Category : Utilities for DOS and Windows Machines
Archive   : CHANNEL.ZIP
Filename : MC.DOC

What is Multiple Choice ?

Multiple Choice enables you to have multiple programs in memory, and,
with a keystroke, switch which program is displayed and running.
The memory of your computer is divided into several channels, each
like a separate computer with its own screen and able to run a program.











*****************************************************************************


Starting Multiple Choice

Multiple Choice is shipped with 3 preset channels.

Channel #1 is a small channel, with 24K, enough space to format or
copy a diskette, or to use the on-line help facility, etc.
Channel #2 is 55K, which is big enough for a small application
like WordStar.
Channel #3 owns the remainder, which will vary with the amount of
memory in your computer. In a 256K computer, this will be
about 120K, enough for a fairly large application like 1-2-3.

To start Multiple Choice simply type "MC" at the DOS prompt. Multiple
Choice will start the channels, switching screens and displaying a
header on each. After MC starts the last channel, it transfers control
to Channel #1.








You can now run three programs, one on each channel. Only one channel's
screen is displayed, but you can easily switch to another. When
you do, the old program and its screen are "frozen" and
stored until you return to it. The new channel's program and
screen are brought in and activated so that you can use it normally.

To switch channels, press and a keypad number. For example,
to switch to channel #2, hold down and press on
the numeric keypad located on the right side of the keyboard.

While is down, you can also press to display
a status line that will tell you what channel you are on, and how
much memory that channel owns. The status line will be displayed
while both keys are depressed.







On-Line Help
We suggest that while you first use MC, you use Channel #1
to display this HELP file by typing MCHELP. At any time,
you can switch to another channel and run a real application,
and switch back to the HELP channel if you need it.

Snapshot
MC includes a full-screen snapshot feature that you can
activate by holding down and pressing .
Whatever appears on the screen will be
saved in a file called "SNAPSHOT.TXT" in your current
directory. You can then use this file from another
channel, such as reading spreadsheet data into your
word processor.

Exit
If you want to exit MC and return to regular (boring) DOS,
press WHILE you are holding down ,
displaying the status line. MC will terminate when you
release all three keys.
Be careful not to have any application programs running
on other channels, though; they will all be terminated.


*********************************************************************


Graphics

Using MC as above, you can run programs which use graphics provided
they leave graphics mode before you do a channel switch. If you want
to switch out of a program while it is displaying graphics, you must
reconfigure MC to expect that by specifying the "G" option when you
set channel sizes as described below.

After doing the reconfiguration and invoking your new version of MC,
only one channel may be in graphics mode at a time, but you can switch
in and out anytime.

NOTE: Some software products which use unconventional programming
practices may not switch properly when they are displaying graphics.
This will not damage any data, but when returning to the application,
the screen may not be readable until the application returns to a
non-graphic mode.




*************************************************************




Setting channel sizes

You cannot set channel sizes while you are running MC. If MC
is running, you should exit using the command described
above. You then have two options for changing the channel sizes in
MC. You can invoke MC with new channel sizes to run immediately, or
you can change the "preset" channel sizes which MC uses when no
command line is present. In either case specify a list of memory
sizes (in kilobytes) separated by spaces. If any size number is
less than the minimum, 24K, it will automatically be set to the minimum.
If there is at least 30K of leftover memory, MC will make another channel.
Otherwise the extra memory will be added to the last channel.







e.g. To: set two channels immediately, one of minimum
size (24K), and one with the rest of memory

Type: MC 24 or MC 0

To: set eight channels, Channel #1 - 60K, Channel 2-7
minimum size, Channel 8 - the rest of memory
(this requires at least 320K of memory)

Type: MC 60 0 0 0 0 0 0

To: set either of the previous examples as pre-sets,
precede the numbers with a "p"

Type: MC p24 or MC p0
or
MC p60 0 0 0 0 0 0

Now you can invoke MC with these pre-sets simply by typing "MC" at the
DOS prompt.

