I'm on Ubuntu 11.04 (upgraded from 10.10) and suffering really high bootup times. It got so annoying, that I decided to dive into bootchart analysis myself. Therefore I installed bootchart and restarted the system which generated this chart.

However, I'm not really experienced in reading such stuff. What causes the long bootup sequence?

Edit:

Here is the output of hdparm -i /dev/sda:

/dev/sda:

Model=SAMSUNG HD501LJ, FwRev=CR100-12, SerialNo=S0MUJ1EQ102621
Config={ Fixed }
RawCHS=16383/16/63, TrkSize=34902, SectSize=554, ECCbytes=4
BuffType=DualPortCache, BuffSize=16384kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes:  pio0 pio1 pio2 pio3 pio4 
DMA modes:  mdma0 mdma1 mdma2 
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
AdvancedPM=no WriteCache=enabled
Drive conforms to: unknown:  ATA/ATAPI-3,4,5,6,7

* signifies the current active mode

And here the output of hdparm -tT /dev/sda

/dev/sda:
Timing cached reads:   2410 MB in  2.00 seconds = 1205.26 MB/sec
Timing buffered disk reads: 258 MB in  3.02 seconds =  85.50 MB/sec