Saturday, 17 September 2011

Insulation part 1

We want to get the house insulated and energy-sorted.  Im discovering its not easy and straightforward to retrofit an 1860s victorian  terrace.

There are a number of different projects that need tackling.
This is one - sorting out an area at the back of the house - its a cold corner, I  think for several reasons - the solid wall is an external one - the neighbours' room stops short of our probably edwardian extension, there isn't a radiator really adjacent, and there is a very nice Velux window, which lets in a lot of light during daylight hours and is double glazed, but i bet there is some heat loss through it.

There has been damp coming through  - I think from a bush that was growing ito the brickwork, but the wall has been stripped for a while and  seems to be dry now.

Part of the wall has a cupboard along it , so its a relatively small area that is exposed. Ceiling to floor is approx 290 cm and the length of wall is approx 190cm. We thought studs and sheeps wool and then plasterboard is overkill. So its a board of some sort. And I've read that  damp can be a problem, as any moisture  condenses on the cold surface of the wall . So the  joins in the board etc are taped. But what about at the top and the bottom ? Does it mean that it will only really work well if its fully insulated and sealed at the top and the bottom to prevent ingress of water vapour laden air  -   Ive therefore got to remove the skirting board, and the original moulding ( it may eventually all be going - but that doesn't solve *this* problem.). The room isn't used a lot at the moment - so it shouldn't be a problem ( should it ? )

Ive  gone to google ( as you do ) . Heres a forum discussion that includes stuff  about  calculating the dew point of a wall. if I can calculate the dew point, I could show that it may not be a problem and another forum that highlights the problem of excessive condensation and it having nowhere to go

Ive not yet found the 2007  iso standard but there is this powerpoint about condensation (surface and interstitial) . its got 2 pictures -  this of internal insulation (which hasn't got vapour barrier)

and this of a timber-framed wall ( it looks like a stud with insulation between, and plasterboard on top ) - but this has got a vapour barrier .

I think what I need is the Glaser method of calculating the dewpoint.

Some of the insulation boards that you can buy come with  an integral vapour barrier. But will end up not letting  moisture out ?

or are we back to thinking  about studs and lambswool as the insulation , because that will breathe , or what i have seen listed as 10mm flexible liner  - it looks like its 'polystyrene wallpaper'

Friday, 9 September 2011

Javascript Associative Arrays

I've spent some time  looking into Javascript associative arrays.  But javascript doesn't have associative arrays. it has objects that can have values that can be accessed in a similar way to associative arrays in perl and PHP. Im no expert but heres how I created a multidimensional javascript array  from a PHP array .
The PHP  array has 4 levels  , that are read from a database .

So I've  read data from the database and  created a multidimensional PHP associative array


so the php writes some javascript

Thursday, 1 September 2011

backing up - or not.

ive got a good system running for backing up windows machines .
I thought Id sort out the backing up of my  linux machine as well.
So i thought id do the same thing
  • create a shared folder on the remote system
  • make it accessible to the computer I want to back up . 
  • run rsnapshot and Im done 
But Im not done  .Both systems run linux , so it would be a nfs share.

on the server
root@server:/home/backup/mars/hourly.0/mars# ls -la /home/backup/ | grep ma
drwxrwxrwx  4 mars    users     4096 2011-09-01 14:27 mar
 on the client
 mar@mar-desktop:/mnt$ mount | grep nfs on /mnt/marbackup type nfs 
 and i get this
 mars@mars-desktop:/mnt$ sudo rsnapshot  -c /etc/rsnapshot.conf  hourly
 require Lchown
 Lchown module loaded successfully
 Setting locale to POSIX "C"
 echo 6806 > /var/run/
 mkdir -m 0755 -p /mnt/marsbackup/hourly.0/
 /usr/bin/rsync -avx --delete --numeric-ids --relative --delete-excluded \
     --temp-dir=/tmp --exclude=*iso --exclude=Dropbox/* --exclude=Ubuntu* \
     --exclude=.* --exclude=Downloads/* /home/mars \
 sending incremental file list
 created directory /mnt/marbackup/hourly.0/mars
 rsync: chown "/mnt/marbackup/hourly.0/mar/home" failed: Remote I/O 
 error (121)
 rsync: chown "/mnt/marbackup/hourly.0/mar/home/mars" failed: Remote 
 I/O error (121)
 /home/mars/A4L Flyer (2up, 2x A5).ott
 /home/mars/Agenda_Committee Net Meeting_17_July_2011.pdf
 on the server its this
 root@server:/home/backup/mar/hourly.0/mars/home/mar# ls -la
 total 1956
 drwx------ 21 nobody nogroup   4096 2011-09-01 14:38 .
 drwx------  3 nobody nogroup   4096 2011-06-04 15:27 ..
 -rw-------  1 nobody nogroup 113146 2011-08-26 13:40 a4flyer.jpg
 -rw-------  1 nobody nogroup   9955 2011-08-26 12:16 A4L Flyer (2up, 2x  A5).ott
 -rw-------  1 nobody nogroup  71243 2011-07-17 20:10 Agenda_Committee 
 Net Meeting_17_July_2011.pdf
 I can access the backed up stuff from the server , as root .
 but when i come to run the backup again
 it fails
 mars@mars-desktop:/mnt$ sudo rsnapshot  -c /etc/rsnapshot.conf  hourly
 require Lchown
 Lchown module loaded successfully
 Setting locale to POSIX "C"
 echo 6918 > /var/run/
 native_cp_al("/mnt/marbackup/hourly.0", "/mnt/marbackup/hourly.1")
 mkdir("/mnt/marbackup/hourly.1", 0755)
 safe_chown(4294967294, 4294967294, "/mnt/marbackup/hourly.1")
 rsnapshot encountered an error! The program was invoked with these options:
 /usr/bin/rsnapshot -c /etc/rsnapshot.conf hourly
 ERROR: Warning! Could not safe_chown(4294967294, 4294967294, 
 ERROR: Error! cp_al("/mnt/marbackup/hourly.0/", 
 /usr/bin/logger -i -p user.err -t rsnapshot /usr/bin/rsnapshot -c \
     /etc/rsnapshot.conf hourly: ERROR: Error! \
     cp_al("/mnt/marbackup/hourly.0/", "/mnt/marbackup/hourly.1/")
 rm -f /var/run/
the problem is the root_squash option in nfs . The defautl is root_squash - ie  stuff transferred across is owned by nobody, rather thatn user that can do stuff. 
So i changed the mount options to 
rw,no_root_squash, and added the same user (mar) to the server . 
But still not fixed.I think the UIDs have to be the same as well 
And the ssh option in rsnapshot looks like its a pull backup option rather than push. 
Hmmm . I'l have to have think about this