NOTE: Setting pre-sets will modify your existing MC.COM file on the
disk. The MC.COM file must be on the default disk and directory, and
it cannot be write-protected.
******************************************************************
Channel Size Computations

Memory calculations:

Size of DOS: 27K
Size of MC: 4K + 6K * number of channels that you want

For example, you have 256K of memory

Subtract 27K for DOS, and 4K for the base size of MC
256K - 27K - 4K = 225K

If you want three channels, subtract another 18K (6K * 3)
225K - 18K = 207K

To set up one large channel, one small (minimum size) channel, and
one other channel, for example

channel 1 (large) 118K
channel 2 (minimum) 24K

207K - 118K - 24K = approx 65K left for channel #3




You need not specify the last channel. MC will automatically
assign the remaining memory to it.

So...
set pre-sets based on these calculations by typing:

MC p118 24

Then, whenever you invoke MC, just type:

MC

and three channels will be set up: 118K, 24K, and 55K approximately.
The third channel may vary slightly depending on the version and release
of DOS that you are running.






************************************************************************




NOTE (for systems that BOOT from FLOPPYS):

When MC starts, and occasionally while it is running, it will attempt
to access the file COMMAND.COM
MC will expect to find this file on the boot drive unless
the following command is executed first. (It may be placed in your AUTOEXEC.)
set comspec=
where is the path (including the name) where COMMAND.COM can be found.
For example, if you have a hard disk, C:, but your PC boots from a floppy
disk, copy COMMAND.COM to the hard disk (COPY A:COMMAND.COM C:), and set
up the following command to be executed before running MC:
set comspec=C:\COMMAND.COM
If you have a two floppy system, your applications already require you
to have COMMAND.COM on their system disks.





**********************************************************************

NOTES TO ALL USERS:

1) Floppy disks
If you are using files on a floppy disk with an application, and you
switch to another channel which requires different diskettes, there
is a danger of corrupting the data. Try to group your application
programs and data files onto sets of diskettes that will not need to
be changed while switching channels. If you must switch diskettes,
try to insure that no activity is taking place on them.
2) Control-S
Due to the nature of DOS and of MC, if you type to stop
the scroll of a DOS command (such as type), you will not be able
to switch to another screen, or to use the SNAPSHOT or EXIT features
until you resume scrolling with .
The same thing may occur with some applications when
or is used. The application program will still function,
though, and MC may be freed by doing some disk activity.
3) File Sharing
Try to avoid sharing files between application programs on different
channels. If either program writes to a file which the other reads or
writes, the data may not be updated properly.

***********************************************************************


COMMAND SUMMARY:

switch to channel specified by
display channel status
create snapshot file (SNAPSHOT.TXT)
terminate all applications and MC

INVOCATION:

mc Invoke MC with preset channels
mc Invoke MC with specified channel sizes
mc g Invoke MC with specified channel sizes and graphics
mc p Set MC preset channel sizes
mc pg Set MC preset channel sizes and graphics

where is a set of channel size numbers in kilobytes,
separated by spaces




***********************************************************************

MESSAGES:

Improper command line
- MC could not understand the command line you entered
Bad COMSPEC in environment
- the COMSPEC= string in your environment was not usable by MC.
Type "SET" from the DOS prompt to see what is in your environment.
Memory error.
- You do not have enough memory for the requested operation.
Permanent channel sizes set.
- You have successfully set your channel size pre-sets.
Could not update MC.COM.
- MC.COM was not on the default drive and directory when you
tried to set channel size pre-sets.
Catastrophic error.
- one of your channels tried to terminate itself, or
COMMAND.COM could not be found at some time.
Terminating MC.
- MC has exited, either because of a catastrophic error, or
because you invoked the exit command .


********************************************************************





Multiple Choice (c) 1985 Awesome Technology, Inc.
Multiple Choice Documentation (c) 1985 Awesome Technology, Inc.
Multiple Choice was written by Jason S. Loveman


Awesome Technology, Inc.
177 Webster St.
Suite A-416
Monterey, CA 93940
(408) 646-1384










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