An additional factor must also be included when dealing with "burned" discs — COMPATIBILITY. Commercial discs are mechanically stamped creating physical pits on the disc surface that reflect or don't reflect a "read laser" while "burned" discs rely on chemical dyes that change color when exposed to a "write laser" and then reflect or don't reflect the "Reade laser". The mechanically stamped discs are highly reliable with virtually any drive but burned discs are subject to a number of variables including:
- The specific chemical composition of the dyes used in the disc
- The specific frequency of the "write" laser and that can change with age and use
- The specific frequency of the "read" laser and like the "write" laser that too can change with use
- The quality of the reflective layer of the drive which can oxidize with age and thus becomes less reflective
As a result whether a given burned disc will play properly on a given player is a bit of a crap shoot. I know of innumerable cases where a given burned disc would play properly on one player but not another. Changing disc brands (or even models within a brand) might create a disc that would play on both players or it could reverse which player the new disc would play on or in one case the new disc would not play on either player.
I don't know the specific statistics today but at one time the odds that a given burned disc would play on 4 out of 5 players on the average. Those odds were for regular CDs and DVDs but the only difference between them and BlueRay is BlueRay uses a much higher frequency (ie.
shorter wavelength) laser in order to pack more data into the same physical space and that can only increase the odds of not working. The better (generally read better as more expensive) the burner and the better the player and the better the blank media the better the odds. (This is only one of the many reasons behind the move from optical media to solid state and data streaming.)
I'm told that all USB drives are formatted as FAT32. The 8 drives that I have
USB is a drive interface independent of the storage media. For example I have Hard Drives, Solid State Drives, SD cards, Thumb Drives, and CD/DVD drives that have USB interface to my computer. I believe you are using USB
to refer to a "USB Flash Drive" (a.k.a. Thumb Drive). FAT32 formatting is commonly used for smaller USB Flash Drives (less than 32 GiB), but for higher capacity Flash drives ExFAT
format is more commonly used. ExFAT is specifically optimized for use with Flash Drives and XD Cards, has no realistic limit on the number of files and file sizes, and is compatible with both Windows and MacOS. It is the default file system for all SDXC Cards. Apple's Disk Utility is capable of formatting a USB Flash Drive as ExFAT and MacOS can read and write to ExFAT drives.
USB Flash Dives, SD cards, and SDXC Cards may be formatted any format you choose. I have Flash drives and SD cards formatted FAT, ExFAT, MacOS Extended, and APFS. (APFS works quit well on a Flash Drive if you are only dealing with Macs running Sierra or later.)