I lack formal knowledge in Operating systems and C. My questions are as follows. When I try to read first single byte of a file using fread in C, does the entire disk block containing that byte is brought into memory or just the byte? If entire block is brought into memory, what happens on reading second byte since the block containing that byte is already in memory?. Is there significance in reading the file in size of disk blocks? Where is the read file block kept in memory?

Reading file using fread in C

I lack formal knowledge in Operating systems and C. My questions are as follows.

When I try to read first single byte of a file using fread in C, does the entire disk block containing that byte is brought into memory or just the byte?
If entire block is brought into memory, what happens on reading second byte since the block containing that byte is already in memory?.
Is there significance in reading the file in size of disk blocks?
Where is the read file block kept in memory?