Some of the Computer Conservation Society’s computer emulators are MS-DOS or PC-DOS programs written as long ago as the 1980s and 1990s. They may not run (without assistance) on current versions of Microsoft Windows. There are two problems:

• 16-bit programs are incompatible with 64-bit versions of Windows. (They may still run on 32-bit versions of Windows.)
• Some programs require “fullscreen mode” which is no longer supported.

You may get an error messages like one of these:

(Attempting to run in cmd.exe on 64-bit Windows 10)

(Attempting to run in cmd.exe on 32-bit Windows 7)

(Attempting to run as a Windows executable file in 64-bit Windows 10)

(See Microsoft knowledgebase article: https://support.microsoft.com/en-us/kb/926657 )

There is an easy way round these problems: DOSBox is a freeware DOS emulator written for running classic computer games. It works equally well for computer emulators. It appears as a window containing a DOS command line interpreter. DOSBox is well documented on the web. There are examples of its use on YouTube and a full User Manual included in the download.

Installing DOSBox for running CCS emulators

1. Create a folder to accommodate the troublesome emulator(s):
   - e.g. A folder called “DOSems” on the desktop. (Folder names are not significant, so long as they are used consistently, so you can choose a different one if you wish.)

2. Download and install DOSBox from www.dosbox.com:
   - Click on “Downloads” (just under the banner heading).
   - In the “DOSBox (specific versions)” panel, click on “Windows” to download the installer file “DOSBox0.74-win32-installer.exe”. Save it to your desktop or Downloads folder. (0.74 is the DOSBox version number at time of writing.)
   - Double-click the downloaded installer file and follow the onscreen instructions to install DOSBox.

3. Mount the folder created in step 1 as a virtual hard drive in DOSBox:
   - From the Windows Start button, find “DOSBox-0.74” in “All Apps” (or “All Programs”), click to expand it and select “DOSBox 0.74 Options” (or “Options” and then “DOSBox 0.74 Options”).

   The configuration file opens in Notepad.
   - Scroll down to the very end of the file where you’ll find:

   [autoexec]

   # Lines in this section will be run at startup.

   # You can put your MOUNT lines here.

   - Add three more lines:

   MOUNT C C:\Users\Steve\Desktop\DOSems

   KEYB UK

   C:

   Modify this example so that the first line mounts your new folder on what DOSBox regards as its “C: drive”. (If you aren't sure of the path name, right-click the folder and select ‘Properties’ so that the ‘Location’ is displayed.)

   The second line configures DOSBox for a UK keyboard. For other countries see www.dosbox.com/wiki/KEYB. (Note that KEYB is in upper case.)
   The third line changes directory from the default Z:\> to C:\>.

   - Finally, save the configuration file (File menu > Save). DOSBox is now ready to use.

• When running a computer emulator in DOSBox, clicking within the DOSBox window is usually sufficient to associate the Windows cursor but, when this happens for emulators with a graphical user interface, the cursor can become confined to the window. Release the cursor, when you wish to exit, by typing Ctrl+F10. (i.e. Press F10 while pressing Ctrl.) See, also, the note in the PegEm2 example below.
• DOSBox runs in a window with a default resolution of 640x480. This can be changed:
  To run “fullscreen”, press Alt+Enter on the PC keyboard at runtime.
  Press Alt+Enter, again, to return to a window.
  If you prefer a different default window resolution, edit the configuration file:
  - Open the configuration file as in step 3 of “Installing DOSBox... ” above.
  Find “windowresolution=original” and try changing it. For example,
  “windowresolution=1280x960” will double the window size. (You will need to alter “output=surface” to one of the other values listed in the comment just above it. e.g. “output=opengl”)
  - Save the edited file (File menu > Save)
• The emulated processor’s speed can be changed, too:
  - Ctrl+F11 decreases, Ctrl+F12 increases the speed in steps. (Press more than once as required at runtime). Or the default value can be changed by editing the configuration file. (Find the “[cpu]” section.)
• For a list of the most useful DOS commands, type “help” at the command prompt (without the quotes). “help /all” gives a complete list.

1. Download “pegem2.zip” from the CCS website. Extract all files into a new folder, called “Pegasus”, say.
2. Copy or move the Pegasus folder into your DOSems folder.
3. Load DOSBox by double-clicking the desktop shortcut (or find it via the Windows Start button).
4. Within the DOSBox window, start the Pegasus emulator:
   C:\> cd Pegasus
   C:\PEGASUS> PegEm2
   The emulator loads and is ready to use.
   
   Note: PegEm2’s interactive graphical user interface (GUI) opens after typing ‘S’ for ‘Simulate’ (as shown on the displayed menu). The GUI has an illustrated hand, the forefinger of which is a graphical cursor for operating the dials and handswitches. The Windows cursor does not automatically associate with the graphical cursor. To make that connection, press Ctrl+F10. This will lock the PC’s cursor to the tip of the forefinger (and will confine it to the DOSBox window). To release the Windows cursor afterwards, press Ctrl+F10 again.