Why did system font files (.fon) lost some undefined glyphs in Win7

Question

Just made the switch from XP to Win7 on my work PC and I noticed something strange.

Some 'undefined' glyphs are missing from system fonts such as "Courier", "Terminal" and "System" (i.e., those that don't have an icon in the "Font" drop-down in "Character Map").

Character codes 0x81, 0x8D, 0x8F, 0x90 and 0x9D had a small square in XP's version of these fonts, but they are empty (zero width) in Win7.

You can 'type' these characters in notepad by holding down the left-hand [Alt] key, typing their four-digits decimal value (respectively, 0129, 0141, 0143, 0144 and 0157) on the numeric keypad and releasing the [Alt] key. In XP you get an empty square, in Win7 you get a zero-width character - nothing is displayed but moving the cursor with the arrows shows that 'something' is there...

Surely, by now, if it was a bug, someone would have noticed it? Why are they gone?

I noticed this because I often write batch files (.bat) for French speaking audience and to simplify accented characters entry (and box drawing characters) I made a file with both DOS characters and the equivalent Windows one. The missing glyphs correspond to the DOS characters ü, ì, Å, É and ¥.

Answer 1

If they don't have glyphs, then I'd argue that their display is "undefined", which means you cannot rely upon it being the same. Windows 7 might have changed font rendering to better support other Zero-width characters - I doubt anyone but the internal Microsoft team that made the change really knows.

I admit true DOS is just slightly before my time, but all current fonts (including Courier and Terminal) map the described glyphs ü, ì, Å, É and ¥ to 0xDC, 0xEC, 0xC5, 0xC9, and 0xA5, including when displayed inside of cmd.exe (which isn't real DOS). Because of this I'm presuming there is some piece of the puzzle that I'm missing as to what exactly you're doing and what fonts are being used where. (I do see that the font labelled 'System' has the glyphs in the locations you describe them though. Perhaps change the font of your CMD.exe windows to be something with proper glyph support?)