Can USB be reused after install

[visruth]

Ok

Thanks David , adam, jimbo -

So, most of the doubts are cleared but still some remains,

According to MSFT sources, Its not possible to back up system image or files alone to removable drive if it's not ntfs partition.
If so, one question - how come David could do it in FAT32 eventhough one main file is split into many?

Next, if gparted partitioning & subsequent formatting don't work for Windows, so it means whole USB can only be formatted as ntfs or fat32 right and then copy the Windows ISO along with other files into it?

 

[visruth]

Keep in mind that if your installing Windows in UEFI mode, some PC's require the thumb drive to be formatted in FAT for it to work. If you format the thumb drive in NTFS you may not get the UEFI install option in the boot menu and won't be able to do a UEFI install. I prefer NTFS over FAT or FAT32, especially for large capacity thumb drives.

Wonder why only some have that requirement & some are okay if it's FAT or NTFS - for UEFI .

 

[topgundcp]

@David
I don't know anything about ISOs.

ISO file is a compressed file just like a compressed ZIP or compressed RAR file which contains files/folders structure in its own format. In addition, you can mount an ISO file to a virtual CD/DVD. Winzip/Winrar do have the ability to extract files/folders from an ISO file also.

@vsruth

For windows iso to work, I've heard sometimes FAT32 only works, is that correct?

When format the USB for Windows installation disk, you should format with FAT32 so it will work under UEFI system since the USB is in NTFS and earlier version of UEFI can only boot from FAT32. If you use MBR style installtion style then it won't matter.

So EACH FILE size is limited to 4GB in Fat32 ?

True. In computer world, we use binary number ie. 0 & 1 and base 2 numbering system so everything is in multiple of 2's. In real world we use base 10 numbering system.
For example:
Base 10: 1K = 10^3 = 10x10x10 = 1000
Base 2 : 1K = 2^9 = 2x2x2x2... (9 times) = 1024

So, FAT32 can only address up to 2^31 (32 times starting with 0) which yields: 4,294,967,295 = 4000K = 4 GBs. That's why the file size is limited to 4GBs

Allocation unit size is default 4096 bytes? It's same for both fat32 & ntfs?

It's up to you how you want to configure it.

In terms of space efficiency, smaller allocation unit sizes (also called cluster size) result in less space wasted but slower (more fragments on the disk).

Larger allocation unit sizes result in more space wasted but faster.

For example: let's say you have a file with a size of 1000 bytes (characters). Depending on how you configure the allocation unit size so for a 1000 bytes file size:
if allocation unit size = 2048 will occupy 2048 bytes on the disk ===> wasted space = 2048 - 1000 = 1048 bytes
if allocation unit size = 4096 will occupy 4096 bytes ====> wasted space = 4096 -1000 = 3096 bytes

Comparing between 2K & 4K cluster sizes. When saving a file to the disk, for larger cluster size, it will take half disk access time to write the file resulting faster

Hope this helps !!!

 

[visruth]

@topgundcp

That is the perfect explanation :thumbup:
It may be foolish doubt, this has to be cleared -
is certain allocation unit size restricted to specific formatting style,
I mean : is fat32 formatting required to be done with 8192 bytes & ntfs to be done with 4096 bytes allocation unit size?

Or is allocation unit size in no way related to format style?

 

[topgundcp]

is fat32 formatting required to be done with 8192 bytes & ntfs to be done with 4096 bytes allocation unit size?

No

Or is allocation unit size in no way related to format style?

Will format according to the cluster size set.

 

[robin0800]

Glad I saw this thread as I was using a sandisk 16Gb usb drive for Ready Boost could not understand why it only used 4Gb but of course it was Fat32. Just converted it to NTFS and Ready Boost is now using all of it.

 

[visruth]

is fat32 formatting required to be done with 8192 bytes & ntfs to be done with 4096 bytes allocation unit size?

No

Or is allocation unit size in no way related to format style?

Will format according to the cluster size set.

Okay, that's cleared up for now , thank you

 

[visruth]

Glad I saw this thread as I was using a sandisk 16Gb usb drive for Ready Boost could not understand why it only used 4Gb but of course it was Fat32. Just converted it to NTFS and Ready Boost is now using all of it.

Ok, so ReadyBoost too need NTFS for larger random access caching
That means the whole flash drive cache file is a huge single entity rather than multiple entities,

 

[alphanumeric]

Keep in mind that if your installing Windows in UEFI mode, some PC's require the thumb drive to be formatted in FAT for it to work. If you format the thumb drive in NTFS you may not get the UEFI install option in the boot menu and won't be able to do a UEFI install. I prefer NTFS over FAT or FAT32, especially for large capacity thumb drives.

Wonder why only some have that requirement & some are okay if it's FAT or NTFS - for UEFI .

It depends on the BIOS. I can use NTFS and install in UEFI on my ASUS laptop but I have to use FAT 32 on my Wife's Acer laptop for UEFI to work. My two desktop PC's don't have a UEFI BIOS so I can use either. I normally use the Windows 7 USB DVD Download tool to create my bootable thumb drives. It formats in NTFS. I did my first clean install on my ASUS laptop using that tool and installed in UEFI mode with no issues. I was then told in another thread that you can't do that? Well I did, so that's how I now some PC's can do it with NTFS. Anyway, it turned into an almost endless debate with another forum member who refused to believe me. Go figure?

 

[visruth]

thanks for that alpha,
So BIOS decides that, means it depend on BIOS , if uefi boot device option is to be down when the USB is NTFS formatted for Windows installation, right?

windows 7 usb tool have no other additional option for formatting, only NTFS ?

 

[topgundcp]

thanks for that alpha,
So BIOS decides that, means it depend on BIOS , if uefi boot device option is to be down when the USB is NTFS formatted for Windows installation, right?

windows 7 usb tool have no other additional option for formatting, only NTFS ?

Earlier version of UEFI will only boot with FAT32, later version will accept either. For compatibility, you should format as FAT32.
To create a FAT32 USB, use: Rufus - Create bootable USB drives the easy way

 

[alphanumeric]

thanks for that alpha,
So BIOS decides that, means it depend on BIOS , if uefi boot device option is to be down when the USB is NTFS formatted for Windows installation, right?

windows 7 usb tool have no other additional option for formatting, only NTFS ?

Yes the BIOS has to support NTFS for UEFI install. The Windows 7 DVD Download tool doesn't give you an option to chose FAT32. You pick your ISO file and your destination drive and that's it. I used Rufus to create the thumb drive I use on my Wife's Acer laptop.

 

[visruth]

Ok, thanks topgun, alpha :thumbup: