There are two ways to make a USB stick read only. One way is a universal solution and is 100% permanent, the other way is PC specific and a good deterrent. When we say 100% permanent, this means the USB stick is read only (write protected) on all computers, whether it be a Mac, PC, Linux, etc type computer, the USB is read only and the status cannot be changed. The other method flags a USB device to be read only in relationship to the PC it is connected to so that whenever that USB stick is connected to that computer, it makes the USB read only and blocks all write commands to the device.
Most times an IT manager or content owner wants the USB stick to be read only so the files cannot be deleted or formatted off the drive. Another reason for making a USB read only is for the original files to remain the same and blocks the ability for files to be changed or manipulated. Finally, it’s smart to have USBs read only so that virus’ don’t jump onto the drive and possibly spread to other computers.
Let us start with the less permanent way because it’s easier to do and doesn’t require any specific hardware. You will need a Windows7 machine or higher. The Windows7 machine will have DiskPart utility which allows us to perform all sorts of cool things to flash drives, like setting write protection.
- Connect the USB to your Windows computer.
- To begin, go to your Windows Start and in the Search Field type â€œcmdâ€
This will run your Command prompt.
- Next, you will want to get to the C root of the Command prompt and if you are signed in as a user you can simply type cd\ this will get you back to the root of the C drive.
- Type DISKPART
- Type LIST DISK
Now you will need to find the USB stick connected to your PC. Most likely it’s DISK 1
Is Checksum or CRC better for checking data written to USB flash drives?
This post is to give the general user an idea of what verification method is better for writing data to a flash drive. There are reference links at the bottom of this post which dive much deeper into the two methods of verification if this simple overview is not enough.
The short answer is Cyclical Redundancy Check or CRC is the best method for checking data written to a USB flash drive.
Many believe a checksum is the best method to verify data written to a flash drive (most popular is MD5). I believe this is favored because it is easier to understand how the verification works, and also easier to implement. However, there are flaws in checksum verification and therefore not suitable for verification of data written to a flash drive.
What is the difference between Checksum and CRC verification? The checksum method uses addition in its math calculations to check whether all data was written correctly. CRC uses long division in its math calculations to check whether all data was written correctly. It is worth noting I am talking about binary long division, not the school-yard long division you so fondly remember.
Checksum methods will calculate the total bits in a packet of data and include that total checksum amount when the data is sent over communication lines. The receiver will then look at the packet, read the checksum value and then perform the same calculation to make sure everything adds up. If the calculation on the receiverâ€™s end matches the value passed in the packet, all is good. The problem is a high probability that somewhere between the sender and receiver the bits of data are changed, corrupted or swapped yet still turn a correct checksum value after calculation on the receiving end.