General :: Difference Between Buffered Disk Reads And Cached Reads?

I was analyzing the Disk read using hdparm utility. This is what i got as a result.

Code:

# hdparm -t /dev/sda

/dev/sda:

Timing buffered disk reads: 108 MB in 3.04 seconds = 35.51 MB/sec

Code:

# hdparm -T /dev/sda

/dev/sda:

Timing cached reads: 3496 MB in 1.99 seconds = 1756.56 MB/sec I m not sure what does Cache read and buffered disk read mean.