Asking what Y J Saver is on DDF is like asking what binary is when you walk into google's hq.
Disclaimer: I have no idea what they are myself I just know that it's the mama lashon over here.
Oh binary very simple think of switches that could be two positions on/off every bit is 8 bytes every byte is a switch bingo!
2 to the power of 8 = 256 thats why everything jumps
4*256 = 1024
2^0 = 1
2^1 = 2
2^2 = 4
2^3 = 8
2^4 = 16
2^5 = 32
2^6 = 64
2^7 = 128
2^8 = 256
2^9 = 512
2^10 = 1024
So these 1024 Bytes is equal to 1 KiloBytes. And 1024 KB is equal to 1 MB and so on
IE 11111001 = 128,64,32,16,8,4,2,1 128+64+32+16+0+0+1 = 249 Or (256 -(4+2)) = 249