type of adapter. Many
SCSI devices and some of the PCI devices have this capability. These types of
devices allow for multiple requests to be sent to the disk device to be processed rather
than just one command or function at a time. They also allow what is called scatter /
gather capabilities. Without bus mastering, data that is transferred between the
computer's memory and the disk must be in contiguous memory, one byte after the
other. With bus mastering, the data does not have to be contiguous and does not have
to be on a 64K byte boundary. Bus-mastering relieves the system of a lot of overhead
and therefore performs faster in actual usage , although  you will see little or no
difference when running benchmarks. When benchmarks are being run, they tend to
be the only thing running in the system and therefore are not competing for memory or
other systems resources. Also, buffers, data and code tend to be in contiguous
memory and therefore do not require the capabilities that Bus-mastering has to offer.

When the memory in your system is over committed, that is, the operating system and
the programs you are running need more memory than is physically available in your
computer, Warp will page, or swap, executable portions of the operating system and
programs, and data that has not been accessed for a while to the disk in order to
make room for the needed code and data. In this instance, the disk is the single most
important factor in your system with respect to performance.

Another consideration with regard to the disk is whether or not it has its own caching.
If it does and your applications perform mainly sequential disk access, then you can
reduce the size of your software disk cache.  Hardware disk cache will have little or no
effect when the programs perform random disk operations. The hardware cache will
improve the performance of starting the Warp operating system and the applications.


File Systems:

OS/2 supports two file systems for use on your hard disks: FAT and HPFS. No matter
which file system is used, there are some basic considerations. You need to install the
file system depending on which operating systems will access the data. If you plan to
boot  a DOS or Windows system natively, then any data that will be accessed must
exist on a FAT disk partition. If you will only be running DOS and Windows
applications in a Warp VDM ( Virtual DOS Machine ), then the file system can be
HPFS or FAT.  Also, when accessing a file on a server, and the server file system is
HPFS, you do not need to install HPFS on your local client machine. HPFS only needs
to be installed on a computer when a partition on a local hard disk is formatted as
HPFS.

The amount of memory you have in your machine should affect the decision about
which file system to use. When HPFS is installed, it requires a minimum 200 to 250k
of working set, plus the space allocated for its cache. That is is, it reduces the amount
of physical memory that is available to programs by 200 to 250K. This is a large
amount of memory and is the main reason why FAT is used when Warp is installed on
a  system that contains 4 MB of physical memory..

Regardless of which file system you select, you need to plan for future requirements:
How will maintenance and fixes be applied? Where will applications be installed?
Where will data reside? etc. I recommend that when you set up your hard disk, you
create a minimum of 3 partitions. One will be for the operating system(s), one for your
applications and static data files, and another for dynamic data files and temporary
files.  Decide whether you want to use Boot Manager or Dual Boot. If you select Dual
Boot, then OS/2 must be installed with the FAT file system.

For temporary files, it is better to have them preallocated and reuse them rather than
create and destroy them every time. Extending a file can be almost twice as slow as
just writing to a file. Also, if you reuse files, it will definitely reduce the fragmentation in
your disk directories. These types of files can be the ones allocated by programs that
you run, or can be files you create to pass information between systems, or processes
in your local system.

Now let's look at some specifics with regards to the two file systems.

FAT:

FAT is best suited for disk partitions that are 80 MB or less in size or that have a
limited number of files installed. Usually, 256 files is a good target, with up to 500
acceptable.  The number of files become important because FAT files are allocated
based on a cluster size. The cluster size is determined by the size of the disk partition
and can be 2K, 4K, 8K or higher. Since most file sizes are not an exact multiple of the
cluster size, disk space gets wasted. For example, installing DOS, Windows and Warp
on a 100MB partition resulted in 2.2 MB of disk space being wasted. A 100MB
partition will use a 2K cluster size. If you were to use a 540MB partition size, then your
cluster size would be increased to 16K and a significantly greater amount of disk
space will be lost.

When Warp is allocating space for a file in a FAT partition, it will look for the largest
available free space area to write the data or create the file. If lots of files were created
and deleted, or expanded, these free space areas become smaller and smaller and
are spread out over the disk. This is referred to as fragmentation. When a file is stored
in many areas on the disk, it takes longer to read that data simply because the disk
head has to do more seeking.

