Whether you’re formatting an internal drive, external drive, or USB flash drive, Windows makes it possible to choose between NTFS and exFAT formats. In this guide, we’ll go over the simple steps to formatting a USB drive and which format is best for certain situations.
Most of the time formatting a flash drive is a very simple decision. There are only two situations where you should take consideration on what format to use. Here are the details:
Note: This article is focused towards Windows and Mac operating systems.
The file formats available for a flash drive are:
- FAT (also called FAT16)
- HFS (Mac only)
Flash drive manufacturers format a drive as either FAT or FAT32. Any device of 2GBs or smaller will be formatted as FAT and any USB over 2GBs will be formatted as FAT32.
These two formats are the best file system for removable drives like flash drives because they support the quick disconnect function and chances are very slim you will destroy the device or files if you unplug the USB without using the Eject function (in Windows) or Un-mount function (in Mac).
The one huge limitation with FAT and FAT32 is the single file size limitation. If a single file is larger than
Sometimes you will connect a USB to the PC and get an error message saying the drive has a GPT Protective Partition and you cannot format the drive. Here is the fix to resolve the issue:
First, what is a GPT USB stick? The GUID Partition Table (GPT) is the successor to the Master Boot Record. The MBR was created by IBM back in the early 90s. The problem with MBR is the limitation to partition table sizes which is 2 Terabytes.
Since there are no 2T USB flash drives (at the time of this post), there is no need to use GPT as your partition table.
Removing the GPT Protected Partition can be accomplished through the Windows Diskpart program.
- Determine the Disk Number for the USB GPT-protected drive. To do this, perform the following:
- Right-click on (My) Computer.
- Choose Manage.
- Select Disk Management (listed under Storage).
- Look for the drive that is identified as GPT and note the Disk number (such as Disk 1).
Format USB GPT Protected Partition
- Now, open a Command Window. From the command prompt, type diskpart and press Enter.
- The diskpart prompt will open.
- From the diskpart prompt, type list disk and press Enter. A list of disks will appear in a text format. You will return to the diskpart prompt.
- From the diskpart prompt, type select disk disknumber (in this example from the screen shot above, you would type select disk 1)and press Enter. A message appears saying that the disk is selected. You will return to the diskpart prompt.
- From the diskpart prompt, type clean and press Enter. At this point the drive’s partition and signature a removed. You will return to the diskpart prompt.
- From the diskpart prompt, type exit and press Enter. Type exit once more to close the Command Window.
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 of 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 “cmd”
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
This is a great video that explains how flash memory works. Granted, the video is very technical but does work through the concept of reading and writing data to flash. So if you have the 17 minutes to use, I suggest giving this a watch. The video does cover SLC, MLC and TLC memory and how each of these technologies read and write with the different layers of a floating gate device like NAND.
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