MediaWiki:Sitenotice:
2025-12-29: I have restored the wiki to a backup from the end of November. Starting in September 2025, accesses went form the 800MB-1.2GB range per month to 26GB in September, 42GB in October, and 70GB in November with most accesses originating from China. As soon as I realized what was causing all the access problems in November, I shut it down (it had reached 36GB by then) behind a password/login screen. The database had gotten corrupted, and I tried a restore from just before the spike in access but that didn't work. Thus, end of November. I still have the other daily backups so if there were any important additions in December, let me know and maybe they can be recovered. - Allen H.

Video Display Generator

From CoCopedia - The Tandy/Radio Shack Color Computer Wiki
Revision as of 09:54, 12 February 2015 by Luis46coco (talk | contribs)
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VDG

File:Coco2boot.png
Power-on screen of a CoCo 2

The MC6847 is display generator capable of displaying text and graphics contained within a roughly square display matrix 256 pixels wide by 192 lines high. It can display 9 colors: black, green, yellow, blue, red, buff (almost-but-not-quite white), cyan, magenta, and orange.

Alphanumeric/Semigraphics display

File:Cocobvdg.png
Sample character set display of 6847 VDG

The CoCo is physically wired such that its default alphanumeric display is actually "Semigraphics 4" mode.