I am trying to calculate the max volume and file size for fat 32 and hdfs. for fat32 i have 4096 bytes sector size and 2^32 possible sectors . so 2^32 * 4096 = 1.759218604×10¹³ bytes or 17.6TB for the Volume size. But this should be 16TB according to the texts.
The same for HDFS: i have a block size (sector size) of 64mb and 63 bits to index the sectors and I do the same calculation : 2^63 * 64 = 590.29 YB . But this should equal 512 YB according to the texts . YB = Yota bytes = 10^12TB
I'm not sure where you got your "according to the texts" from. Max volume size for a FAT32 file system is 32 GB for Windows 2000 and 127.53 GB for Windows 98 (Reference)
You also need to be careful with your byte calculations. Make sure you know if the texts you are referring to are using 2^n or 10^n for their reporting. 1 Terabyte (TB) = 10^12 bytes and 1 Tibibyte (TiB) = 2^40 bytes. So, 2^32 * 2^12 (4096) = 2^44 = 16 * 2^40 = 16 TiB.
Similarly, 2^63 * 2^6 (64) = 2^69 = 2^9 * 2^60 = 512 EiB
Your calculation of 590.29 YB is not correct... it works out to EB not YB. 1 EB = 10^18 bytes and 1 YB = 10^24 bytes
It's also worth noting that a lot times TB is used as short hand for TiB.