What does the lock switch do on an SD card? Did you ever wonder what the Lock switch on an SD card actually does? I've presumed it switches something inside the card itself. Well...

nadelewitz Loc: Ithaca NY

Did you ever wonder what the Lock switch on an SD card actually does?

I've presumed it switches something inside the card itself.

Well, thanks to getting my hands on an old transparent SanDisk SD card, I saw that the switch doesn't do that.

It is just a sliding tab. The actual electrical switch is inside the card slot of the camera, card reader, computer, wherever. The position of the card's switch just presses the REAL switch in the card slot, or not, depending on its position.

But BEWARE.....I discovered a couple of my cheapie USB-SD Card readers do not have the switch in them, and "locking" the SD card DOES NOT write-protect the card.

There's always something to learn about the technology we use, huh!

rjaywallace Loc: Wisconsin

UHH member “nadelewitz” -
Respectfully, I suggest taking your question to websites for SanDisk, Delkin, etc.
What does it really matter what gets triggered where? The lock tab works.

rmalarz Loc: Tempe, Arizona

On all of my cards, it prevents writing data to the card. None of my card readers have a switch.
--Bob

nadelewitz wrote:

Did you ever wonder what the Lock switch on an SD ... (show quote)

nadelewitz Loc: Ithaca NY

rjaywallace wrote:

UHH member “nadelewitz” -
Respectfully, I suggest taking your question to websites for SanDisk, Delkin, etc.
What does it really matter what gets triggered where? The lock switch works.

You didn't read what I said, apparently.

I did not have a question at all.

Let me say it louder for you.....

I DID point out that the lock switch DOES NOT DO ANYTHING (WORK) IN A CARD SLOT THAT DOES NOT HAVE THE ELECTRICAL SWITCH.

Have a nice day.

nadelewitz Loc: Ithaca NY

rmalarz wrote:

On all of my cards, it prevents writing data to the card. None of my card readers have a switch.
--Bob

Jeez, why are people making an argument out of this?

I OBSERVED AND TESTED what I was saying in the original post.

I HAVE card readers that DO NOT have the switch in the slot, and DO NOT prevent writing when the card is "locked".

Just trying to offer some advice that could save someone some aggravation.

You're welcome!

Blaster34 Loc: Florida Treasure Coast

nadelewitz wrote:

You didn't read what I said, apparently.

I did not have a question at all.

Let me say it louder for you.....

I DID point out that the lock switch DOES NOT DO ANYTHING (WORK) IN A CARD SLOT THAT DOES NOT HAVE THE ELECTRICAL SWITCH.

Have a nice day.

...and maybe a little slower for rjay...

ClarkG Loc: Southern Indiana USA

The card reader switch should “work” in the camera to prevent any more photos from being saved onto the card.
It may not “work” in much older versions of card readers.

Bill_de Loc: US

nadelewitz wrote:

Did you ever wonder what the Lock switch on an SD ... (show quote)

Good observation! Never would have given it a second thought.

--

Soul Dr. Loc: Beautiful Shenandoah Valley

Also if the tab is in the lock position, you will not be able to rename file on card before downloading.
I know because one of my laptops will push the tab in lock position when inserting the card in the SD slot.

And, rjaywallace you need to take your meds and lighten up!

will

rjaywallace Loc: Wisconsin

nadelewitz wrote:

You didn't read what I said, apparently.
I did not have a question at all.
Let me say it louder for you.....
I DID point out that the lock switch DOES NOT DO ANYTHING (WORK) IN A CARD SLOT THAT DOES NOT HAVE THE ELECTRICAL SWITCH.
Have a nice day.

FIRST, THERE IS NO “SWITCH” ANYWHERE. THERE IS A SLIDING TAB THAT INTERACTS WITH SOMETHING, PERHAPS A ROBIN FLYING OVER HEAD, THAT PREVENTS DATA FROM OVERWRITING THE MEMORY CARD. AS I SUGGESTED, PERHAPS MEMORY CARD MANUFACTURERS CAN EXPLAIN IT TO YOU.

nadelewitz Loc: Ithaca NY

ClarkG wrote:

The card reader switch should “work” in the camera to prevent any more photos from being saved onto the card.
It may not “work” in much older versions of card readers.

Age has nothing to do with it. The switchless card readers I have are brand new.

rjaywallace Loc: Wisconsin

Soul Dr. wrote:

Also if the tab is in the lock position, you will not be able to rename file on card before downloading.
I know because one of my laptops will push the tab in lock position when inserting the card in the SD slot.

And, rjaywallace you need to take your meds and lighten up!
will

Where there’s a will there’s a way.

nadelewitz Loc: Ithaca NY

rjaywallace wrote:

FIRST, THERE IS NO “SWITCH” ANYWHERE. THERE IS A SLIDING TAB THAT INTERACTS WITH SOMETHING, PERHAPS A ROBIN FLYING OVER HEAD, THAT PREVENTS DATA FROM OVERWRITING THE MEMORY CARD. AS I SUGGESTED, PERHAPS MEMORY CARD MANUFACTURERS CAN EXPLAIN IT TO YOU.

I give up with you. You can SEE the switch in the card slot. This is not an intangible "something".

Having a bad day? Perhaps you need a new eyeglass prescription.

Soul Dr. Loc: Beautiful Shenandoah Valley

How the lock tab on SD card works.....

In fact, the lock switch has no bearing on the internals of the SD card at all. If you rip an old SD card apart you will see that it is nothing more than a little plastic slider that rides in a groove, and does not affect the electronics of the card itself.

Its position is sensed by a small switch -- often just a spring-loaded little bit of metal -- inside the card slot on the card reader. When the switch is in the "lock" position it engages the switch in the reader and it tells your computer (or whatever device), "Hey, this thing is locked, don't write to it."

It is 100% up to the manufacturer of the reader to ensure that the lock functionality works and is supported. Many cheap Chinese knockoff card readers, especially those that do not fully encapsulate the card and leave it sticking part or most of the way out of the slot, don't support the lock switch at all. You can leave the switch in whatever position you want and it will have no effect.

You might find that an old and well-worn card will have a lock switch that doesn't hold its position anymore, and may even get toggled just from the force of putting the card in a reader in the first place. You can just glue it in the "unlocked" position or carefully pull it out with a pair of tweezers to no ill effect (though the management disavows all responsibility if you snap your brand new $200 512 gig card in half). That card will never be locked again.

nadelewitz Loc: Ithaca NY

Soul Dr. wrote:

How the lock tab on SD card works..... br br In f... (show quote)

Thank you for concurring in what I originally said. I hope rjaywallace gets it now.