COM.TXT




		 COMpanion DOS Personal Network (tm)
			     User's Guide

			Oxford House Software
			    160 Oxford Way
			 Santa Cruz, CA 95060
		      CompuServe ID:  72603,3215




Copyright (c)1994 Oxford House Software, All Rights Reserved
	
COMpanion DOS Personal Network is a trademark of Oxford House 
Software.  Other product names mentioned in this manual may be 
trademarks or registered trademarks of their respective companies and
are hereby acknowledged.

COMpanion User's Guide -- Page 2

Definition of Shareware

Shareware distribution gives users a chance to try software before
buying it. If you try a Shareware program and continue using it, you
are expected to register. Individual programs differ on details --
some request registration while others require it, some specify a
maximum trial period. With registration, you get anything from the
simple right to continue using the software to an updated program
with printed manual.

Copyright laws apply to both Shareware and commercial software, and
the copyright holder retains all rights, with a few specific
exceptions as stated below. Shareware authors are accomplished
programmers, just like commercial authors, and the programs are of
comparable quality. (In both cases, there are good programs and bad
ones!) The main difference is in the method of distribution. The
author specifically grants the right to copy and distribute the
software, either to all and sundry or to a specific group. For
example, some authors require written permission before a commercial
disk vendor may copy their Shareware.

Shareware is a distribution method, not a type of software. You
should find software that suits your needs and pocketbook, whether
it's commercial or Shareware. The Shareware system makes fitting your
needs easier, because you can try before you buy.  And because the
overhead is low, prices are low also. Shareware has the ultimate
money-back guarantee -- if you don't use the product, you don't pay
for it.

Disclaimer -- Agreement

Users of COMpanion must accept this disclaimer of warranty:
"COMpanion is supplied as is.  The author disclaims all warranties,
expressed or implied, including, without limitation, the warranties
of merchantability and of fitness for any purpose.  The author
assumes no liability for damages, direct or consequential, which may
result from the use of COMpanion."

COMpanion is a "shareware program" and is provided at no charge to
the user for evaluation.  Feel free to share it with your friends,
but please do not give it away altered or as part of another system. 
The essence of "user-supported" software is to provide personal
computer users with quality software without high prices, and yet to
provide incentive for programmers to continue to develop new
products.

If you find this program useful and you continue to use COMpanion
after a reasonable trial period, you must make a registration payment
of $58 to Oxford House Software.  The $58 registration fee will
license one network of up to five PCs, and includes shipping and
handling.  All registered users will receive the current version of
COMpanion, plus the items listed below in What Comes with the
COMpanion Package.  You can register directly through the CompuServe 
Shareware Forum.  

 
COMpanion User's Guide -- Page 3

Commercial users of COMpanion must register and pay for their copies
of COMpanion within 30 days of first use or their license is
withdrawn.  Site-License arrangements may be made by contacting
Oxford House Software.

Anyone distributing COMpanion for any kind of remuneration must first
contact Oxford House Software at the address above for authorization.
This authorization will be automatically granted to distributors
recognized by the (ASP) as adhering to its guidelines for shareware
distributors, and such distributors may begin offering COMpanion
immediately.  However, Oxford House Software must still be advised so
that the distributor can be kept up-to-date with the latest version
of COMpanion.

You are encouraged to pass a copy of COMpanion along to your friends
for evaluation.  Please encourage them to register their copy if they
find that they can use it.  All registered users will receive a copy
of the latest version of COMpanion, plus the items listed below in
What Comes with the COMpanion Package.  You can register directly
through CompuServe.

Support Policy

You receive free support for COMpanion for three months after your
first contact with Oxford House Software.  Support is offered via
mail or through CompuServe.  Please see the cover page for details.

ASP Ombudsman Statement

This program is produced by a member of the Association of Shareware
Professionals (ASP). ASP wants to make sure that the shareware
principle works for you. If you are unable to resolve a
shareware-related problem with an ASP member by contacting the member
directly, ASP may be able to help. The ASP Ombudsman can help you
resolve a dispute or problem with an ASP member, but does not provide
technical support for members' products.  Please write to the ASP
Ombudsman at 545 Grover Road, Muskegon, MI 49442-9427 USA, FAX
616-788-2765 or send a CompuServe message via CompuServe Mail to ASP
Ombudsman 70007,3536.

				  1
	      Introducing COMpanion DOS Personal Network
----------------------------------------------------------------------
Performance You Should Expect from COMpanion.........................5
System Requirements..................................................5
Product Restrictions.................................................6
What Comes with the COMpanion Package................................6

				  2
		 Basics of Networking with COMpanion
----------------------------------------------------------------------
COM Ports............................................................8
Dedicated Servers....................................................9
DESQview Multitasking Servers........................................9
Limited Bi-directional Link.........................................10
Using Switch Boxes..................................................10
Some Things to Keep in Mind.........................................10

				  3 
			     Installation
----------------------------------------------------------------------
Using the COMpanion INSTALL Program.................................12
Copying COMpanion Files to Your System Disk (INSTALL)...............12
Updating CONFIG.SYS with the COMDEV Device Driver (INSTALL).........13
Updating AUTOEXEC.BAT File (INSTALL)................................13
Setting Up Drive and COM Port Mappings..............................14
Hardware Installation...............................................14
Using the COM Finder................................................15
Verifying the COMpanion Link........................................15
Using the Flipping Cable............................................16

				  4
			  COMpanion Programs
----------------------------------------------------------------------
COMserve - COMpanion Server.........................................17
COMsetup - Customize Device Drivers and Invoke Special Functions....18
     COMerr - Output Table of DOS-COMpanion Error Messages..........18
     COMfind - Setup to Use COMfinder...............................18
     COMfree - Free a Stacker Drive Grabbed with COMgrab............19
     COMgrab - Grab a Stacker Drive on Server PC....................19
     COMinfo - Output Information Window to Screen..................19
     COMreset - Reset COMpanion Drive(s)............................19
     COMsetv - Run COMpanion Using Video BIOS Screen I/O............19
DRIVEMAP - Get Information about Drives on Your PC..................23
DRVFREE - Free a Stacker Drive Locked with DRVLOCK..................24
DRVLOCK - Lock a Stacker Drive for Use under DESQview...............24
PRTFREE - Free a Printer Locked with PRTLOCK........................24
PRTLOCK - Lock a Printer for Use under DESQview.....................24

				  5
			   Technical Notes
----------------------------------------------------------------------
DESQview............................................................25
DOS and DR DOS......................................................26
Early Bit Detection (EBD) Null Modem Connectors.....................27
Miscellaneous.......................................................28
Performance.........................................................29
Stacker.............................................................30

COMpanion User's Guide -- Page 5

CHAPTER 1:  Introducing COMpanion DOS Personal Network

The COMpanion DOS Personal Network is ideal for use in a home or 
small office with two to five PCs.  COMpanion is less expensive than 
other network options and is easy to set up using the COM ports 
already on your PC, though the server PC may require additonal COM 
ports to support multiple PCs.  Use COMpanion to share a data base or
application software, for transferring files rather than using floppy
disks, and to share printers without requiring additonal hardware.  
You also need just one backup device for up to five PCs.  COMpanion 
uses Stacker data compression to achieve faster transfers than other 
serial networks.

