Downloading, Installing, and Using

Virtual Televisor for DOS

Early phases in the development of the DOS Virtual Televisor software suggested that a relatively fast Pentium-class system (>1.6 GHz) would be required to run the program. This was a discouraging development as it would significantly limit the number of people who could use the system. It now appears that much of the problem was related to an unrecognized problem with the interface clock circuit and, once that was fixed, the software is much less demanding in terms of CPU clock speed. The beta software is now running quite well on an old 75 MHz Pentium system (use to display and save the image shown above). Although the absolute low-end of the CPU speed range has not been determined, it is evident that the Virtual Televisor software should run on most Pentium-based (or equivalent) desk and laptop systems! Note that, based on earlier tests on the time required for writing to the screen, I would not expect the software to run on 486 or 386 systems.

 Downloading Virtual Televisor

Clicking on the heading for this section will start the download process. You will be prompted as to where to save the vtvinst.exe file. For the moment, any convenient directory will do as long as you can remember where you put it when it's time to install the software. How you install the Virtual Televisor software depends on which of the many versions of WindowsTM is running on your computer. To determine which procedure to follow, perform the following operations from your normal Windows screen:

Look at the options provided to see if there is one that essentially says Restart Computer in MS-DOS. If so, use the DOS Installation option below. If the DOS reboot option is not shown, use the Windows Installation option below. In both cases, [ENTER] indicates that you should hit the ENTER key on your keyboard.

DOS Installation and Startup

Installation

If there is an MS-DOS icon on your desktop, simply double-click on the icon and skip steps 1-3 below.

(1) Click on START

(2) Click on PROGRAMS

(3) Double-click on MS-DOS

(4) type cd\path and [ENTER] where path is the path to the directory/folder where you have save the downloaded vtvinst.exe program

(5) Type vtvinst and [ENTER] to unzip the file.

(6) Type dossetup and [ENTER]

 At this point your computer will get very busy for a few seconds as it creates a new folder (vtv), copies the extracted files to the new directory, and erases the extracted files from the directory where the downloaded file was stored. When the utility is done, if you look at the contents of folder vtv (with either the DOS dir command or using Windows Explorer), you should see the following files, although not necessarily in this order: vtvdos.exe - the Virtual Televisor program

vtv.dat - image header data file

vtv.bin - program menu data

 The utility has also left a copy of the original vtvinst.exe file in the directory where you originally downloaded it. This means you can repeat the installation at any time in the future. It is also possible to transfer this file to another computer for the Virtual Televisor installation on any number of machines.

Operation

The program MUST be run in a pure DOS environment. DOS, running under Windows, is completely unsuited for two primary reasons:

Thus, we must reboot the system in DOS in order to run the Virtual Televisor: (1) Click on START

(2) Click on Shut-down or its equivalent

(3) Click on Restart in MS-DOS or its equivalent

  Once the computer re-boots, you should see either the root directory prompt (c:\) or the Windows directory prompt (c:\windows). In either case, (4) Type cd\vtv and [ENTER]

(5) Type vtvdos and [ENTER] and the Virtual Televisor program will start.
W95/98 Enhancement

The instructions shown above represent the most basic way of running the software under DOS, but there is a fancier option for W95/98 users that lets the software emulate a standard Windows program. There are a number of extra installation steps (using your mouse) once you have gotten this far, but the convenience is certainly worth it.

(1) Boot and run Windows Explorer

(2) Left-click on the VTV folder

(3) Right-click on the VTVDOS program icon

(4) Left-click on Properties

(5) Left-click on the PROGRAM tab

(6) Left-click the Advanced box

(7) Check the MS-DOS mode box

(8) Un-check the Warn before entering MS-DOS mode box

(9) Left-click on OK

(10) Left-click on Change Icon

(11) Left-click on Browse

(12) Find the original folder where you stored the vtvinst file and open it

(13) Double left-click on the little televisor icon

(14) Left-click on OK

(15) Close the Windows Explorer window and then restart it

(16) Open the VTV folder

(17) Left-click and hold on the televisor shortcut icon and drag it on to your desk-top

(18) Close Windows Explorer and place the VTVDOS icon wherever you wish on your desktop.


Now to run the program, just double-click the televisor icon in the normal Windows fashion, the system will restart in MS-DOS with no additional prompting, and the VTVDOS software will run. When you quit the program. Windows will automatically restart!

You can now proceed to the section on Virtual Televisor Operation.

Windows Installation and Startup

 If you are reading this, your computer is probably running WindowsXP. The most current versions of Windows do not run with DOS in the background and, although they can run DOS in a window (usually referring to "Command Prompt" instead of DOS), this is not adequate for running the Virtual Televisor. Fortunately, the operating system does let you create a "boot disk" using the <A> drive that you can use to restart the computer in the DOS mode. The boot-disk has some serious limitations, as we shall see, but we can work around them.

Making the DOS Boot Disk

    (1) Insert a floppy disk (3.5-inch/1/44 Mb) into your <A> drive. It doesn't
        have to be blank, but it will be when we are finished, so don't use a disk
        with valuable files without backing them up first.

    (2) Click on Start

    (3) Click on My Computer

    (4) Click on the icon for the A-drive

    (5) Click on File

    (6) Click on Format

    (7) Click on the MS-DOS startup box

The A-drive will then start grinding away as the disk is formatted and prepared. When the Format Complete window appears, close all the outstanding windows on your desktop.

Installing the Virtual Televisor

(1) Make sure the new start-up disk is still in the A-drive.

(2) Click on Start

(3) Click on the Run icon

(4) Type c:\path\vtvinst and click on OK

 where path represents the folder where the vtvinstal.exe program was saved. The program will execute and unzip the files. When the program is finished, repeat steps 1-3 above. Next type winsetup and click on OK. At this point your computer will get very busy for a few seconds as it copies the extracted files to the new start-up disk and erases the extracted files from the directory where the downloaded file was stored. . When the utility is done, if you look at the contents of your boot disk (A)  (with either the DOS dir command or using Windows Explorer) you should see the following files, although not necessarily in this order, in addition to the files that were created when the boot disk was made:

                        vtvdos.exe - the Virtual Televisor program
                        vtv.dat - image header data file
                      vtv.bin - program menu data
                      autoexec.bat - batch file to launch the Virtual Televisor program

The utility has also left a copy of the original vtvinst.exe file in the directory where you originally downloaded it. This means you can repeat the installation at any time in the future. It is also possible to transfer this file to another computer for the Virtual Televisor installation on any number of machines.

Operation

The program MUST be run in a pure DOS environment. DOS, running under Windows, is completely unsuited for two primary reasons:

Thus, we must reboot the system in DOS in order to run the Virtual Televisor:

Place the DOS start-up disk into the A-drive.

    (1) Click on Start

    (2) Click on Turn Off Computer or equivalent.

    (3) Click on Restart Computer or equivalent.

The system will now reboot and auto-execute from the A-drive. Once the computer starts to initialize, you can proceed to the section on Virtual Televisor Operation.

Virtual Televisor
Operation

The software takes care of a number of housekeeping activities as it boots, the most important of which is the examination of the three possible parallel port addresses, looking for a signal from the interface. If an interface is not detected, the program will display an error screen listing the various common reasons why an interface might not be detected. terminate as it cannot function in the absence of a working interface. If this happens, there are a number of possibilities to investigate:

(1) You did not have the interface connected

(2) Power was not applied to the interface

(3) The interface clock is not functioning

(4) The interface cable is defective

(5) If you are using a parallel port switch to share the port with a printer, the switch may not be set properly.

 If the problem is easily recognized, you can fix it and key [T] to retest the ports. If you don't know why the interface test failed, simply key [Q] to quit the program. The program will not run in the imaging mode without a functioning interface.

When a working interface is found, the system next displays a basic text screen that gives information about what you can and can't do with the software. Hitting any key will terminate the text display and take you directly to the main display menu:



This screen-capture image shows the general layout of the screen, with the four program options along the top edge of the screen and the image display area at the center.

 Run

When the program first boots, it does not attempt to display images until you key [R]. The same is true if you have used any of the other options while displaying images. When using the interface for the first time, the video gain control will probably be at minimum (max. CCW = wiper at ground). If you key [R] at that setting, no image will be displayed. However, as the video gain control is advanced, the display will start to trigger and an image should be visible, assuming, of course, that you have a video signal at the input.


LOW            GOOD        HIGH

The control should be set at a point that provides a good grayscale range. If the control is set too low (left, above), the image will be dark and no tonal values will approach true white. The center image shows nearly optimal GAIN adjustment, while in the case of the right image the control is set too high. In the latter case the result will be washed-out images and, at maximum gain, the loss of sync lock. Optimal adjustment is somewhat subjective and you have the option of making adjustments to optimize individual pictures.

The three other action options can be implemented by keying the highlighted letter of the desired operation. The input is not case-sensitive.

Frame

To minimize interline jitter, the program operates in a synchronous mode. While line sync will be maintained indefinitely, frame sync can be lost if the video data are interrupted, there is a change in the video source, or just an editing break. If frame sync is lost:

keying [F] will restore proper frame alignment.

Save

Keying [S] during active imaging will freeze the current display, the indicator in the upper right of the display will go on to indicate that your keystroke was received, and the current image will be saved using a specific format for the file name:

HHMMSS.BMP

where the final name is constructed from the hour (HH), minute (MM), and seconds (SS) corresponding to the time that the image was saved. This makes it extremely unlikely that you will ever have a conflict with duplicate filenames. The images are saved as 80 x 120 bit-map files and it is assumed that they will normally be archived using standard photographic software. Images can obviously be renamed to suit whatever file system you wish to maintain. Because the image files are small (~10K), the boot disk can store approximately 60 such images before it is full. It is assumed that the operator will periodically move images from the boot disk to other drives for long-term archiving or delete unwanted images as they accumulate, so filling up the boot disk should not be a problem.

Quit

Hitting the <Q> key will return you to the DOS operating system. The program can be rebooted from DOS by simply typing vtvdos and [ENTER], or you can choose to return to Windows. To exit DOS:

Alternative to

a DOS Boot-disk

One of the reasons that you need to install the program and associated files on your floppy boot disk is that DOS is not part of the Windows 2000, NT, or XP environment. These advanced versions of Windows use a different file allocation system, so when you use the DOS boot disk, it recognized the A-drive but will ignore the C-drive on your system. In experimenting with the capabilities of my XP computer when running DOS, I discovered an interesting anomaly. If you have a USB drive or equivalent (ZIP drive, card reader, etc.) on your system, when the computer reboots from the DOS start-up disk, the computer DOES recognize the USB drive and allocates it to drive C!

I have an 8 Mb flash card left over from a digital camera upgrade and I have a USB card reader. Under Windows this device appears as drive E. If I copy all the program files to the Flash card (drive E) and make the following changes to the autoexec.bat file on the DOS start-up/boot disk:

              c:
                vtvdos

The system will boot from the DOS start-up/boot disk but the program will run out of the flash card. Since the flash card is a virtual drive, operation is much faster than would be the case when running from the A-drive. This is a handy trick for running any older DOS software and, since flash cards (and their equivalent) are available up to at least 512 megabytes, there is essentially no limit to the size of the programs you can handle this way.