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ANSIPLUS and Multitaskers or Task Switchers


The ANSIPLUS INSTALL program can recognize and alter the OS/2 CONFIG.sys file just as it can for MS-DOS. Once ANSIPLUS is installed, it will be available to all OS/2 full screen and windowed DOS sessions. ANSIPLUS features will not be available to OS/2 sessions, however, because ANSIPLUS is currently a DOS, not an OS/2 device driver. Only a few other issues affect ANSIPLUS under OS/2:


Because of DESQview’s handling of drivers loaded before it starts, and because it takes over an interrupt vector used by ANSI drivers, DESQview presents a challenge for an attached console driver like ANSIPLUS:

Because of these problems, to use the ANSIPLUS console driver in a DESQview window, it must be loaded as a TSR after the window has started. The best way to do this is to create a batch file that loads ANSIPLUS and does anything else needed to set up the window, and then executes the command associated with the window.

And there are a few more complications:

The Freeware ANSIPLUS.exe device driver satisfies all these requirements. The old Shareware ANSIPLUS.sys driver, however, cannot be loaded as a TSR except by another program, such as Quarterdeck’s And because loading the CON device driver ANSIPLUS.sys will change the system console, does not appear to completely install the driver, at least as far as, the MS-DOS command shell, is concerned. This must be corrected by entering a CTTY CON command in each window after ANSIPLUS.sys has been loaded.

The ANSIPLUS driver is DESQview aware: after it is loaded in a DESQview window, it uses alternative video buffers for video output if the screen is not "virtualized", calls the BIOS for cursor positioning instead of writing directly to the video controller, releases time slices when waiting for key input, disables the ANSIPLUS screen saver, and prevents the video RAM from being used to store scroll-back (EMS scroll-back is still allowed).

Task Switchers

When a task switcher, such as MS-DOS DOSSHELL, is running, the user should have independent ANSIPLUS consoles for each task. To provide this functionality, ANSIPLUS supports the Microsoft Int 2Fh functions 4B01h-4B05h task switcher interface, which is used by both DOSSHELL and Windows 3.1 Standard Mode. Via the interface, ANSIPLUS reports its instance data to the task switcher and monitors switcher activity to control allocation and destruction of EMS handles for session scroll-back, if the task switcher allows this. ANSIPLUS should also work with other task switchers that support this interface.

© Copyright 2000-2007, Kristofer Sweger. All rights reserved.
Rev. 11/01/07