The FAT file system disk cache is defined by the DISKCACHE= statement in the
CONFIG.SYS file. New in Warp is the "D" designation for the size of the disk cache.
Each time Warp is booted, it will allocate space for the disk cache based on the
amount of physical memory that is installed in the system. If more than 8 MB is
installed, 10% of the physical memory will be used for the disk cache up to a
maximum of 4 MB. Based on what applications and support you install in your system,
this may be too high and cause you to over commit your memory. If there is not a lot of
disk work done on your system, or you are using DB/2 or HPFS, then you should
reduce the size of your disk cache. A number between 128 and 256K is sufficient for
most systems. On a 4 MB system, we set the disk cache to 48K.

The minimum cache size that can allocated is 32K while the largest is 14.4MB. Even if
you only use HPFS on your system's disk drives, the FAT cache, along with lazy
writing will be used for diskette drives. In this case, you would want to set the minimum
FAT cache size of 32K.

In conjunction with the cache size, you should also set the cache threshold. This
determines which records being written or read will be placed in the cache. The default
is a record size of 2K. What this means is that a record whose size is greater than 2K
will not be placed in the cache and will have to be read from the disk device if it is
accessed again. The 2K default is good for cache sizes that are less than 128K.  If
your cache size is 128K or larger, increase this value to at least 16 and preferably 32.
More detail about this parameter and the DISKCACHE= statement will be given in the
section on CONFIG.SYS.


Some additional items for improving performance using FAT are:

* Group files by usage, the most used files first, and least used files last.
* Group files based on whether they are static or dynamic. All dynamic and temporary
        files should be placed in a separate partition.
* If possible, place all temporary files in a single directory.
* If possible, permanently create temporary files and reuse them.
* Only create directories that are really needed. The fewer number of directories you
        have to search, the faster your search will be.
* Defragment your partitions after installing new applications, deleting files or applying
maintenance and fixes. Most DOS defragmentation programs that are aware of
hidden files can be used.  You may also wish to look at J&J Utilities for OS/2
produced by J&J Computer Consulting, and the different GammaTech utilities
produced be SofTouch Systems, Inc. These utilities are aware of EA files and tend
to be saver to use.


HPFS:

HPFS does away with some of the concerns that are prevalent with FAT. Files are
allocated based on a 512byte granularity instead of a cluster size, therefore
fragmentation is greatly reduced. Also HPFS is especially efficient when handling
large partition sizes, > 100 MB, and large numbers of files, > 500.  One thing you
should look out for is to not allocate more than 5000 files in a sub-directory or
directory. When you exceed 5000 files, you will start to degrade performance. The
HPFS file system shipped with the Warp product has a cache limit of 2 MB. There is
no such limit when using the HPFS386 file system that comes with the LAN Server
products.

With HPFS, you specify the cache size and the caching record threshold size in the
IFS statement in the CONFIG.SYS file. As with FAT, you should specify the size of the
largest record that can be placed in the cache (cache threshold value). The /CRECL
parameter is used to define this by specifying a number in terms of K bytes.  32K is
usually a good starting value. The range can be from a low of 2K to a maximum of 64K
and must be expressed in increments of 2K. If it is not, the value will be rounded up to
the nearest 2K boundary.

As mentioned earlier, the big drawback to HPFS is the amount of extra memory that it
requires. Even if there is no HPFS partition on your system, it will cost between 200
and 250K in working set memory, as well as the space for the HPFS cache.  If you are
installing Warp on an existing DOS and or Windows system, you should not install
HPFS. When your system is up and running, you can check the working set of your
system. If there is enough free memory and you wish to create a HPFS partition, then
you can use selective reinstall to install the HPFS support. Remember that any data
stored in the HPFS partition can not be accessed if you boot your machine under DOS.

Another advantage of HPFS over FAT is in the area of extended attributes (EAs).  EAs
are data attached to a file and used to provide information about the file they are
attached to.  For example, the name of an object that appears in an OS/2 folder or on
the OS/2 Desktop is stored in EAs. In HPFS, EAs are part of the HPFS file control
block which is read when the file is open. In FAT, EAs are stored in a separate file in
separate clusters and require additional I/O to access them, and are therefore slower.


