Drive Letter 'A' not usable as mount point

[infeo]

Feature request can skip this form. Bug report must complete it. Check List must be 100% match or it will be automatically closed without further discussion. Please remove this line.

Environment

• Windows version: Windows 10 Pro
• Processor architecture: x64
• Dokany version: 1.1.0.2000
• Library type (Dokany/FUSE): Dokany

Check List

• I checked my issue doesn't exist yet
• My issue is valid with mirror default sample and not specific to my user-mode driver implementation
• I can always reproduce the issue with the provided description below.
• I have updated Dokany to the latest version and have reboot my computer after.
• I tested one of the last snapshot from appveyor CI

Description

Don't know if it is a bug or not, but with dokany you cannot use the drive letter 'A' as a mount point. You can find this exclusion in the code:

dokany/dokan/dokan.c

Lines 100 to 102 in 224fc08

	BOOL IsValidDriveLetter(WCHAR DriveLetter) {
	return (L'b' <= DriveLetter && DriveLetter <= L'z') ||
	(L'B' <= DriveLetter && DriveLetter <= L'Z');

My question is now, why is this drive letter excluded? I can't see any reason for this. (I know the drive letters 'A' and 'B' are a little special, see https://superuser.com/questions/231273/what-are-the-windows-a-and-b-drives-used-for#233284).

Best wishes,
infeo

Logs

--omitted--

[Liryna]

Hi @infeo ,

Driver letter A is windows reserved letter for historical floppy disk driver 👍 as you seen on the superuser questions.
The code is just to avoid to get an error from windows later.

[infeo]

That's true, but then 'B' should be also excluded, shouldn't it? Or do i miss something? (With mount point 'B' the mirror example works pretty fine).

Additionally, if you change the code to accept 'A' as a valid mount point, compile and install it, the mirror example runs pretty smooth. Maybe this constraint can be dropped in the next release? :D

[Liryna]

Hi @infeo ,

I see your point 👍 I see no issue remove this if on Windows 7 (lower supported OS) mount with and without mount manager work for A & B.
This code comes from the original dokan code that supported XP.

[Liryna]

Hi @infeo ,

Windows 7 propose the usage and the mount of a driver with the letter A. I have changed the condition to allow A also therefore 👍 af8ddfc

Thank you for your feedback !