Air Conditioning and asthma

As climate change increases outdoor temperatures, air conditioning will more often be used to maintain comfortable indoor conditions. Climate change is expected to stimulate installation of air conditioning in some buildings and locations that would otherwise not need air conditioning. In the 2011 American Housing Survey [109], 64% of housing units had central air conditioning and 21% of housing units had one or more room air conditioning units, so at least 15% of existing US houses had no air conditioning. Also, where air conditioning is already present, operation times will increase. The increased use of air conditioning driven by climate change is expected to affect health both positively and negatively. In some locations and buildings, existing air conditioning systems may become unable to maintain comfortable temperatures as the climate warms [110].

Air conditioning can attenuate high indoor air temperatures during heat waves. Increased availability of air conditioning, stimulated by climate change, would be expected to diminish the increases in adverse health effects resulting from the increases in frequency and duration of heat waves. Ostro et al. [111] found that the increase in respiratory hospitalizations with high outdoor temperature was approximately halved among people who reported ownership or use of air conditioning, after controlling for income. The associated long-term health benefit will depend on extent of increased air conditioner availability in homes, which is not known.

When air conditioning is employed in naturally-ventilated buildings such as most homes, windows are more often maintained closed; consequently, rates of building ventilation with outdoor air are reduced. By keeping windows closed in naturally-ventilated buildings, indoor air concentrations of some outdoor air pollutants, particularly particles and ozone, from outdoor air are diminished. At the same time, indoor air concentrations of pollutants emitted from indoor sources will increase in naturally-ventilated buildings when air conditioning is employed due to the closing of windows and reduction in outdoor air ventilation. Some new and remodeled homes and most commercial and institutional buildings provide outdoor air ventilation mechanically using fans. In these buildings, changes in use of air conditioning will have a smaller impact on rates of outdoor air ventilation. Continue reading Air Conditioning and asthma

Thunderbird and bad date format

Basically the date format in Thunderbird follows the system locale – in a terminal type ‘locale’ and the LANG entry should be something like en_GB – if it’s en_US, that’s why it’s displaying the date in the bizarre US format which is MM/DD/YYYY rather than DD/MM/YYYY

To rectify this problem:

1. locale -a
2. vim /etc/locale.gen
3. uncomment:
en_GB.UTF-8 UTF-8
4. comment out:
en_US.UTF-8 UTF-8
5. locale-gen
6. localedef --list-archive OR localectl list-locales
7. vim /etc/locale.conf
LANG=en_US.UTF-8

To make locale changes immediate:

8. unset LANG
9. source /etc/profile.d/locale.sh

Migrating to a larger SSD disk

I have upgraded to a larger SSD disk, I moved from 500GB to 1TB.

I think the best option is to connect 2 disks to the SATA3 connectors and use dd to clone the whole disk from a smaller to the larger one. This is the fastest way and it took only 17 minutes to clone 500GB with over 500MB/s transfer rates.

lsblk
dd if=/dev/old of=/dev/new bs=1M conv=noerror,sync status=progress

then use GParted to make any changes to partition layout.

This tool is very easy to use and does the job. After you remove partitions you don’t need and move things around you end up with a bunch of unallocated disk space you would like to merge with your existing home partition. In my case this partition is encrypted. I have resized this partition using GParted. After that you have to decrypt the partition to then be able to resize

cryptsetup luksOpen /dev/sdx homecrypt
cryptsetup resize homecrypt
e2fsck -f /dev/mapper/homecrypt
resize2fs -p /dev/mapper/homecrypt

If the partition layout has changed much you want to update fstab and Grub

Windows wants to format your external hard drive?

It looks like filesystem on your external hard drive is having some issues, but most often these issues are not impacting the whole disk partition but it’s to do with some individual files that may be corrupt.

Windows asking to format the hard drive is way too much.

Instead of following Windows please run the below command as administrator from Windows CLI:

chkdsk E: /f

where E: is the letter of the affected hard drive partition.

Windows 7 N and HTC phone

I was unable to connect my HTC phone to Windows 7, it was not detecting it properly.
It was showing it as “Android Phone” but after multiple attempts I had no success with driver installation, no access to photos. Installing HTC Sync Manager did not help either.
It turned out that Windows 7 N which is a separate Windows 7 release for European Union is lacking Media Pack which contains necessary bits and pieces.
You have to download Media Pack from Microsoft website, install then restart your system then all should work fine.

Disable touchscreen in Windows 7 and Linux

In Windows please disable one of the HID Devices in Device Manager, if this does not work try USB device listed in the same Device Manager HID container.

In Linux edit the “/usr/share/X11/xorg.conf.d/10-evdev.conf” file.
You edit the touchscreen section in 10-evdev.conf file is the last section.
It will have this identifier in the section – Identifier “evdev touchscreen catchall” – the identifier seems to be the 2nd line in all the sections.
Just add in this line – Option “Ignore” “on” as the last line before “End Section”

mount –bind vs symbolic link

With mount –bind, a directory tree exists in two (or more) places in the directory hierarchy. This can cause a number of problems. Backups and other file copies will pick all copies. It becomes difficult to specify that you want to copy a filesystem: you’ll end up copying the bind-mounted files twice. Searches with find, grep -r, locate, etc., will traverse all the copies, and so on.