System Tuning:

Before covering OS/2 system tuning let's  review the concept of threads and how they
are used in OS/2. Every program that you run on an OS/2 system will process as one
or more threads. All programs, DOS, Windows and OS/2 use a minimum of one
thread. Each thread executes at a given priority.  The priority is used by OS/2 to
determine which thread gets to run when more than one thread is ready to run. The
highest-priority thread that is ready to run will be the one dispatched by the system
and given time to run. It is given what is referred to a "time slice". This is a set period
of time during which a thread is allowed to run. After this time has expired, the
highest-priority thread that is ready to run will be given it's own time slice in which to
run. If the same thread still wanted to run, and it was the highest-priority thread, it
would receive another time slice to run in.

OS/2 programs usually run at normal priority, which is 200. Under program control, the
program can change its priority to be server class, 300, or time-critical, 800.  It can
also change its subclass priority between 0 and 31. A thread that has priority 200 and
a subclass of 15 has a higher effective priority than a thread with priority 200 and
subclass 0, and therefore runs first. All DOS and Windows applications always run at
priority 200.  In OS/2 Warp, we have added the capability to define the subclass
priority for DOS and Windows applications.  Care should be taken when using this
subclass priority since it may cause other programs to run slower or generate errors in
the case of communication applications that do not get the subclass boost.

Warp will give OS/2 threads a priority boost for specific types of functions and states.
A  priority boost means that the priority of the thread is changed for a given time slice
to give it higher priority than other threads. This allows these threads to process more
quickly and therefore improve their responsiveness to the user.  Following is a list of
priority boosts that can be given to a thread. They appear in descending order.

Disk I/O:
When an interrupt is received stating that a disk operation has completed, the
thread that processes this state will receive a priority boost for one time slice to
process this interrupt. This applies to threads whose process has foreground
focus. Foreground focus means the process that owns the window that is
highlighted on the computer screen.

Starved:
In the CONFIG.SYS file, there is a statement MAXWAIT=3. The number 3
specifies how many seconds a thread can be in the ready-to-run state without
having received time to run. If a thread had been waiting to run for 3 seconds, or
whatever value is specified in the MAXWAIT statement, its priority would be raised
to give it an opportunity to run.

Keyboard:
        This is a boost in priority given to a thread when it is interacting with the system
        keyboard.  Basically, it is for accepting typed in data.

Foreground:
        This is a priority boost given to all threads of the program that owns the active
        window on the OS/2 screen, the one that is highlighted.

Windowed:
        Threads which have windows showing on the display will also receive a priority
        boost when drawing or writing into that window.

When a thread is in more than one of these states, the system will combine the states
and give a priority based on the combined states.

For DOS and Windows applications, the Foreground, Windowed, and keyboard states
do not apply. The routine that handles the mouse or keyboard interrupt will receive a
boost in priority to handle the interrupt, but the application does not receive a priority
boost. If the DOS Setting INT_DURING_IO is specified, a second thread is used to
handle the I/O interrupt, and that thread is given an interrupt boost.

Idle class is the other priority class that exists in OS/2. This priority level runs only
when nothing else in the system wants to run. Threads in this class will not receive
any of the state boosts. If DOS and/or Windows applications are being run, then you
should avoid the use of threads that run in idle class because they may never run but
will take up system space.

Now let's look at specific things in the CONFIG.SYS file that you can change to affect
the performance of your system. First we cover those statements that you should NOT
modify unless you have a system which has a special use, such as a process control
system. An example would be a system used to monitor a manufacturing machine or
chemical process, where timing and response time are critical factors.

PRIORITY_DISK_IO=YES
        This allows the application that has screen focus to receive a priority boost when
        it's disk operation is complete. This applies to the first time slice given to the thread
        after the disk operation is complete. After the time slice, the state is reset for the
        thread and the priority boost removed.

MEMMAN=SWAP,PROTECT
Allows OS/2 to swap program instructions and data to disk when more memory is
needed than is physically available in your computer. If you do not specify SWAP,
you will need enough physical memory in you computer to hold all the program
instructions and data that OS/2 and your application needs to run. You do not pay
a penalty by specifying SWAP and then not needing to use it.

        The PROTECT parameter allows Dynamic Link Libraries ( DLL) to allocate
        protected memory. Protected memory is memory that is protected from being
        accessed by unauthorized programs.

You can also specify a COMMIT parameter. This forces the system to ensure that
enough physical memory or swap file disk space is available for a memory object
when it is created. Normally, OS/2 commits physical and disk memory when the
page of memory is actually touched. Specifying this parameter can significantly
increase the amount space your swap file uses on disk. You would usually only
specify COMMIT if you were developing applications or systems and wanted to
see what the maximum amount of memory and disk space that could be required
for your system.

