Microsoft KB Archive/78966

= FastTips: Using MS-DOS Applications with Windows 3.0 Q & A =

ID: Q78966

SUMMARY
This article contains the complete text of the &quot;Using MS-DOS Applications with Windows 3.0&quot; fax script.

This fax script is available to customers who call the Microsoft FastTips Service for Operating Systems at (800) 936-4200.

MORE INFORMATION
Microsoft Windows, Version 3.0 Microsoft Automated Product Support Service Fax-Script Questions and Answers: Using MS-DOS Applications with Windows 3.0 -

1. Q. What is a PIF file?

A. Program information files (PIF) are used by Windows to run specific DOS applications correctly. For more information on PIF files, see Chapter 12, page 440, in your &quot;Microsoft Windows User's Guide&quot; for version 3.0.

2. Q. I am running Windows in 386 enhanced mode and yet I can only run one or two DOS applications at a time. Sometimes I can't even run one DOS application. How can I correct this problem so that I can use my DOS applications?

A. Windows 3.0 in 386 enhanced mode can run multiple DOS applications at the same time provided your computer has sufficient memory. Multitasking does take a lot of memory. Running just two DOS applications may use more than 1.5 megabytes (MB) of memory. To help meet this demand, Windows 3.0 running on a 386 computer can use some of the free space on the hard drive as virtual memory.

If your computer has less than 4 MB of memory, Windows may be     able to run only one or two DOS applications concurrently, even if there are several MB of free space on your hard disk.

If your computer has only 2 MB of memory and your hard drive has less than 4 MB free, then Windows may not be able to run even one DOS application. In this case, freeing up an additional 2 or     3 MB of space on your hard drive that Windows can use as virtual memory may let you run these DOS applications.

3. Q. I am trying to run a DOS application that talks to a modem or     another computer. Every time I switch back to Windows it loses the connection. What can I do?

A. If you are running Windows on a 286 computer or in standard or     real mode on a 386 computer, DOS applications cannot be run in      the background. When you switch to another program, the previous application is put on hold. Programs that require constant contact with a modem or other communications device will not run properly in real or standard mode when you switch back to     Windows or switch to another application.

If you are running Windows in 386 enhanced mode and have 4 MB or     more of memory, by making the following changes to its PIF file, you may be able to run in the background a DOS application that requires constant contact with a modem.

Note: If you are not familiar with Windows PIF files and the PIF Editor, we recommend that you review Chapter 12 of your &quot;Microsoft Windows User's Guide&quot; for version 3.0 before carrying out this procedure.

a. Using the PIF Editor, open the PIF file for your DOS application.

b. In the main PIF Editor dialog box, enable the &quot;Background&quot; option by clicking its box. An &quot;X&quot; will appear to show that this option is enabled.

c. Click &quot;Advanced&quot; to open the Advanced Options dialog box.

d. In the section labeled &quot;Multitasking Options,&quot; if        there is an X in the box for &quot;Detect Idle Time,&quot; click it to         turn it off.

e. Click OK to exit Advanced Options, then select &quot;File&quot; and &quot;Save&quot; to save these changes.

For more information on enabling your DOS applications to     multitask see pages 461 through 465 of your &quot;Microsoft Windows User's Guide&quot; for version 3.0. KBCategory: kbother kbfasttip KBSubcategory: win30 Additional reference words: 3.00 3.00a QWW30 ivrfax

Last Reviewed: November 23, 1994