You will not gain any “increased functionality and compatibility” with bind mounts. They look like any other directory, which most of the time is not desirable behaviour. For example, Samba exposes symbolic links as directories by default; there is nothing to gain with using a bind mount. On the other hand, bind mounts can be useful to expose directory hierarchies over NFS.

You won’t have any performance issues with bind mounts. What you’ll have is administration headaches. Bind mounts have their uses, such as making a directory tree accessible from a chroot, or exposing a directory hidden by a mount point (this is usually a transient use while a directory structure is being remodelled). Don’t use them if you don’t have a need.

Only root can manipulate bind mounts. They can’t be moved by ordinary means; they lock their location and the ancestor directories.

Generally speaking, if you pass a symbolic link to a command, the command acts on the link itself if it operates on files, and on the target of the link if it operates on file contents. This goes for directories too. This is usually the right thing. Some commands have options to treat symbolic links differently, for example ls -L, cp -d, rsync -l. Whatever you’re trying to do, it’s far more likely that symlinks are the right tool, than bind mounts being the right tool.

it’s worth noting that some utilities might consider a bind-mounted directory to be a separate file system. This may have performance or functionality implications if the program can no longer assume that the same inode number refers to the same file (which it doesn’t, if they are on different file systems), a move cannot be optimized as link-at-target-then-unlink-source, etc.

Author: Gilles

Time zones

Dirty script to show times in different places in the world

echo -n -e "World Times:\n\tTokyo\t\t"; TZ=":Asia/Tokyo" date | cut -d " " -f4; echo -n -e "\tShanghai\t"; TZ=":Asia/Shanghai" date | cut -d" " -f4;echo -n -e "\tMoscow\t\t"; TZ=":Europe/Moscow" date | cut -d" " -f4;echo -n -e "\tRome\t\t"; TZ=":Europe/Rome" date | cut -d" " -f4;echo -n -e "\tLondon\t\t"; TZ=":Europe/London" date | cut -d" " -f4;echo -n -e "\tNew York\t"; TZ=":America/New_York" date | cut -d" " -f4;echo -n -e "\tLos Angeles\t"; TZ=":America/Los_Angeles" date | cut -d" " -f4

find your preferred places in /usr/share/zoneinfo
then place the script in your .bashrc

Swap

Quick way to setup swap

fallocate -l 4G /swapfile
ls -lh /swapfile
sudo chmod 600 /swapfile
ls -lh /swapfile
mkswap /swapfile
swapon /swapfile
free -m

vim /etc/fstab
At the bottom of the file, you need to add a line that will tell the operating system to automatically use the file you created:
/swapfile none swap sw 0 0

Windows 7: regaining disk space

net stop wuauserv
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
net start wuauserv
rd /s/q %systemroot%\SoftwareDistribution.old

DISM.exe /online /Cleanup-Image /spsuperseded

bear in mind that above command is super-case-sensitive
sfc /scannow

Unfortunately in Windows 7 you cannot get rid off update packages in WINSXS folder (this can reach 12GB). You can clear it up in Windows 8.1 and later.

Security clearance in UK

Types of national security clearance

There are four main types of Security Clearance – Baseline, Counter Terrorist, Security Check and Developed Vetting. Below is an outline of each type of Security Clearance, along with information on the process, how long it takes, and the types of IT jobs it applies to.

The important thing to remember is that Security Clearance checks are conducted in line with a specific IT job role, and need to be requested by a company not an individual. So while Security Clearance may require some time and paperwork, if successful it will lead to a new IT job – as well as career rewards such as a good salary, role security and plenty of opportunity.

Baseline Security Clearance

There are two types of check in this category: Baseline Personnel Security Standard (BPSS) (Formally Basic Check) and Enhanced Baseline Standard (EBS) (formerly Enhanced Basic Check or Basic Check +). A BPSS or EBS aims to provide an appropriate level of assurance as to the trustworthiness, integrity, and probable reliability of prospective employees.

What is BPSS?
BPSS is an entry level security check, and will take one or two days to complete. Not technically a security clearance, it uses the Police National Computer (PNC) to make sure a candidate has no convictions. The check returns evidence of any current criminal record and un-spent convictions under the Rehabilitation of Offenders Act 1974.

A BPSS acts as a pre-employment check, signaling good recruitment and employment practice in general. The check is carried out by screening identity documents and references. Continue reading Security clearance in UK

VirtualBox and networking between guests

For this to happen you have to enable a secondary network adapter that is set as Internal Network (make sure you assign both guests to the same Internal Network, default is “intnet”)
The next step is to enable DHCP server on that network by this command:
VBoxManage dhcpserver add –netname intnet –ip 10.0.0.100 –netmask 255.255.255.0 –lowerip 10.0.0.101 –upperip 10.0.0.150 –enable

whatever you do or fix please test it afterwards, better however do not fix things that work, wait until they break otherwise feel the wrath of dummy users.