Before installing COMpanion, you select one PC to act as a server. 
If more than one PC is attached to the server, DESQview multitasking 
software allows the server PC to provide disk and printer access for 
up to four PCs, while simultaneously letting you run other tasks.  
Under DESQview, write access to drives on the server is limited to 
one user at a time, and only Stacker drives are supported for
writing.

Setup features unique to COMpanion help you get up and running as 
quickly as possible.  COMpanion's Early Bit Detection (EBD)
technology eliminates the need to set baud rates.  EBD technology
also allows you to use any COM port, regardless of where your mouse
or other serial devices are plugged in.  Use the COM Finder to
indicate which COM port you are using so you don't have to guess. And
if you use switch boxes or special adapters, the Flipping Cable may
save you having to buy new adapters.

Performance You Should Expect from COMpanion

From a hard disk or RAM drive, you can expect uncompressed data 
transfer speeds of 5,000 characters per second on a 4.77 MHz XT 
system, and 10,000 characters per second on any PC operating at 10 
MHz or greater.  The maximum transfer rate is approximately 11,000 
characters per second.  COMpanion uses data compression from Stac 
Electronics.  Two-to-one data compression yields roughly 50% faster 
data transfer rates over the uncompressed rates.

Performance on your system, however, is also dependent upon the speed
of disk transfers, which can be affected by the use of a disk cache
or data compression software.  Floppy disk file transfers normally
occur at one-half to three-fourths hard disk speed.

Please note that the 16550 UART does not increase data transfer rate 
with COMpanion.

System Requirements

COMpanion runs under MS-DOS and PC-DOS 2.0+ on the Intel family of
CPUs, from the 8088 through the 80x86 processors, along with 100%
compatibles.  COMpanion also runs under DR DOS 3+.

COMpanion User's Guide -- Page 6

The COMpanion drivers in COMDEV.SYS require 12K bytes of memory.  A
special minimum configuration of COMpanion without data compression
requires less than 5K bytes of memory.  The drivers can be loaded
into high memory with the appropriate software. The server program
COMSERVE.COM requires 24K bytes of memory.

Each PC to be connected with COMpanion must have an 8250-compatible
UART, which includes the 16450 and 16550 UARTs.  Please note that the
16550 does not increase data transfer rate with COMpanion.

Product Restrictions

 Network drives such as Novell can not be accessed through the 
COMpanion server.

 DOS versions prior to 4.0 will not support disk partitions greater
than 32 Mbytes, so this restriction also applies to COMpanion.

 Only one user at a time may have write access to drives on a 
server PC.     

 Only Stacker drives are supported for writing under DESQview.

 Simultaneous data transfer between two PCs running the 
COMpanion           server is not supported.

 COMserve does not run as a background task under Windows.

What Comes with the COMpanion Package

COMpanion software is distributed on both 3.5" and 5.25" low density 
diskettes. 
 
The files listed below appear in the root directory of the floppy. 
The identical files also appear in the directory COMDUP.  Use the
files in COMDUP if you encounter a problem accessing files in the
root directory.

C1-PIF.DVP          DESQview Program Information File to run 
                    COMserve using COM1
C2-PIF.DVP          DESQview Program Information File to run 
                    COMserve using COM2
C3-PIF.DVP          DESQview Program Information File to run 
                    COMserve using COM3
C4-PIF.DVP          DESQview Program Information File to run 
                    COMserve using COM4
COMDEV.SYS          COMpanion disk and printer device drivers.
COMERR.BAT          Runs COMsetup to display DOS-COMpanion error 
                    translation table on screen
COMFIND.BAT         Setup to use COM Finder
COMFREE.BAT         Free a Stacker drive on the server PC that was 
                    previously grabbed with COMgrab.

COMpanion User's Guide -- Page 7

COMGRAB.BAT         Grab a Stacker drive on the server PC for 
                    writing.  Only required when DESQview is 
                    running on the server.  
COMINFO.BAT         Runs COMsetup to display current setup 
                    info on screen
COMRESET.BAT        Runs COMsetup to reset COMpanion drives
COMSERVE.COM        COMpanion server program
COMSETUP.COM        COMpanion setup program
COMSETV.BAT         Runs COMpanion setup program using 
                    BIOS video calls
DRIVEMAP.COM        Get information about drives on your PC
DRVFREE.COM         Free a Stacker drive locked with DRVLOCK
DRVLOCK.COM         Lock a Stacker drive for use under DESQview
INSTALL.COM         COMpanion installation program
INITCOM             Default COMsetup Setup file
PRTFREE.COM         Free a printer locked with PRTLOCK
PRTLOCK.COM         Lock a printer for use under DESQview
README.TXT          Quick start guide to COMpanion

The following files are in the directory MINICOM.  These special 
minimum configurations of COMpanion do not include data compression
or support for COMgrab and COMfree.

COMDEV.SYS          COMpanion disk and printer device drivers
COMSERVE.COM        COMpanion server program

The rest of the COMpanion package includes:

COMpanion User's Guide
2 EBD null modem connectors
     1 9-pin (DB-9)
     1 25-pin (DB-25)
Mailer for connector exchange
50' cable
COM Finder
Flipping Cable
Modular inline coupler

COMpanion User's Guide -- Page 8

CHAPTER 2:   The Basics of Networking with COMpanion

COMpanion is a client-server network.  The client PC is where you 
enter commands, such as running a program.  The server PC is where 
the disks and printers are that you want to access.  As long as the 
disks on a server PC use the DOS file system, you can use the same 
DOS commands on them that you would use on disks connected directly
to your PC, such as DIR or CHKDSK.  COMpanion does not provide access
to disks on the server that are either network disks or unsupported
by the DOS version on the client PC.

A client PC will issue requests to a server PC whenever a drive
letter is used that maps to a disk on the server PC.  Printing to the
LPT3 remote printer driver will cause output to a printer on the 
server PC.

A client PC establishes connection to a server PC through the 
COMpanion device drivers in COMDEV.SYS.  The drivers are loaded with
a DEVICE line in the CONFIG.SYS file.  Normally, both the disk and
printer drivers are loaded, but you may choose not to load the 
printer driver.

