Timeline for Why do PCs boot in 720x400 resolution?
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| May 20, 2021 at 7:58 | comment | added | supercat | @EuroMicelli: Do alternate code pages avoid putting any characters that fill in the eighth pixel but shouldn't fill in the ninth rightward in the 0xC0-0xDF range? | |
| May 20, 2021 at 4:49 | comment | added | Euro Micelli | More precisely, C0 is the first character in the box drawing range that has a “right-pointing end” and therefore needs extending. The lower B3-B9 only point up, left and or down so they didn’t need to be stretched to keep lines continuous. | |
| May 19, 2021 at 7:05 | history | edited | user3840170 | CC BY-SA 4.0 |
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| May 18, 2020 at 19:02 | comment | added | Michael Karcher | @StarCat Tiny detail to add: If you connected the EGA card to an MDA monitor (and set the dip switches appropriately), it switched to MDA timings, and also had the 720x350 text mode. | |
| May 18, 2020 at 8:23 | vote | accept | aybe | ||
| May 18, 2020 at 7:35 | comment | added | Justme | Yes, only VGA text mode has 720x400 active area resolution. And the text mode cannot be distinguished from other 400-line modes. | |
| May 18, 2020 at 6:34 | comment | added | StarCat | @Spektre, If you mean all those cards had a 80x25 text mode, you’re correct. But they all had different character / pixel resolutions. The MDA and Hercules had 720x350 (9x14 pixel characters), the CGA had 640x200 (8x8 pixel characters). EGA had 640x350 (8x14 pixel characters). | |
| May 18, 2020 at 6:00 | comment | added | Spektre | IIRC it also predates VGA .... you know there where CGA/EGA/MDA and herkules before VGA and the Text mode 80x25 was on EGA too and I think even CGA had that. | |
| May 17, 2020 at 20:11 | comment | added | user722 | Only characters in the range 0xC0 to 0xDF get the 9th pixel column repeated, which not uncoincidentally is the box drawing character range. Text characters don't have this repeat so they can fill the entire 8x16 character cell while still having one column blank between characters. | |
| May 17, 2020 at 15:46 | comment | added | the busybee | @Jonathan Yes. :-D I remember using StarOffice in DOS and text mode. Moving the mouse cursor gives "funny" effects. | |
| May 17, 2020 at 14:44 | comment | added | Jonathan |
The 9th column in VGA text mode would show on areas made of block characters ░▒▓ (176/177/178). I made a special font where each line would have 3 dots, so they'd align on the 9-pixel grid. The 9th column would also be seen on Font based "graphical" cursor
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| S May 17, 2020 at 12:40 | history | suggested | the busybee | CC BY-SA 4.0 |
Add a note about the character set
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| May 17, 2020 at 12:24 | review | Suggested edits | |||
| S May 17, 2020 at 12:40 | |||||
| May 17, 2020 at 9:23 | history | answered | StarCat | CC BY-SA 4.0 |