TIMESLICE=X,Y
        This statement is not found in the CONFIG.SYS file after you install OS/2 but is
        sometimes recommended to be added. This was okay to add for OS/2 2.0, 2.1 or
        2.11 systems, but not for OS/2 Warp. In Warp, we dynamically modify a threads
        time slice based on actions that have occurred. For instance, if a thread took a
        page fault during it's time slice, we give it an extra time slice to process what is
        contained in the faulted page. We also give applications doing disk I/O extra time
        slices if the data they are reading is in the disk cache. When the TIMESLICE=
        parameter is used, none of these actions will occur. Instead, each thread will be
        given the minimum time slice of X, and its time slice will not be allowed to go
        beyond value Y.

PRIORITY=DYNAMIC
If DYNAMIC is not specified, then each thread will only run at the priority that has
been assigned to it by the developer of the code. None of the priority state boosts
described earlier will be applied.

DEVICE=C:\OS2\BOOT\VDISK.SYS
        This statement allocates a virtual disk in your computers physical memory. It is
        used for quick access to often-used files and programs. This was good for a DOS
        environment where the extra memory in your computer was not used by DOS, but
        OS/2 uses this memory, and your performance can be adversely affected if a
        VDISK is used.  It is much better to increase the size of the disk cache if you have
        unused physical memory than it is to use VDISK.

Now let us look at statements in CONFIG.SYS which you should change to help
improve the performance of your Warp system.



LIBPATH=

This tells the system where to find DLL files and printer device drivers that Warp
and applications use. Place the directory names in order of usage. The most
accessed directory should be first, the least used last.  If possible,  place the DLL
used by a program in the same directory as the working directory when the
program is running. Then, you do not need to add that directory to the LIBPATH
statement.  Also, place all directories that are on a network at the end of your
LIBPATH  statement in case the network goes down and they cannot be accessed.
When you try to access a network drive that is not active, you will have to wait for
an error time to occur before processing can continue. This can be as much as 15
seconds or longer. See the discussion of dynamic LIBPATH support later on in this
paper for additional considerations when accessing network drives.

SET PATH=

PATH is used to specify where Warp searches for executable program files, EXE,
COM, CMD, BAT, etc.  Place the directories in order of most used first, least used
last. If programs will be executed from an object on your desktop or folder, specify
the path there and not in the PATH statement. Only place directories in the PATH
statement for executable files that will be called from other programs, commands
interpreters or command line interfaces..

SET DPATH=
The same principle applies to DPATH as PATH and LIBPATH.  For resources that
applications use, place the most used directories first and the least used last.
DPATH is used to define the search path for finding data files.

BUFFERS=90
        Buffers are physical memory used to support partial sector reads and writes in a
        FAT file system environment.  They are also used to cache FAT directory entries
        and for swap file disk I/O.  Because BUFFERS are used to cache FAT directory
        entries, this number should not be reduced below 60, unless you are not using the
        FAT file system on your disks.  Reducing this number will increase the number of
        disk reads that are done to the FAT directory entries and therefore slow down your
        system.

MAXWAIT=3
        This specifies the maximum amount of time that a thread will be in a ready-to-run
        state without receiving a time slice to run in.  After this time expires, the thread
        will be given a boost in priority so it gets a chance to run.  Reducing this value to 2
        may help in systems where there are a lot of programs running, or multiple
        separate DOS/Windows programs running. Reducing it to 1 on systems where
        there is swap activity taking place can slow down the system.




DISKCACHE=D,LW,t,AC:
This is used to specify the amount of physical memory set aside to cache data that
is being read from or written to disk partitioned that are formatted for FAT. When
Warp see "D"  specified in the DISKCACHE statement it will allocate a disk cache
size from 48K to 4MB, based on the amount of physical memory you have in your
system.  If you have more than 8 MB in your system, D will cause 10% of your
system's physical memory to be used for the FAT disk cache. Instead of specifying
D in the DISKCACHE statement, you should change it to the actual amount of disk
cache space you require. If you have a system where your programs do not do
much disk I/O or where your memory is being used up by your applications, you
may want to set this value to 128.  Also, reduce this value if you are using the DB/2
product or any other product that provides its own disk data caching.  If you have
system that has lots of memory, then you can specify a number bigger than 4MB.
The maximum allowed is 14.4 MB.