You can connect a PC to up to four server PCs, one on each of the COM
ports COM1 through COM4.  One application of connecting to multiple 
servers is to perform backups to a backup device on the client PC.

A server PC provides access to its disks and printers with the 
COMpanion server program COMserve.  Without a multitasking program
such as DESQview running on a server PC, the COMserve program makes a
PC into a "dedicated server."  That is, the PC is tied up running the
server and can not be used for other tasks.  

Multitasking provides a way for up to four PCs to share a server PC's
disks and printers.  To get the benefits of multitasking with 
COMpanion, you must purchase and install both DESQview and Stacker
software packages.  DESQview provides multitasking of COMpanion
servers, and Stacker compressed drives allow COMpanion to provide
write access to client PCs attached to DESQview servers.

COM Ports

Most PCs will support up to four COM ports, or serial ports as they 
are also called.  Generally, PCs come equipped with two COM ports, 
often one 9-pin and one 25-pin.  If you want to add COM ports to your
system, you can buy add-on boards containing one to four COM ports
and plug them into a free slot in your PC's chassis.  

Although COM ports have standard base addresses, these values can be
modified with the COMsetup and COMserve programs.  Unlike most
communications programs, COMpanion does not use interrupts.  This
means you will not have conflicts with COMpanion ports and COM ports
you use for your mouse or other serial devices.  This also means that

COMpanion User's Guide -- Page 9

using the 16550 UART does not result in any speed improvement with
COMpanion.  Even though COM ports that use the 16550 are referred to
as high speed, the actual bit transfer rate used on standard PC COM
ports is the same for all 8250-compatible UARTs. 

Dedicated Servers

Running the COMserve program directly from DOS makes that PC into a
dedicated server.  The PC is then a slave to the commands it receives
from the COM port selected.  COMpanion supports reading, writing and
printer sharing on dedicated servers without restrictions.  COMpanion
can be used without additional software in the following 
configurations of dedicated servers.
      laptop to dedicated server
      desktop to dedicated server
      desktop to multiple dedicated servers

Applications using dedicated servers include:
      transfer files with server
      access data base on server
      keep commonly used files on server
      run applications on server
      use printer on server
      backup files from servers on multiple PCs

DESQview Multitasking Servers

By running DESQview multitasking software, COMserve tasks can be run
simultaneously on COM1 through COM4.  This allows up to four PCs to
read files and share printers on the DESQview server PC.  You can
also run other tasks simultaneously with COMserve tasks.  See the
Technical Notes on DESQview for details on COMpanion installation
under DESQview.

Writing to a drive on a server PC running DESQview requires Stacker 
compressed drives on the server PC.  On the client PC, use the 
COMgrab command to grab a Stacker drive on the server for exclusive
write access.  The COMfree command is used to free a grabbed Stacker
drive for write access by other PCs.  COMgrab works only on Stacker
drives.

Printer contention is handled by COMserve tasks under DESQview.  Do
not use the DESQview printer contention option if you plan to print
with COMserve.  While one server is printing, the other servers will
return a busy signal if printing is attempted.  A printer is 
relinquished by a server after 16 seconds of inactivity.  

Note that a local DESQview user will not be stopped from using the 
printer, even while other PCs are printing.  To avoid conflicts, use
the PRTLOCK program to lock the printer for use from the DESQview 
system only.  The printer remains locked until the PRTFREE program is
run.

COMpanion User's Guide -- Page 10

Spooling of print data is not handled on the PC running COMserve.  
Use a program such as the DOS PRINT command to spool print data.  
Select LPT3 to access the remote printer.  The DOS PRINT command will
allow you to continue to work while it prints, or waits to print, on
the remote printer.

Limited Bi-directional Link

A bi-directional link connects two PCs with one cable and allows 
either PC to access drives on the other one.  This configuration 
requires COMserve running on both PCs under DESQview.  This 
configuration will function properly as long as both users don't try
to access a disk or printer on the other PC at the same time.  If a 
simultaneous data transfer does occur, both PCs will get errors.  One
user at a time can then restart the failed operation.  

Using Switch Boxes 

Switch boxes offer an alternative to adding physical COM ports to 
your PC to support multiple serial devices.  For example, your PC may
have one COM port, COM1, which you use for an external modem.  To
also access a remote drive through COM1, you could use a two-way
switch box.  Selecting switch A would open the line to the modem,
selecting switch B would open the line to the remote drive.  As long
as you don't need to access a file on the remote drive at the same
time as using the modem, you could manually switch between these two
external devices.

To set up the switch box, attach a cable between COM1 and the input 
of the switch box.  Then plug in the modem on the A port and the EBD
null modem  connector on the B port.  Unfortunately, there will 
probably be a little more to the setup than this since most switch 
boxes have female plugs.  Map out the hardware you will need before
the trip to the store.  

For the example above, assuming you plan to connect a 25-pin COM port
to a 25-pin switch box, you would need one two-way switch box; one
straight through 25-line cable, with female-to-male connectors; and,
if the switch box has female plugs, two DB-25 gender changers,
male-to-male.

Also note that 9-pin connectors on switch boxes are compatible with 
COMpanion, but may not be compatible with other 25-pin devices.

Some Things to Keep in Mind

 Use of DOS versions 2 and 3 limits the size of remote disks that
can be supported.  If you want to use the standard DOS commands, you 
can boot up from a floppy with DOS version 4+.  Also, you can use 
Stacker to create a drive as large as 32 Mbytes that can be accessed 
from DOS version 2 (see the Technical Notes on Stacker).

COMpanion User's Guide -- Page 11

 Use of DR DOS through release 6 imposes the disk size restrictions 
of using DOS version 3.  Also, the DR DOS PRINT command will not work
with the COMpanion remote printer driver.  You can use the COPY
command instead, but this does not provide background printing.

 DOS commands can not be used to access network disks such as 
Novell.  

 A server PC that supports more than one client PC requires the 
multitasking program DESQview and the disk compression program 
Stacker.  You can also use DESQview to allow you to run other tasks 
simultaneously with COMserve tasks.

 Simultaneous data transfer between two PCs running the COMpanion
server is not supported.  See Limited Bi-directional Link above.


COMpanion User's Guide -- Page 12

CHAPTER 3:  Installation

Installation requirements will vary with the function of PCs in your 
network.  A PC to be used as a client requires the device driver file
COMDEV.SYS be loaded in CONFIG.SYS, but a PC to be used only as 
server does not.  In most cases, it is desirable to go ahead and
install the COMpanion devices on all PCs in the network so that they 
may function as a client as well as server.

Unless stated otherwise, the following installation instructions
apply to both hard disk and floppy-based systems.  

