Ubuntu – Slow Ubuntu Booting

Problem:

It takes too much to start Ubuntu 14.04.2 LTS 32-bit (7 minutes after the Grub screen).

Problem description

1. I turn on the PC
2. 1 minute after the Grub screen appears
3. Once selected Ubuntu as the operative system it starts the process of loading the OS.
4. 7 minutes later, the login screen of Ubuntu appears.
5. Once Ubuntu starts, everything works 100%

Computer description

• Laptop ACER Aspire 5542-5770
• CPU: AMD Turion II X2 M500 – 2.2GHz, 1MB L2 Cache
• Video card: ATI Radeon HD 4200 Graphics up to 1919 MB HyperMemory
• RAM: 4 Gb
• Hard drive: 320 Gb (/dev/sdb)
• Ubuntu is not installed in the laptop hard drive, it's installed in a portable hard drive connected through USB.

External hard drive Toshiba 500 Gb (/dev/sda)

• /dev/sda1 – ext2 – /boot – 2 Gb
• /dev/sda2 – ext4 – / – 50 Gb
• /dev/sda3 – extended
  • /dev/sda5 – linux-swap – 2 Gb
  • /dev/sda6 – ext4 – /home – 172 Gb
• Free – 240 Gb

Records from boot are useless. All the records start 30 seconds before Ubuntu starts, meaning that they start 6 minutes and 30 seconds after the Grub screen.

Solutions tested (It didn't work)

• /etc/default/grub: I tried modifying this line: GRUB_CMDLINE_LINUX_DEFAULT=""
• I tried using all this parameters: splash – quiet – noapic – nolapic – acpi=noirq

None of this makes a change at all.

I am also sending all the reports, and it must be taken into account that I turned on the computer at 22:00.

Logs on pastebin.org or on drive.google.com (original link)

Bootchart Image on imgur.com or on drive.google.com (original link)

Edit

It is not a problem of USB speed. In another computer it tooks less than one minute to start, so the problem is my Laptop.