The t parameter is not defined in the default CONFIG.SYS file. It defines the
cache threshold for records that go into the cache.  The default value is 4. This
means that any record that is 4 sectors or less will go into the cache, while those
greater than 4 sectors will not. If your disk cache size is 128K or larger, add this
parameter to the disk cache statement.  If known, set this value to the largest
record size used. Otherwise, set the value to 32. The range can be from 2K ( 4
sectors) up to 64K. I chose 32 because it is a good starting point and is big enough
to handle most applications and program executable files.

The LW parameter activates the Lazy Write or write behind feature. This allows the
application to get control back before the data is actually written to disk.  A
separate thread will write the data from the cache to the disk when necessary or
opportune to do so.  You should always use this option, and code your applications
to open files with a cache bypass option if disk data security is imperative.

The AC: parameter is used to specify which FAT directories should be checked at
system boot time to see if they were left in a unpredictable state when the system
was last powered off. This usually occurs when the power is lost to your machine
and you had not done a Shutdown or Ctrl-Alt-Del key sequence prior to losing
power. The disk directories specified here will have CHKDSK run against them to
clean up any lost files or abandoned clusters.

SWAPPATH=d,r,s
SWAPPATH specifies where code and data pages are swapped to on disk when
more physical memory is needed than is available in your system.  The d
parameter represents the path where your SWAPPER.DAT file is located.  For
systems which have multiple partitions or multiple disks, this should be placed on
the most used directory of the least used disk.  Also, try to physically locate the
swap file on the disk based on its usage. If you are doing a lot of swap activity,
place the swap file at the start of the disk.  If is it rarely used, place it at the end.

The s parameter specified the size that the swap file is initialized to when you start
your Warp system.  Make this large enough so that it does not have to grow in size
while you are running your programs. You should perform your normal computer
functions and look at the size of the swap file when you have the most activity.
Then set the value of the s to this size in the CONFIG.SYS file.  If you are using
the FAT file system, IPL your system under DOS, delete the SWAPPER.DAT file,
defragment the disk partition where the swap file will be located, and then  IPL your
OS/2 system. This should keep your swap file from getting fragmented.

The r parameter specifies the amount of free space that must be in the swap file's
drive. The default for this value is adequate and only needs to be changed if you
want to be warned earlier about a possible out-of-memory situation.

THREADS=
THREADS defines how many threads the system will be able to use.  One page of
resident memory is need for approximately every 32 threads that are defined. This
memory will be allocated at the time the system is booted.  As a minimum, you will
need 80 threads to support the base Warp system and 3 or 4 OS/2, DOS and or
Windows applications.  The system will support up to 64000 threads, but typically
you will not have enough memory in your system to support more than 300 to 500
threads.  18 threads are required for LAN Server 4.0, and 12 for Personal
Communications/3270.  You will need an additional 2 threads for each Personal
Communications/3270 session that is started.

        To calculate the number of threads that you will need in your system, use the
        formula 54+(2xN)+10 where N is the number of programs that you will run
        together. If the program requires more than 2 threads, add in the additional
        threads.  This will insure that you have enough threads in most cases.

To determine how many threads you are using at any given time, run the PSTAT
command from an OS/2 command line. This will show all of the processes that are
running on your system, as well as how many threads each process is using. The
output is quite long, so you may want to redirect it to file.

Additional CONFIG.SYS Considerations

You should only install the devices drivers that your programs actually need to run.
Do not install extra communication, printer, video or device drivers if they will not be
used.  Below are a list of device drivers and virtual device drivers that are normally
found in CONFIG.SYS and that may not be needed.  ( Virtual device drivers are used
to support DOS and Windows applications and usually have a V at the beginning of
their name.)

VEMM.SYS Used to support Expanded Memory use in DOS and Windows programs.

VXMS.SYS Supports Extended Memory in DOS and Windows applications.

VDPMI.SYS Supports the DPMI memory access and is required to support all
        Windows applications.

VW32S.SYS Supplies support for the WIN32S Windows APIs.  Not needed for
         Windows programs that do not use WIN32S APIs.

IBMxFLPY.ADD x will be either a 1 or a 2. 1 is used for family 1 machines and 2 is
        for MCA ( Micro-Channel Architecture ) machines.  You do not need both.

