Diagnostic Video Tests B-1Appendix BDiagnostic Video TestsThe Video Test Group of the system diagnostics con-sists of the following eight tests, each of which verifies aparticular video function or group of functions:• Video Memory Test — Checks the integrity of char-acters generated from data in the video memory.• Video Hardware Test — Checks the functions of thecursor register and the horizontal and vertical retracebit registers.• Text Mode Character Test — Checks the video sub-system’s ability to present text mode data.• Text Mode Color Test — Checks the video sub-system’s ability to present color in text modes.• Text Mode Pages Test — Checks the video sub-system’s ability to map and present all availablevideo text pages on the monitor screen, one page at atime.• Graphics Mode Test — Checks the video sub-system’s ability to present graphics mode data andcolors.• Color Palettes Test — Checks the video subsystem’sability to display all available colors.• Solid Colors Test — Checks the video subsystem’sability to show screens full of solid colors. Allowsyou to check for missing color subpixels.All of these tests, except the Video Memory Test and theVideo Hardware Test, are interactive. These interactivetests display images on the monitor screen and requirethe user to respond with the following steps:1. Examine a displayed image for correctness.2. If an image is correct, type y.3. If an image is incorrect, type n.The following sections describe each of the tests in theVideo Test Group.Video Memory TestThe Video Memory Test verifies the integrity of thevideo memory either on the system board or on a videoexpansion card. As the test runs, it describes which64-kilobyte (KB) block of video memory is being tested.When a test is complete, a message indicates whether thevideo memory has passed or failed the test. This test doesnot require any interaction on your part.Video Hardware TestThe Video Hardware Test verifies the operation of thecursor registers and the horizontal and vertical retrace bitregisters. When a test is complete, a message indicateswhether these registers have passed or failed the test.This test does not require any interaction on your part.Text Mode Character TestThe Text Mode Character Test consists of a group of sub-tests that display printable characters and characterattributes. The subtests check character quality and themonitor’s ability to display the characters correctly on itsscreen. A prompt at the bottom of each screen asks theuser to decide whether the display is satisfactory and torespond by typing y or n.If you respond affirmatively to each subtest, the TextMode Character Test passes. A negative response to anysubtest causes the test to fail.
