Category: computing

General computing topics covering everything I deal with or am interested in.

Posted on
by

INTRODUCTION

Enough was enough. I rocked and rolled along with one mainstream distribution after another, since I started using GNU/Linux in 2000. It was time for something else. Something that wasn’t trying to be everything.

Even I was slightly surprised then that, knowing so little about it, I chose Slackware Linux as my next distribution.

Here are some rough-and-ready notes from my installation, in case they’re of help to anyone else.

INSTALLATION

To install on an encrypted drive, I followed Juan Valencia’s blog:

http://www.jveweb.net/en/archives/2010/10/installing-slackware-in-an-encrypted-lvm.html

Apart from the natural modifications expected, i.e. kernel versions, the instructions were completely sound and the installation proceeded without issue.

INITRD KEYMAP

One LILO was installed, and the system rebooted, I had two issues:

  1. The USB devices attached to my ThinkPad’s docking station weren’t activating at boot time
  2. The keymap of the initial ram disk was set to US, so to decrypt my drive I had to observe the alternative placement of certain characters… 😉

To resolve these issues, I found the “IT Debris” blog (amusingly sub-titled: “Nothing lasts, nothing is finished, nothing is perfect”):

http://blog.beulink.org/slackware-initrd-luks-usb-keyboard/

To the command line (mkinitrd -c -k 3.2.7 -f ext4 -r /dev/vgl01/lvroot -m usb-storage:ehci-hcd:usbhid:jbd2:mbcache:ext4 -C /dev/sda2 -L -u -o /boot/initrd.gz) I added the flag “-l uk”, which loaded the UK keymap by default into the initial ramdisk.

Not forgetting to run lilo afterwards!

LILO’S KEYMAP

LILO’s keymap was also set to US. I decided to take a look at this. While the documentation is pretty comprehensive, the instructions for this particular issue were met with a slight problem – the file locations and names had changed in the 13 years since the documentation was written.

keytab-lilo is the recommended tool for updating LILO’s keyboard mapping.

keytab-lilo expects a US map and the other map (in your language, that you want to use) in order to create a mapping between them.

According to the docs, as referenced in /usr/share/doc/LILO…/doc/README’s web link, keytab-lilo expected keyboard mappigns in /usr/lib/kbd. This directoty doesn’t exist, so I did this:

mkdir usr/lib/kbd mkdir /usr/lib/kbd/keytables

loadkeys uk

cd usr/lib/kbd/keytables

cp /usr/share/kbd/keymaps/i386/qwerty/uk.map.gz . cp /usr/share/kbd/keymaps/i386/qwerty/us.map.gz . gunzip uk.map.gz gunzip us.map.gz

mv us.map us.kmap mv uk.map uk.kmap

keytab-lilo uk > /boot/uk.ktl

.. FINALLY, edit /etc/lilo.conf in your favourite editor:

emacs -nw /etc/lilo.conf

boot = /dev/sda keytable = /boot/uk.ktl

NOTE: the remapping doesn’t seem perfect. The hash (“pound” in en_US) symbol (#) is mapped to two keys and the UK pound (£) symbol is not mapped to number 3 at all, but in the main this is a usable UK mapping for me.

AND.. THE SYSTEM KEYMAP!

Edit /etc/profile.d/lang.sh, adjusting from en_US to en_GB

POST-INSTALL STUFF

After this, there were a couple of issues which I wanted to resolve. When using Ubuntu, I recall there was an issue with using a ThinkPad T420 (my machine) and possibly other ThinkPads with audio output via the docking station‘s analogue port. The issue was also addressed in a Ubuntu forum post.

I created /etc/modprobe.d/t420.conf and added the following:

options snd-hda-intel model=thinkpad

options iwlcore led_mode=1

.. then rebooted. Perfect – audio came up as expected. The flashing LED still appears to be flashing, though, so this requires further investigation.

INSTALL GOOGLE CHROME

http://web.archive.org/web/20150815075708/http://infinityperl.org/post/2009/12/09/How-to-install-Google-Chrome-on-Slackware-13.html

(+ hangouts plugin): http://slackblogs.blogspot.co.uk/2010/08/videovoice-chat-works-in-slackware.html

TERMINAL – modifying the prompt

A long trip arouind the documentation and understanding how bash is invoked made me realise that the easiest thing to do is go into XFCE’s Terminal preferences, and tick the box that says “Run Command as login shell”. Then I get my nice prompt with my login, hostname and path instead of just “sh-4.20$”.

PSEUDO SUMMARY

These are my first steps at installing and configuring Slackware Linux. So far, so good. And not a single crash, which is what I expect from a sensible GNU/Linux distribution.

Posted on
by

If you have a curious bent – and you bought a Chromebook thinking it would be the answer to all problems, then chances are you probably gave up on that notion fairly quickly and installed a variant of GNU/Linux on it.

If so, well done. Thankfully, Daniel Berrange – a Red Hat fellow and Fedora users, posted some instructions on how to get Fedora 18 (Spherical Cow) installed on a Samsung series 3 (XE303C12) Chromebook. This is the route I decided to take, having been a Fedora user for many years. But I digress.

If you have GNU/Linux installed on a Series 3 Chromebook, you may want to remap those Google-inspired function keys that run across the top. You know, those keys with the arrows, reload, window-size/position, brightness and volume icons… Yeah. Actually, they’re function keys: F1 to F10.

A good read for how to identify what each key is can be found here, on this askubuntu post which details the xev command.  xev displays the numeric keycode of the keyboard key (!) you just pressed.

Keys F1-F10 use the following keycodes:

KeyKeycodeEquivalent
Back67F1
Forward68F2
Reload69F3
Resize70F4
Stacking71F5
Bright down72F6
Bright up73F7
Mute74F8
Sound down75F9
Sound up76F10
Using xev, you can remap the function keys to something more appropriate to your environment.