Characters you are expected to enter are identified in bold 
typeface.  Statements entered from the command line must be
terminated by pressing the ENTER (or RETURN) key.

Using the COMpanion INSTALL Program

It is recommended that you use the INSTALL program on the COMpanion
distribution floppy to install COMpanion on your PC. The installation
sections incuded in the COMpanion INSTALL program are identified by
(INSTALL).

Insert the COMpanion floppy in a drive and enter the floppy drive 
letter followed by the INSTALL command, such as A:INSTALL.  INSTALL
will lead you through the software installation process step by
step.  You will then need to refer to the section Setting up Drive 
and COM Port Mappings and the following installation instructions.

If you are using DOS version 2, you must first change to the drive 
that contains the COMpanion floppy and then run INSTALL.

Copying COMpanion Files to your System Disk (INSTALL)

Create a directory on the drive of your choice and change to it.  On
a floppy-based system where you install device drivers, you create
the directory on the boot disk.  We like the directory name CDPN for 
COMpanion DOS Personal Network.  We assume in this User's Guide that
you create CDPN from the root directory of the C: drive.

     C:\>MD CDPN
     C:\>CD CDPN

Copy the files from the COMpanion floppy disk to the new directory.  
We assume the floppy is in drive A:.

     C:\CDPN>COPY A:*.*

On a floppy-based system, you may want to save space by deleting the
COMpanion files you will not use.

COMpanion User's Guide -- Page 13

Updating CONFIG.SYS with the COMDEV Device Driver (INSTALL)

You can skip this step for a PC to be used only as a server.  

To make the COMpanion disk and remote printer drivers available, you
will need to edit the CONFIG.SYS file in the root directory of your 
boot drive.  On a floppy-based system, this applies to boot disks. It
may be helpful to consult your DOS manual if you are unfamiliar with
the DEVICE statement.  The general form of the COMpanion DEVICE
statement follows.  Note that you must enter all values on one line.

     DEVICE = d:path\COMDEV.SYS   drive-count  N 
                  
d:path\ is the drive and directory of COMDEV.SYS.

drive-count is used optionally to allocate 1 to 4 drive letters as 
remote drives.  If not specified, one drive is allocated.

N suppresses loading of the remote printer driver.  If not specified,
the LPT3 remote printer driver will be loaded.

The following DEVICE line will allocate one remote drive and load the
remote printer driver as LPT3.

     DEVICE=C:\CDPN\COMDEV.SYS

Specify N on the DEVICE line to suppress loading the remote printer 
driver.  This option has no effect on memory requirements. 

Specify a number from 1 to 4 on the DEVICE line to allocate that many
remote drives.  Avoid allocation of drives you will never use since
searching non-existent drives can take up to four seconds for each
drive.  This option has no effect on memory requirements.  The
following device line allocates two remote drives and suppresses 
loading the printer driver.

     DEVICE=C:\CDPN\COMDEV.SYS   2   N

You must reboot your system for the COMpanion drivers to be 
installed.

Updating Your AUTOEXEC.BAT File (INSTALL)

If you want to access the executable files in CDPN from any 
directory, you will need to edit the AUTOEXEC.BAT file in the root 
directory of your boot drive and add the new directory name to the
end of the current PATH statement.  

     PATH=<former list of search paths>;C:\CDPN

It may be helpful to consult your DOS manual if you are unfamiliar 
with the PATH statement.

COMpanion User's Guide -- Page 14

We highly recommend adding the line

     BREAK=ON

to your AUTOEXEC.BAT file so that you can use CTRL-BREAK or CTRL-C to
terminate DOS commands before they complete.  To abort long file
transfers, your only alternative is to reboot.  Note:  BREAK is also 
a command you can use from the DOS prompt to enable this feature.

We also recommend you include a line in your AUTOEXEC.BAT file to 
initialize the COMpanion driver from a setup file.  

     COMSETUP  C:\CDPN\INITCOM

You will need to run COMsetup to customize the COMpanion settings, 
and then save them using the file name you specify on the command 
line.  In the previous example, INITCOM is the file name, and 
C:\CDPN\ is the drive and path to the file.

Setting Up Drive and COM Port Mappings

Make sure you reboot your system to install the device drivers added
to CONFIG.SYS before you continue with this step.

Run the COMsetup program to set up drive and COM port mappings on any
PC where you have loaded COMpanion drivers.  

     COMSETUP

COMsetup will not run under DESQview.

COMsetup gives you the ability to customize:
      drive mappings from local to remote drives
      COM port mappings for each remote drive
      COM port to use for remote printing
      remote LPT number to use
      COM port base addresses
      seconds to time-out on COM port 

Once you have defined setup values to your liking, you can save them
in a setup file that can be invoked from your AUTOEXEC.BAT file each
time your PC boots up. INITCOM is the recommended file name to use.

Hardware Installation

To connect two PCs together, plug in an EBD null modem connector to a
serial port on each PC.  Then plug in each end of a phone cable to 
the phone jack on each connector.  

If you have trouble figuring out what COM port numbers match the 
plugs on the back of your PC, consult the section below on Using the 
COM Finder.

COMpanion User's Guide -- Page 15

Using the COM Finder

Use the COM Finder if you do not know which COM port numbers 
correspond to the plugs on the back of your PC.  Begin by plugging 
the COM Finder into an EBD null modem connector, then plug the 
connector into a COM port on your PC.  Enter the COMFIND command,
which displays the COMsetup information window.   Under the active
column you will see no, yes or no/x.  The no/x entry will show up for
the COM port the COM Finder is in.  If you have other PCs connected
to this one, then no/x may show up when a remote system is off.  

Enter CTRL-R from the information window to retest the link after 
starting COMserve on a remote PC, or after moving the COM Finder to a
different COM port.  COMsetup will then update the information 
displayed.

When a specified COM port is not a valid UART, an asterisk (*) will 
show up next to the number in the COM column.  Note that a UART 
associated with an internal modem is valid, even though you have no 
way to connect to it.

Verifying the COMpanion Link

Run COMserve on the PC to act as a server:

     C:\CDPN>COMSERVE COMx

Specify 1, 2, 3 or 4 for x to indicate the COM port to use for the 
COMpanion link.

Run COMsetup on the client PC:

     C:\CDPN>COMSETUP

The active column should read "yes" if the COMpanion link is active.

If you run the server under DESQview, you may not get "yes" in the 
active column even when the link is active.  Remedy this by doing 
validity checking before you start DESQview.

If the link is not active when you expect it to be,  make sure the
COM port settings selected in COMsetup are correct.  Also make sure
the COMserve program was started on the correct COM port.  You can 
enter CTRL-R from the COMsetup information window to retest the COM
ports and update the information displayed.

If you use an adapter in your COM port and plug the EBD null modem 
connector into it, the send/receive lines may be swapped.  These 
lines may also be swapped if you have an intermediate cable, such as 
when connecting to a switch box.  Use the  as described below to 
attempt to remedy this problem, then verify the link once again. 

COMpanion User's Guide -- Page 16

Using the Flipping Cable

Use of a switch box or COM port adapters are the two most likely 
situations where the Flipping Cable might be needed.  When two PCs 
are connected directly by the connectors and cable supplied with 
COMpanion, it is extremely unlikely that the Flipping Cable will be 
needed.

There is a slim chance that the connectors or phone cable supplied 
with COMpanion are faulty.  You can use any null modem connection 
between PCs that you already know works to check for this 
possibility.  

Begin the installation of the Flipping Cable by removing one end of 
the phone cable from the EBD null modem connector on either PC.  
Attach this end of the cable to an input of the inline coupler
supplied in the package.  Attach the Flipping Cable to the other end 
of the inline coupler.  Plug the Flipping Cable into the EBD null 
modem connector.  You have now swapped the send/receive lines between
the two PCs if you are using EBD null modem connectors, null modem 
connectors from Traveling Software, or other plug-compatible 
connectors. 

COMpanion User's Guide -- Page 17

CHAPTER 4:    COMpanion Programs

COMserve  Server program run on PCs where disks and printers are 
          that you want to access.

COMsetup  Provides interface between user and COMpanion devices 
          on client PC, and is used to invoke special functions.

DRIVEMAP  Gives you information about each drive on your PC system,
          and can be used under DESQview to get the write onwership
          of Stacker drives.

DRVFREE   Frees a drive locked by DRVLOCK.

DRVLOCK   Under DESQview, locks selected Stacker drive for write 
          access by DESQview user only.

PRTFREE   Frees a printer lockd by PRTLOCK.

PRTLOCK   Under DESQview, locks selected printer for use by 
          DESQview user only.

Command Line Syntax and Parameters Common to COMpanion Programs

Parameters in italics should be replaced by values in their 
description.  

Upper case parameters are literals that should be entered as is.  

Parameters separated by a vertical line, as in VBIOS | RESET, 
represent an array of choices.  Unless stated otherwise, only one 
value can be selected for a given choice.


COMserve
---------------------------------------------------------------------

COMserve is the COMpanion server program run on PCs where disks and
printers are that you want to access.

     COMSERVE  COMx | COMx=hex-value

COMx      COM port number 1 to 4; if not specified, COM1 is used

hex-value four-digit hex value representing COM port base address;
          if not specified, the standard DOS address is used

Include COMx on the command line to run COMserve on COM ports other
than COM1, or to specify a base address that is non-standard. 

     COMSERVE COM1=06E0

runs COMserve on COM1, using base address 06E0 hex.

COMpanion User's Guide -- Page 18

After you start COMserve, the COM port used is displayed.  When you 
run COMserve from DOS, a built-in screen saver scrolls the screen up 
and down every three seconds.

As you access data on the server, the current drive, function and 
transfer rates are updated.  Transfer rate is only updated if the 
transfer takes at least half a second.


COMsetup
---------------------------------------------------------------------

COMsetup provides the interface between the user and the COMpanion
device drivers.  Use COMsetup without command line parameters to view
the current COMpanion drive settings, to change drive and COM port
settings, to change remote printer settings, or to save a setup file
containing the current settings.

COMsetup is also used to invoke special functions, such as GRAB and 
FREE for gaining write access to remote Stacker drives on a server PC
running DESQview.  Batch files are included that will invoke COMsetup
for you when you enter these special commands.

Use COMsetup in conjunction with the COM Finder to determine the COM
port numbers on your PC (see Using the COM Finder in Chapter 3).

Command Line Options

Through command line options, COMsetup provides a means to change the
COMpanion settings from a previously saved setup file, as well as to
invoke the special functions described below.  As a short cut to
entering the COMsetup command and a keyword, you can use a batch
program name specified in the descriptions on the following page.

     COMSETUP setup-file | special-function

setup-file     
          Change the COMpanion settings to values contained in a
          previously saved setup file. Setup files are created by
          using the SAVE command from the information window of
          COMsetup.

special-function    
          May be one of the special functions described below. Batch
          programs are supplied with the COMpanion software to invoke
          each of these functions. 

COMFIND   Brings up the information window and shows the status of
          COM ports in the active column. See the section Using the
          COM Finder in Chapter 3. The batch program name is COMFIND.

DOSERR    Display on standard output a table showing DOS error 
          messages and corresponding meaning for COMpanion drives. 
          The batch program name is COMERR.

COMpanion User's Guide -- Page 19

FREE d    Free the remote Stacker drive mapped to drive d that was
          previously grabbed for write access with COMGRAB.  The batch
          program name is COMFREE.

GRAB d    Grab the remote Stacker drive mapped to drive d for write
          access.  The batch program name is COMGRAB.

INFO      Display on standard output the information window.  
          The batch program name is COMINFO.

RESET d   Reset the COMpanion drive specified by d.  This forces DOS
          to update its internal drive table.  If you do not specify a
          drive, all COMpanion drives are reset.  COM ports will be
          reset only if no drive is specified.  The batch program name
          is COMRESET.

VBIOS     Force COMsetup to use BIOS video calls rather than write
          directly to the screen.  BIOS video calls provide a high
          degree of compatibility with  nonstandard systems, but are
          slower than writing directly to the screen.  The batch
          program name is COMSETV.

Information Window 

When COMsetup is run without command line options, the information
window is displayed on the screen as shown in Figure C.  If you like,
you may use the arrow keys to reposition the window.  The information
window options are displayed along the bottom of the information
window.


COMsetup V1.2 (c) Copyright 1994 Oxford House Software

     DRIVE MAPPING     STATUS OF COMDEV DRIVES
     -------------     -------------------------
     local  remote     active COM type    access
       e  --> c         no     1  ???      none




   ESC exit  F1 drive  F2 LPT3   F3 COM  F4 save


     Figure C:  Information Window


The VBIOS and INSTALL command line options also cause the 
information window to be displayed on the screen.

COMpanion User's Guide -- Page 20

Drive Mapping

From one to four local drives point to the drive letter selected on
the remote system.  The number of drives allocated can be set on the 
COMpanion DEVICE line in your CONFIG.SYS file.  See Device Driver 
Installation in Chapter 3 for more details.

Status of COMDEV Drives

The current status of each drive is indicated in the active, COM,
type and access columns.  

The active column has one of the following values:

no   COMserve does not respond on the remote PC.  This usually 
     indicates the COMpanion link is not active.  However, when
     COMserve is running under DESQview, the time constraints on a
     response may cause "no" to be reported when the link is working. 
     Use CTRL-R to retest the link if you are unsure  about the
     connection.

no/x This is a special indication that feedback characters are being 
     read on the link, but not the values expected from COMserve.
     This will occur when the COM Finder is plugged into the indicated
     COM port.  Feedback also occurs on some PCs when their power is
     turned off.  

yes  The COMpanion link is active.  

The COM column contains the COM port assigned to each drive mapping. 
COM ports 1 to 4 are supported.  When a COM port selected is not a
valid 8250-compatible UART, an asterisk (*) is displayed next to the
COM port.  

The type column indicates the type of drive mapped to on the server 
PC.  Use the program DRIVEMAP to view drive information on the server
PC.  Drive type may be any of the following:

???       Drive type has not yet been determined.

invalid   Drive is not a valid drive for use with COMpanion.

too big   Drive is too big to be used by the version of DOS running
          on this PC.

floppy    Drive is a physical floppy disk.

fixed     Drive is a fixed disk (physical, RAM, etc.).

Stacker   Drive is a Stacker compressed disk.

SUBST     Drive is defined with the SUBST command, so even if it is
          pointing to a Stacker disk, COMgrab will not work on it.

COMpanion User's Guide -- Page 21

network   Drive is a network drive, and not accessible with 
          COMpanion.

remov     Drive is a removable disk.

The access column indicates the type of access allowed on this drive.

none      Drive can not be accessed.

read      Drive can only be read from.

write     Drive can be read from and written to.

Information Window Options

The information window options appear along the bottom of the 
COMsetup information window, except CTRL-R.  Use the arrow keys to
move the information window about the screen.  

Within the option submenus, use the arrow keys or TAB key to navigate
among the choices, and use ESC to return to the information window.

ESC  Exit from COMsetup.

F1   Invoke the Change Drive Setup menu (Figure D).  For each local 
     drive you may select the remote drive to map to and the COM port
     to use.  Remote drives can be a letter from a to z.  COM ports
     may be a value from 1 to 4.  Changing a value causes the
     associated drive to be reset.  


          Change Drive Setup

          LOCAL DRIVE     e  f  g  h
          --------------------------
          remote drive    c  c  c  c
          COM port        1  1  1  1


     Figure D:  F1 - Drive Option


     Initial values:  remote drive c and COM port COM1 for all 
     drives.

F2   Invoke the Change Remote Printer Settings menu (Figure E).  LPT3
     is used for COMpanion remote printing.  You may select which COM
     port to send remote printing to, and which LPT number to use on
     the remote system.  The COM port to use for remote printing may
     be a value from 1 to 4, and the remote printer to use may be a
     value from 1 to 3.

COMpanion User's Guide -- Page 22
        
       Change Remote Printer
          Settings for LPT3

    Do remote printing on COM1
    Remote printer to use is LPT1


     Figure E:  F2 - LPT3 Option


     When the remote printer driver is not loaded, because the N
     option on the COMpanion DEVICE line was specified, the message
     "Remote printer device not loaded" is displayed.  You can not
     change remote printer values in this case.

     The COM port used for remote printer may also be shared by 
     remote drives.  Background printing, such as with the DOS PRINT 
     command, will not interfere with drive accesses on the same COM
     port.

     Initial values:  COM1 and LPT1.

F3   Invoke the Change COM Port Setup menu (Figure F).  For each of
     COM1 to COM4, you may select the base address to use. This may
     be helpful if you want to use an add-on board containing COM
     ports that are not at the standard addresses. An asterisk (*)
     appears next to base addresses that do not represent a valid
     8250-compatible UART.  The base address must be entered as four
     hex digits.

     COM time-out controls the number of seconds to wait for a
     response from the remote system before a time-out error is
     generated.  Values of 1 to 9 correspond to 1 to 9 seconds.  A
     value of 0 indicates a time-out of 16 seconds.  Some uses of
     DESQview may require the use of 0 (see the Technical Notes on
     DESQview).  In most cases, this value will not need to be
     changed.

     Initial values:  COM1 is 03F8, COM2 is 02F8, COM3 is 03E8 and
     COM4 is 02E8; and COM time-out is 6 seconds (Figure F).


    Change COM Port Setup

    COM 1  base address  03F8
    COM 2  base address  02F8
    COM 3  base address  03E8
    COM 4  base address  02E8

    COM time-out is 6 seconds


     Figure F:  F3 - COM Option

COMpanion User's Guide -- Page 23

F4   Invoke Save Setup menu.  Save the current COMpanion settings to
     a disk file. This file may then be used to change the COMpanion
     settings as described below in Using a Setup File.  Enter a
     valid drive, path and file name in which  to save the current
     setup values.  The current drive and directory are used if you
     enter only a file name.

     If the file you specify already exists, you are given the option
     to overwrite it.  If an error occurs, no file is created.

CTRL-R   
     CTRL-R will retest COM ports for the presence of a COMpanion
     server and update the information displayed.

Using Setup Files

Use setup files to automatically change the COMpanion driver 
settings.  Setup files are created with the F4 option from the 
COMsetup information window, as described above.  To install the 
settings from a setup file, enter a setup file name on the COMsetup 
command line.

     C:\>COMSETUP setup-file

Here, setup-file refers to the drive and path of a setup file name
you previously saved.  All drives are reset by this command, and COM 
ports are re-initialized.

To initialize the COMpanion settings each time you boot up your PC, 
add the COMsetup command line above to your AUTOEXEC.BAT file.  
INITCOM is the recommended name and is what the INSTALL program uses.


DRIVEMAP
---------------------------------------------------------------------

Use DRIVEMAP to get information about the drives on your PC.  When
run under DESQview, DRIVEMAP indicates the write ownership of Stacker
drives, reflecting COMgrab and DRVLOCK commands that have been
issued.

DRIVEMAP reports on the use of ASSIGN, JOIN and SUBST drive 
commands.  Please refer to a DOS manual for a description of these 
commands.  SUBST drives provide an alternate drive letter to 
reference a drive and path.  SUBST drives on the server PC can not be
used with the COMgrab command from a client PC.  If the ASSIGN 
command is used, whether an assignment exists or not, all drives on 
the server PC will be read-only when running under DESQview.  JOIN 
drives do not affect the operation of COMpanion.

When a system error occurs and locks up the server PC running 
DESQview, any Stacker drives that were grabbed for writing with the 
COMgrab command will be read only after rebooting the PC.  After you
run DRIVEMAP, all Stacker drives will be reset to their writable 
state.

COMpanion User's Guide -- Page 24

DRVFREE
---------------------------------------------------------------------

Use DRVFREE to release a Stacker drive that was locked with the 
DRVLOCK command.  Specify the local drive letter to free on the 
command line.


DRVLOCK
---------------------------------------------------------------------

Use DRVLOCK under DESQview to lock a Stacker drive for exclusive 
write access from the DESQview server PC.  This will disable the use 
of COMgrab by any PCs attached to the server.  Specify the local 
drive letter to lock on the command line.  Use the DRVFREE command to
allow other PCs to grab the drive for writing.

Run DRIVEMAP to view the status of drives on the server.


PRTFREE
---------------------------------------------------------------------

Use PRTFREE to free a printer that was locked with the PRTLOCK 
command.  Specify the printer to free on the command line (LPT1, LPT2
or LPT3).


PRTLOCK
---------------------------------------------------------------------

Use PRTLOCK under DESQview to lock a printer for exclusive use on 
the  DESQview server PC.  This will disable the use of the specified 
printer by any PCs attached to the server.  Specify the printer to
lock on the command line (LPT1, LPT2 or LPT3).  Use the PRTFREE 
command when finished printing to allow other PCs to use the printer.

COMpanion User's Guide -- Page 25

CHAPTER 5:   Technical Notes

DESQview
---------------------------------------------------------------------

Installation of COMpanion Files

From the DESQview main menu, select Open Window, then select the Add
a Program function.  From the Add a Program window select Other (Add
Program Not in List).  Enter the path to COMpanion files, C:\CDPN, or
the installation directory you chose.  COMpanion files are predefined
with key codes as shown below:

     COMserve COM1  C1
     COMserve COM2  C2
     COMserve COM3  C3
     COMserve COM4  C4

The COMserve programs are set to use a 24K window, and 16K of system
memory.  The directory used to find the program is C:\CDPN.  In order
to change these settings, you will have to use the Change a Program
selection from the DESQview Open Window menu.

The value of system memory is checked by COMserve for at least 16K,
32K or 64K for the allocation of a buffer for writing to disk.  You 
will notice a slight improvement in disk write time if you use 32K or
64K.  If you specify less than 16K, no write buffer is allocated, and
write time may take up to twice as long.

General Concept

DESQview allows you to run one to four COMserve tasks in the 
background, and lets you do other work on your PC at the same time.  
After following the installation procedure above, you start COMserve 
tasks on the COM ports where other PCs are connected.  DESQview will
cycle through the COMserve tasks to give approximately equal time to
each one.  

If you will be running other applications on the DESQview server, 
then you may want to adjust the amount of time allocated to the 
COMserve tasks.  Select Rearrange from the DESQview main menu, and
then select Tune Performance.  DESQview defaults for Foreground and
Background ticks are 9 and 3.  This gives the application you run
triple the time of background tasks.  Although this may sound good,
selecting a higher value for COMserve tasks can work quite well for
both your DESQview application and the client PCs accessing your
disks.  Swapping these values so that Foreground ticks is 3 and
Background ticks is 9, will allow COMserve to run nearly as fast as
possible.  If performance in your DESQview application is inadequate,
move the values closer to even and try again. 

COMpanion User's Guide -- Page 26

Adjusting Time-out Value on Client PC

If you get "drive not ready" error messages accessing valid drives on
a DESQview server, you may need to adjust the time-out value used by
the COMpanion drivers.  In most cases you will never need to change
the COM time-out value from 6 seconds.  

From the COMsetup menu, select COM (F3) to access the time-out 
value.  A setting of 0 sets time-out to 16 seconds.  Since DOS
retries after an error occurs, a time-out of 16 seconds can cause a 
delay of 32 seconds before you get an error message accessing remote 
drives.

Printing

COMserve recognizes when it is running under DESQview and will allow
only one of the active COMserve tasks to print to the same printer at
a time.  After 16 seconds of inactivity, another COMserve task may
begin printing.  If you use a print spooler on a client PC, such as
the DOS PRINT command, then the spooler will keep trying to print
until the printer becomes available.  

DESQview offers an option to manage printer contention.  This option 
should be set to N(o) in the Performance option of the Advanced 
DESQview Setup to let COMserve provide printer support.

Use the PRTLOCK command to let a local DESQview user print without 
interference from PCs attached to the server.  When finished 
printing, enter a PRTFREE command to free the printer for use by 
other PCs.

Screen Blanking

The DESQview screen blanker will allow tasks to continue to run even 
though the screen is blanked.  Please use it!


DOS and DR DOS
---------------------------------------------------------------------

DOS Versions 2 and 3

The disk size supported under DOS version 2 is limited to 4086 
clusters.  A cluster contains some number of sectors, which are the 
smallest units addressable on a disk drive.  Sector size is usually 
512 bytes.  On XT systems, drives were often defined with 8 sectors
per cluster, or 4096 bytes.  If you multiply times 4086 clusters, you
find a 16 Mbyte disk can be supported.  See the Technical Notes on 
Stacker for creating 32 Mbyte drives on a server that can be accessed
from a DOS 2 client.

COMpanion User's Guide -- Page 27

On AT systems, 4 sectors per cluster is common.  Smaller clusters are
desirable for small files since each file requires at least one
cluster.  With DOS 3.0, the maximum cluster count was raised to 
16,384.  Yet the 16-bit value used to represent sector numbers on the
disk still limits disk size to 32 Mbytes under DOS 3.

DR DOS

DR DOS versions 3 through 6 support the functions of DOS 3.3.  In 
addition, large disk drives are supported in the same fashion as for 
DOS 4+.  Unfortunately, the external interface for large disk drives
is not supported, so you will have the same 32 Mbyte disk size 
restriction for COMpanion remote drives as users of DOS 3 on a client
PC.

When you run COMserve under DR DOS, your disks that are greater than
32 Mbytes will be accessible to client PCs if they are  running DOS
4+.

The DR DOS PRINT command does not support the use of the COMpanion
remote printer driver.  You can use the DR DOS COPY command to send a
file to the COMpanion remote printer as follows:

     COPY filename   LPT3

Unlike the PRINT command, you must wait for COPY to finish printing
before you can resume other work.

The DR DOS SCRIPT command works properly with the COMpanion remote
printer driver.  To format a text file for output to a remote 
PostScript  printer, enter:

     SCRIPT   filename   LPT3 

As with the COPY command, you must wait for SCRIPT to finish printing
before you can resume other work.


Early Bit Detection (EBD) Null Modem Connectors
---------------------------------------------------------------------

The connectors supplied with the COMpanion package are very nearly
null modem connectors.  The only difference is an additional jumper
from the Receive Data  (RD) line to the Ring Indicator (RI) line. The
information gained from using the Ring Indicator allows COMpanion to
function at the full speed of the UART without the use of
interrupts.  

The term Early Bit Detection (EBD) refers to the ability of COMpanion
to recognize the arrival of data on the Ring Indicator before a byte
is fully serialized by the UART.  

COMpanion User's Guide -- Page 28

The physical wiring of EBD connectors matches that used by connectors
from Traveling Software, so you could use a connector from Traveling
Software on one PC and connect it to a COMpanion EBD connector on
another PC.  The resulting data transfer rate would be three-fourths
full speed since the Traveling Software connectors do not have the
EBD feature.  If you use non-EBD connectors between two PCs, the data
transfer rate is one-half full speed.

If you are making your own EBD connectors, you will need to connect 
the yellow, green, red and black phone wires as follows:

yellow    Transmit Data (TD)
green     Signal Ground (SG)
red       Signal Ground (SG)
black     Receive Data (RD) and Ring Indicator (RI)

The actual pin numbers on the connector will vary according to 
whether a 9-pin (DB-9) or 25-pin (DB-25) connector is used.  The 
following table shows the assignments for female connectors:

Signal                   DB-25     DB-9
------                   -----     ----
Transmit Data (TD)       2         3
Receive Data (RD)        3         2
Signal Ground (SG)       7         5
Ring Indicator (RI)      22        9


Miscellaneous
---------------------------------------------------------------------

Screen Blankers

Most screen blankers will deactivate the running programs.  This 
means that if you start COMserve and a screen blanker comes along, 
requests from the client PC will not be serviced.  COMserve has a 
built-in screen saver that scrolls the screen up and down every three
seconds, so it is recommended that screen blankers be disabled while 
COMserve is running.  One exception is the DESQview screen blanker, 
which does allow tasks to continue running while the screen is 
blanked.

COMpanion Drives Under Windows

It is best to be sure that remote COMpanion drives you will access 
under Windows are active before you start Windows.  You can run 
COMsetup under Windows, but you must close (Exit) the DOS window 
after you finish to avoid conflicts with COM ports in Windows 
applications.

Memory Optimizers

The memory optimizers MEMMAKER and QEMM will not work with COMpanion.
Please bypass the COMpanion device driver COMDEV.SYS when running
these optimizers.

COMpanion User's Guide -- Page 29

Mouse Port Conflict under Windows

If you run COMserve in a DOS window under Windows, and accidentally
select the same COM port the mouse is in, the mouse under Windows
will go crazy. You must then exit from Windows.

Laptops

If you use a laptop with power saving features, you may get "Drive 
not ready" messages from the loss of power when these modes are 
activated. To avoid this problem, use an AC adapter, or temporarily 
disable the power saving features.

Minimum Configuration COMpanion Programs

If you use the COMpanion INSTALL program, the installation directory
will contain a subdirectory called MINICOM that contains minimum
configuration versions of COMDEV.SYS and COMSERVE.COM. These can be
mixed with the full versions. Reference these versions of the
COMpanion programs if you need to conserve memory resources on your
PC. This version of COMDEV.SYS requires only 4.5k of memory, and
COMSERVE.COM only 12k. Data compression is not performed, and the
COMgrab function is not supported. 


Performance
---------------------------------------------------------------------

Disk Caching Programs

If you use SMARTDrv, or other disk caching programs on your PC, you
should be aware of their affect on COMpanion drives.  SMARTDrv can
make accessing data on a COMpanion drive very quick after the first
time it is read.  The price you pay for this will vary with your 
system type, but transfers are roughly 10% slower when using 
SMARTDrv.  Write caching is not recommended.  If you attempt to write
to a read-only drive with write caching enabled, you will have to
re-boot your system.

SMARTDrv affects the performance on the server PC as well.  It is 
recommended that you disable caching on drives to be accessed on a 
server PC.

Disk Compression Programs

If you use a disk compression program, such as Stacker, DOUBLE DISK 
or SuperStor, your operating system must compress or decompress data
every time it is accessed on your disk.  The time required by the
disk compression program is reflected in the transfer rate displayed
by COMserve.  

COMpanion User's Guide -- Page 30

Time Lags Caused by Inactive Remote Drives

Programs that check for the presence of drives, such as File Manager 
under Windows, will cause the system to wait two to four seconds per
remote drive that is inactive.  If you need to keep a drive mapping
available for a drive that is not always available, you can map it to
a drive that is active to avoid the delay until such time that you
need it.

Another way to deal with drives you won't access too often is to 
define only as many COMpanion drives as you will actively use, then 
remap one of them to another drive as you need it.  


Stacker
---------------------------------------------------------------------

Stacker is a software package from Stac Electronics that doubles your
disk capacity using data compression.  Stacker software is required 
to provide write access to drives on a server PC running DESQview.  
Use Stacker to create and manage drives on your PCs.  You have the 
ability to shrink and grow Stacker drives, and create new ones from 
uncompressed disk space.  

One application of Stacker is to create a drive on the server PC for 
each client PC on your network.  This would provide a writable drive 
on the server for each PC on the network.  Other Stacker drives on 
the server would then be accessible for writing on a first come first
serve basis using the COMgrab or DRVLOCK commands.

Restriction on Loading Stacker Device Driver in Low Memory for 
Stacker through version 3.1

The Stacker device driver provides a means to be loaded into high 
memory.  In order for COMpanion to work under DESQview, you must load
the Stacker device driver in low memory.  In versions of Stacker 
prior to 3.1, do not use DEVICEHIGH to load Stacker, or a similar 
command for a memory manager other than HIMEM.  In Stacker 3.1, do
not use the STACHIGH device driver.

You can still use the EMS option to allow Stacker to use EMS memory 
for its built-in cache.

Creating a 32 Mbyte Disk Drive Accessible from DOS 2

To create a 32 Mbyte Stacker disk that you can access from a DOS 2 
client, enter one of the Stacker command lines from the DOS prompt.  
These commands will create a drive of fewer than 4086 clusters, but 
nearly 32 Mbytes in size.

COMpanion User's Guide -- Page 31

Stacker 2.0 command line

     SCREATE   d:  /S=16   /R=2.0   /C=8

Stacker 3.x command line

     CREATE   d:   /S=16M   /R=2.0   /C=8

d: specifies the drive letter to be used to host the Stacker drive.  

/S=16 or /S=16M will use16 Mbytes physical space on drive d:.  

/R=2.0 specifies a compression ratio of 2:1.  This is the default
value.

/C=8 specifies 8K bytes per cluster.  This is the default value.

If you expect compression of greater than 2:1, then you may adjust 
the /S and /R values so that S times R is 32 or less.  Please check 
your Stacker User's Guide for more details on these commands.

