Hide Specific Drives in Windows  

For example: To hide both the E (16) and F (32) drives, I would add 16 and 32 together from the table below, and enter 48.

So, how do I decode that value programmatically?!
I mean we have value 48 for (E + F) and we know it of our aspect!, how do I calculate the 48 to get the E & F volume?
Note that not just 48 that would be 49 or 47 !!! So we cannot just minus the 48-32-16=0 to find the volumes !!

Paul Black said:

Hello @hamedn53,
Welcome to TenForums.



I am NOT sure what you mean.

Regardless of what the Drive Letter[s] are, there will be a SINGLE numeric value for them, as per the table in post 1 . . .

Code:

Drive Letter	Decimal Value Data
Show all drives	0
A	1
B	2
C	4
D	8
E	16
F	32
G	64
H	128
I	256
J	512
K	1024
L	2048
M	4096
N	8192
O	16384
P	32768
Q	65536
R	131072
S	262144
T	524288
U	1048576
V	2097152
W	4194304
X	8388608
Y	16777216
Z	33554432
Hide all drives	67108863

So, for example, if you had Drives D + E + F, the value would be 56.

I hope this helps.

Hey Paul, thanks for answering, but I do know that table values.
I meant that; I wrote an app that shows the all mounted volumes on the system, and I also have a tree-view which lists all mounted volumes of the system that has checkbox for each item of the tree-view object.
So, let's assume we did hide drives A+D+E with values of 1+8+16=25. I do know what 25 means by that table, but my app does not know how to handle that. I cannot write all the possibilities of that calculation, so I need an arithmetic algorithms to handle 25 into A,D,E volumes and so on. Am I pointed my opinion clearly?

Paul Black said:

Hello @hamedn53,

I know NOTHING about writing Apps, but can't you use an Array for the values, each being designated a specific number for EACH Drive Letter, like the Table, OR, set a Variable for EACH of the values?

Because of what you are trying to achieve, you might be better off starting your own Thread for this, and just add the link to Post 1 in this Thread so that other members can see what you are referring to.

Actually I couldn't create an array. why? because there is not only 26 options! It is actually 26^26 (i think) mess or clutter!
Yeah, thanks for the advise. That would be great idea! thanks again

Paul Black said:

I know NOTHING about writing Apps, but can't you use an Array for the values, each being designated a specific number for EACH Drive Letter, like the Table, OR, set a Variable for EACH of the values?

Binary math using bitwise operators, makes this problem relatively simple.

D, E, F are the 4th, 5th & 6th letters in the range of A to Z. They each have an ordinal (index) position relative to A.

D minus A = 3 -> 2^3 = 8
E minus A = 4 -> 2^4 = 16
F minus A = 5 -> 2^5 = 32

The binary shift-left operator allows us to express 2^N by shifting the number 1 (same in binary & decimal) N positions to the left. Therefore if we take the bitwise OR operation of each of the letter's ordinal positions relative to A, we get the correct decimal value.

Code:

(1 -shl 3) -bor (1 -shl 4) -bor (1 -shl 5) = 56

To decode the bitmask in the other direction, you could treat it as a 26-bit array and perform a bitwise AND operation to compare each of the possible shifted values.

With the ordinal position of the enabled bits, we can use that same position's offset from A (ASCII 65) to return a new letter.

Code:

for ($i = 1; $i -le 26; $i++) {
    if (( 56 -band (1 -shl $i) ) -gt 0) {
         [char](65 + $i)
    }
}

D
E
F

- - - Updated - - -

If you hate math, here's a PowerShell GUI for you.



The script re-loads the current NoDrives value and marks which drives are already hidden. Checking the Volumes box will alternate between clearing all selections, or selecting all drives. Don't forget to logout to force Windows to update the Explorer views.

The script will self-elevate if you're not running as Administrator. Yes, the flashing CMD windows are annoying but it all works in one script.

NoDrives.bat