XDFLOPPY.FLT This is required for reading diskettes which are written using  the
        XDF ( Extended Disk Format ) format.  These are usually OS/2  and PCDOS 7
        installation diskettes, printer and video driver diskettes and possibly CSD diskettes.
        The Warp Install and Disk 1 diskettes do not use the XDF format.

COM.SYS and VCOM.SYS are only required if you will be doing serial or async
        communications.

If you use the selectable CONFIG.SYS option in the Archive and Retrieve feature of
Warp, it is possible to create multiple CONFIG.SYS files which will contain different
device drivers based on your needs.  For example, you could create one
CONFIG.SYS file that is used for maintenance and installation.  This one would
include the XDFLOPPY.FLT and both IBMxFLPY.ADD drivers plus additional threads.
Another CONFIG.SYS used for normal processing could have these device drivers
removed and a lower number of threads.  When maintenance has to be applied to the
system, or some additional new products installed, you could boot the machine with
the Archive and Retrieval menu active and select the proper CONFIG.SYS to be used.
An extension of this would be to archive the CONFIG.SYS and the OS/2 INI files and
select those to apply maintenance.

System Settings

Let's look at some of the System Settings and Desktop settings that can be tuned to
improve a system's performance.  In the System Setup Folder there are many utilities
that are available.

Spooler:
The drop-down menu of the Spooler Icon in the System Setup folder,  provides an
option to disable the spooler. This can be done without problems when only one job
will be active on your printer at a time. This will save a little bit of memory and one
process and thread in your system. If you have a dedicated print spool machine, then
you should raise the priority of the spooler to it's highest point. For non-dedicated print
spool systems, the priority should remain at the default. You would only increase this if
(for example) you raised the subpriority of a DOS session and wanted to print
documents while running the DOS session.  In this case, you would want to make the
priority of the print spooler the same as the DOS session.

Schemes and Color Pallet:
You should use solid colors and  avoid the use of bitmaps for desktop and folder
backgrounds. These particular options use more memory and require more processing
time to display them.

Sounds:
Deselect the System Sounds options, unless you like the noises when opening and
closing your folders. It costs between 250 and 300K in working set just to hear the
noise.  An additional 40K or so of working set can be saved by executing
DINSTSND.CMD in an OS/2 command session.  This will unhook the system sounds
from the OS/2 desktop. To get them back, you would execute INSTSND.CMD.

Font Palette:
Only install the fonts that you will actually use in your system.  Also, try not to mix fonts
in folders or on the OS/2 Desktop.  If you do, you will be using extra memory. Outline
fonts tend to be a little smaller in terms of memory than bitmap fonts and once they
are in the cache, they perform just as fast.

WIN-OS/2:
When defining a Windows program, select common sessions and make DDE and
Clipboard support both private.  If floating-point is used in your Windows applications,
use the enhanced run mode for Windows. This can give as much as a 20% gain in
performance.  Also, if you have a Windows application that you always run, it  is better
to start it via the Startup Folder than to use the Fast Load option and start it from the
Desktop.  When you migrate windows applications, install or add Windows programs
to you system, ensure that the run mode for these is the same as the common session
run mode.  If run modes are different, then you will have two separate Windows
sessions running even though you stated that a common session is to be used.  If you
get errors such as unable to allocate buffers or other resources when using a common
session, try using enhanced run mode for that session if is standard. This will usually
clear up these when there is enough system memory available.

System Setup:
Disabling the Animation and Print Screen option can save a little in code path, number
of program instructions executed,  and memory.  Setting the System Logo option to
none can save some time when loading applications that check this parameter to see
how long to display their applications logo.  The type-ahead option will use a little more
memory.  When selecting screen resolutions, remember that the higher the resolution,
the more memory that is used.  Very high resolution and color support can require 100
to 200K of physical memory.

Mouse
Mouse pointers are basically bitmaps. The amount of memory used will be affected by
which mouse pointer style you choose. If you activate the comet cursor, this will cost
additional memory and processing time whenever the mouse is being used.

Desktop Settings:
Desktop settings are selected by choosing the Settings option on the Desktop menu.
Choosing Automatic Lockup will cause extra code path and processing time to occur.
Normally this is very minimal, until the timeout value expires.  Then you are looking at
about 40 to 50K of working set.

