my box have this by default: (just checked)

/dev/hda:
Timing buffer-cache reads: 128 MB in 0.35 seconds =365.71 MB/sec
Timing buffered disk reads: 64 MB in 1.11 seconds = 57.66 MB/sec

my question:

1.what's Timing buffer-cache reads
2. what's Timing buffered disk reads.
3. is there anything else i can imporve my hdparm setting?
4. i've turn keepsettings on, is that means all settings will be kept even on hardware reboot?
5. what's readonly and what does it do?

currectly my setting is
/dev/hda:
multcount = 16 (on)
IO_support = 3 (32-bit w/sync)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 1 (on)
readonly = 0 (off)
readahead = 8 (on)
geometry = 9729/255/63, sectors = 156301488, start = 0

thanks

-T Perform timings of cache reads for benchmark and comparison pur-
poses. For meaningful results, this operation should be
repeated 2-3 times on an otherwise inactive system (no other
active processes) with at least a couple of megabytes of free
memory. This displays the speed of reading directly from the
Linux buffer cache without disk access. This measurement is
essentially an indication of the throughput of the processor,
cache, and memory of the system under test. If the -t flag is
also specified, then a correction factor based on the outcome of
-T will be incorporated into the result reported for the -t
operation.

-t Perform timings of device reads for benchmark and comparison
purposes. For meaningful results, this operation should be
repeated 2-3 times on an otherwise inactive system (no other
active processes) with at least a couple of megabytes of free
memory. This displays the speed of reading through the buffer
cache to the disk without any prior caching of data. This mea-
surement is an indication of how fast the drive can sustain
sequential data reads under Linux, without any filesystem over-
head. To ensure accurate measurements, the buffer cache is
flushed during the processing of -t using the BLKFLSBUF ioctl.
If the -T flag is also specified, then a correction factor based
on the outcome of -T will be incorporated into the result
reported for the -t operation.