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SSD booting slower than rotary HD? You might have a ghost disk reference

Posted by admin |

I changed to an SSD, re-installed Ubuntu 16.04LTS and my boot times slowed to a crawl. Turned out the installation script had put in an imaginary swap drive in  my /etc/fstab. Systemd then waited for it, for a minute or so while booting. In the logs (which you reach with journalctl on systemd) it looked something like this:

sep 15 23:25:33 hostname NetworkManager[2733]: <info>  [1473974733.3738] WWAN hardware radio set enabled
sep 15 23:26:09 hostname systemd[1]: Starting Stop ureadahead data collection...

Or like this:

sep 16 00:54:40 hostname kernel: nouveau 0000:01:00.0: DRM: suspending kernel object tree...
sep 16 00:56:03 hostname systemd[1]: dev-disk-by\x2duuid-7553704f\x2d1ffd\x2d490b\x2db12b\x2d5174b3464643.device: Job dev-disk-by\x2duuid-7553704f\x2d1ffd\x2d490b\x2db12b
sep 16 00:56:03 hostname systemd[1]: Timed out waiting for device dev-disk-by\x2duuid-7553704f\x2d1ffd\x2d490b\x2db12b\x2d5174b3464643.device.

In the second one I could use gparted to find out what disk ids were and weren't present on my system. The comments in fstab indicated the wrong one, that is the existing swap was preceded by the comment:

# swap was on /dev/sdb2 during installation

While that one is on /dev/sda5 actually, and the non-existing one was marked up with:

# swap was on /dev/sda5 during installation


Sep 16, 2016 09:25

I built some password boosters with Arduino

Posted by admin |

One Arduino micro clone from Kjell & Company and one Pololu  A-Star 32U4 Micro  (the small one) from Lawicel.

Sep 15, 2016 11:25

Making a USB compatible casing for a teensy or Arduino micro

Posted by admin |

Trying to figure out how to make a casing for these small USB-enabled boards. One way would be to encase it in some clear resin, such as in epoxy or polyurethane or silicone. Another is to use heat shrink tubing. Here is what I have learned so far:

Heat shrink tubing works fine. The little fellow below is wrapped in three layers of it, first a red tube fitted from the back, then two strands of black tubing fitted from the sides, and finally black tubing fitted from the back again.

I've read that:

  • Silicone may emit acids as it is curing. This may not be good for electronics
  • Epoxies may change volume as it is curing and put permanent massive stress on components

I'll post more as I figure things out.

Sep 14, 2016 02:05

Using a different sleep (suspend) and hibernate on Ubuntu 16.04

Posted by admin |

Suddenly suspend and hibernate stopped working on,  my laptop which has a self encrypted SSD disk. Probably it isdue to some graphics cards shenaningans and not the SSD, but here goes:


sudo apt-get install uswsusp

For sleep, issue:

sudo s2ram -f -a 1

For hibernate issue:

sudo s2disk

Haven't manged to get it working with the Gnome power manager, so I use separate icons for the above commands.

linux - LinuxMint15: Suspend to RAM not working - Unix & Linux Stack Exchange

Uswsusp - ArchWiki

Ubuntu Manpage: uswsusp.conf - Config file for the s2disk program



Sep 14, 2016 01:55

How to switch between Intel & Nvidia graphics cards on Ubuntu

Posted by admin |

Warning: This borked my machine, I had to boot into recovery mode, drop into a root shell and issue:

mount -o remount, rw / order to remount the file system in read-write mode.

Then I did

apt-get purge nvidia*

Anyways, here how i borked up:

This is the important invocation:


Read more: Link - How To Switch Between Intel and Nvidia Graphics Card on Ubuntu

Sep 13, 2016 12:20