If you select Create Archive on system restarts, this will slow down your system's boot
time.  You want to set this option only when you have changed your desktop and/or
configuration and want to save it.  Once it has been saved, turn this option off.  You
can get to the Archive Retrieve menu screen when you boot your machine by using
the ALT+F1 key sequence.


Conclusion

All the bells and whistles, neat features, applications and devices come at a cost.
They all cost disk space, they all use memory, and they all have the potential for
slowing your system down.  To minimize this, plan ahead.  Decide what the system
will be used for and what your future uses will be. Then, set up the system
accordingly. Install only the things that you are actually going to use and need. Ensure
that there is a match between the software you install and the hardware you install it
on. If an application or feature cost more memory than you have, either don't install the
feature, or get more memory for your system. Finally be creative and logical. You can
set the system up with different configurations and different support, defined to
optimize performance based on the particular functions you perform and applications
you use. Become aware of what Warp has to offer and use it to your advantage.
Appendix A:

The memory measurements results presented here are for planning purposes only.
There is no guarantee, implied or otherwise, that you will reproduce these numbers
exactly on any other system.  Measured results will change based on the hardware
configuration of your computer, and what software is installed in the system. If the
hardware or software configuration changes, the results will also change.

All numbers are presented in megabytes of memory unless otherwise noted and
indicate all  the physical memory that is used to execute a given function. This
includes data, the Warp operating system and programs..

All measurements were made on a PS/2 A21, with 26MB of memory, VGA video,
ESDI disk, mouse, keyboard and 16/4 Token Ring adapter.  HPFS and Multimedia
support were not installed in the base system.  The CONFIG.SYS file was modified to
be equivalent to how it would look on a 4 MB system. DISKCACHE=48,
THREADS=96, and no IFS statement for HPFS.

Memory Requirements:

  Function                      OS/2 Warp               OS/2 Warp
                        For WIndows     With WIN-OS/2

Open System Folder           3.6 MB                    3.7 MB
Open Command Prompts         3.5               3.6
Start a DOS Session          4.5               4.6
Exit the DOS Session         4.3               4.3
Start a Windows Session      6.3               6.0
Exit the Windows Session     5.3               5.3
Open Productivity Folder     3.5               3.6
Start Enhanced Editor        4.5               4.6


The numbers for DOS and Windows sessions are for full-screen sessions and
therefore include the working set memory for switching back to the Warp Desktop to
stop the measurement process.  Following are numbers for starting a DOS session in
a window and the Windows PROGMAN support in a window, also referred to as a
seamless session.

  Function                      OS/2 Warp               OS/2 Warp
                        For WIndows     With WIN-OS/2

Open DOS Window Session              4.16 MB                  4.15 MB
DIR Command in DOS Window            3.00                     3.00

Windows Session with Standard Run Mode and Public DDE and Clipboard Support

Start PROGMAN        6.17 MB                  5.84 MB
Open Folder Main     3.51                     3.50

Windows Session with Enhanced Run Mode and Private DDE and Clipboard Support

Start PROGMAN        5.86 MB                  5.69 MB
Open Folder Main     3.39                     3.35

The above numbers show that how you set up your session can have a significant
impact on the amount of memory used.

All above numbers are the amount of total memory used for the particular function.


The next series of numbers shows how much memory is required when the particular
support is is installed or activated on your system. These number are presented as
Kilobytes ( KB ) in size.  For example, Save Desktop costs 300KB in working set
memory. So, if the desktop was being saved while the System folder was being
opened, 3.9 MB of memory would be required instead of 3.6. The numbers below are
in addition to those above.

Support         Additional Working Set Memory

Multimedia
                Device Drivers           50 KB
                Desktop Folder and Objects      100
                System Sounds           40 - 300   ( Inactive - Active )

Save Desktop                    300

HPFS                    200 - 400  ( No HPFS Partition
                                                  Defined, and 64 K cache )
XDF Support                      50
Personnel Communications 3270
                Support not started     <20
                Support active
                      Minimum           300  ( Single session and does not
                      Maximum           450     include connection protocol )
TCP/IP                  500  ( Base support )
        This is for the Device Drivers that are installed with the BonusPak.

Lan Requester 4.0               1 MB
                Device Driver and Setup 700 KB
                Requester Active300

                Default install for Token Ring including LAN Messaging support.

STACKER 4.0                     150 KB
 ( Stack Storage and Communications, San Diego, Ca.)