To remap these keys, we now need to identify what extended functionality the XF86 multimedia keyset provides.

A reference table is available is available on linux questions.

Posted on
by
Spot the difference!
Given fair test conditions, everyone knows wired network connections are faster than wireless, right?  How about when your wired connection crawls along at 1/5 of the speed of your wireless connection?  What’s happening?Below are two CAT 5e Ethernet cables, of the type you’d typically use to connect a router to a modem, or perhaps your PC directly into your router instead of using WiFi.  You might connect up other network-capable devices in your home too, such as a PVR/HDR, Blu-ray player and even your TV.  In doing so, you may pick up an old Cat 5 cable “you had spare” to do the job.

Beware, that not all Cat5e is the same!
If you look closely below, you’ll see that the lower, grey cable is type 568A, whereas the upper, black cable is568B.  Ethernet cables come as UTP or STP (Unshielded or Shielded Twisted Pair), meaning that each pair of conductors (wires) inside the outer sheathing are twisted together.  This helps cancel noise and improve transmission.

The difference between A and B is in the way these twisted pairs are paired up.  If your router has N-Way negotiation on its network connections, it should be able to work around using the two different types of cable.  But on my router, with N-Way negotiation, this didn’t appear to be the case.

Testing this using speedtest.net with cable type A, I got a paltry 5Mb/s down and 4Mb/s up.  Over wireless, I got 20Mb/s down and 17Mb/up.  It turned out that my router can’t handle type A cables very well.  Using a type B, I got 44Mb/s down and 18Mb/s up.  More like it!

So the next time your network is running slowly, check your cabling.  Even if it’s a well-known brand (my type Acable is a Belkin Cat5e), it may be causing a drop in performance which is easily, and cheaply, corrected.
H/t +Bob Beattie 
#networking   #speedtest   #cat5e  

Show less

1

Posted on
by

I recently came across the dreaded owncloud login loop. This surprised
me a little, as I hadn’t performed a software upgrade or otherwise
changed any configuration parameters for a while.

So why the change?

One lesson I have learned long and hard through developing web sites and
testing, is that there are two components which are equally
important: program code and data. Never assume there is
something wrong with your code; your live data (or test data) could be
equally at fault, causing your application to slip up.

In the case of ownCloud, I found that my hosting environment had reached
its quota. Although ownCloud could create session files in /tmp, it
couldn’t write data to them. Perhaps the code should have handled this
more gracefully, but it’s safe to assume that a cloud environment
has hard disk space in order to save its files. That’s what it’s
there for, after all.

So here’s a quick, work-in-progress checklist to ensure your ownCloud installation has the
best chance of working correctly:

  • PHP Sessions should be enabled
  • session.save_path in php.ini should point to a valid (writable)
    filesystem location
  • Storage space on hosting environment should be ample

More to follow when I have further issues..!

Posted on
by

This wasn’t the droid I was looking for

Motorola Razr HD smartphone rear cover
Good finish… bad start!

I was so happy recently to unpack my brand new Motorola RAZR HD.  It’s a lovely device. Wonderfully built, with a 4.7 inch 720p screen, replete with Gorilla Glass, and backed by a rubberized kevlar weave.  The aluminium strip separating the two, running around the edge of the phone, provides a premium feel.

Or, at least, this is what I was led to believe from various reviews.

In reality, what you have is a beautiful brick – with good battery life. Android 4.1.2, the operating system shipped with the phone and modified by Google/Motorola Mobility, to ensure the phone is quite unusable, provides an amazing experience – if you connect up your Google account.

The Empire Strikes Back

What happens if you don’t have a Google account, or if you’re unprepared to create one?

What happens is that the software on the phone may refuse to play nicely with other software you choose to install. Here are some examples of this obnoxiusness:

  • Phone set-up
    • Before even seeing the home-screen, you are prompted to log into your Google account – or create a new one. You decline.
    • You are reassured that it’s a really good idea to create a Google account, otherwise you’ll “miss out”.
    • Resolutely, you continue. You get to the home screen. Then you want to install something from the Android Market (sorry, “Google Play”). You now cannot avoid creating or using a Google account.
  • Contacts
    • The phone is still behaving as though you are not fully connected to Google. Therefore, your data storage is predominatly on the phone only.
    • However, you might want to check this in ‘Accounts and Sync’ (which we’ll get on to in a sec)
    • You have the option of synchronising your data off elsewhere, away from Google’s servers. The CardDAV Sync software on Google Play provides the vehicle for doing this*. You download and install it, set up the sync with your CardDAV server, and sync away.
    • You might find that some of the software from Google updates on your phone during this time, now that it has access to the market.
    • All good… but, you soon come to realise that you cannot add new contacts to your chosen sync location. Take the scenario where you receive an SMS from an unknown number. You try to add the contact from the SMS, and can only do so to local storage.
    • Worse still, your only option to alleviate this – the only sync location you can add contacts to is – that’s right, a/your Google account.
    • If you delete your Google account on the phone, you then find that you cannot sync your contacts anywhere, because you cannot specify a default Contacts Store in the Contacts app.
  • Calendar
    • The same is broadly true of the Calendar. If you are not sync’ed with a Google account, the only calendar you can use on the phone is the built-in phone calendar. You cannot use another, third-party calendar as the default store or synchronisation copy.
    • If you create calendar events on your phone without a Google account, even though you have other accounts which provide full calendar syncing capability, you will still be creating an event on the local calendar that has no synchronisation counterpart
    • During the course of writing this article, strangely the option appeared in my calendar to utilise alternative calendars when creating an event. We shall see if this persists..
  • