June 14, 1991


                S3 PROTECTED-MODE DRIVER FOR AUTOCAD/386 r. 10


Provided on this diskette is a protected-mode driver for AutoCAD/386, r. 10
named  "S3PADI40.EXP."  This is an ADI 4.0-compliant display-list driver, which
runs exclusively in protected-mode.  Also included are files containing the
character font used by the driver, which should be copied to the default
working directory used for AutoCAD drawings.  The file ACADPROT.BAT can be used
to copy both the driver and font files, by first making the directory
containing the executable files for AutoCAD/386 the current working directory,
and then typing
                    A:ACADPROT 

The driver can be installed manually by either of the two methods described in
the "AutoCAD Installation and Performance Guide" - the simplest method is to
rename the driver "ADIDISP.EXP" and copy it to the directory where the Auto-
CAD/386 r. 10 executable file resides.  Alternatively, the driver can be
copied, without renaming, to any desired directory, as long as the environment
variable DSPADI is set to the full path name of the driver.  In the latter
case, for example, the driver could be copied to a directory
"C:\ACAD\DRIVERS", with the following command given before running AutoCAD:

        SET DSPADI=C:\ACAD\DRIVERS\S3PADI40.EXP

(If this is the preferred method, this command could be inserted into the
AUTOEXEC.BAT file, so that it is run automatically whenever the system is re-
booted.)

Note that, unlike a real-mode driver, a protected-mode driver is NOT run before
starting up AutoCAD - AutoCAD/386 will find the driver and load it.  It is
necessary, however, to configure AutoCAD/386 the first time the driver is used.
This is a two-step process.  The first step involves use of the utility
CFIG386, which is provided on both the AutoCAD/386 distribution diskettes and
the Phar Lap DOS-Extender diskettes.  The second step is to set the correct
display driver options the first time AutoCAD is used with the S3 driver.

CFIG386 is a utility which writes startup parameters into the header of a
protected-mode executable file, so that the Phar Lap DOS-Extender configures
itself appropriately as each application is run.  AutoCAD/386, as shipped from
Autodesk, is no exception, and comes pre-configured for its own default
settings.  In order to use the S3 driver, it is necessary to add one more pa-
rameter to the AutoCAD/386 header.  This is done with the following command:

        CFIG386 ACAD -CALLB 2

Note that it is necessary to run this command only once, and that this should
not affect the operation of other drivers.  The only exception to this would be
if there is another driver which requires that the same parameter (CALLB or
CALLBUFS) be set to a value higher than 2, in which case the higher value
should be used.

To perform the second step of the configuration process, it is necessary to run
AutoCAD/386 and select the correct display driver option.  This is done by
selecting the "Configure AutoCAD" option from the main menu, then selecting
"Configure video display," and finally selecting "ADI P386 display" from the
menu screens that appear.  Following completion of the configuration, AutoCAD
can be run in the normal way.

When running, the driver will automatically configure itself for the highest
resolution mode available for the particular type of monitor that is connected
to the display adapter.  In addition, the driver has two internal configuration
options, which the user can change at any time by selecting "Configure AutoCAD"
from the main menu.  These options are:

1.  To change the screen background from the default black to white, and

2.  To change the amount of display-list memory to be allocated (the default is
    2MB)

To access these options, first select "Allow detailed configuration," and then
"Configure video display."  This will result in two additional prompts to the
user.

In the case of display-list memory allocation, the user is asked to enter the
number of 16K pages to allocate.  Anything less than 5 pages (80K) will result
in display-list management being turned off, since 80K is the minimum required
to function properly.  It is recommended that as much extended memory as
possible be allocated for efficient operation (note that expanded memory - the
LIM specification - can NOT be used by the protected-mode driver).  Note that
it is not necessary to limit the allocation to the amount of physical memory
present in the system - once the limit of physical memory is reached, the
Virtual Memory Manager (which is bound into the AutoCAD executable) will begin
swapping memory to disk.  However, if this occurs, there will be a considerable
slowing of the program.  Since both AutoCAD's memory usage and the driver's
display list are allocated at runtime, it may take a small amount of trial and
error to determine the maximum number of display-list pages that can be
allocated before the Virtual Memory Manager starts swapping between memory and
disk on a given computer.  The user can change the number of display-list pages
to be allocated at any time by following the above instructions (but be aware
that when this is done, data previously in display-list memory will be lost).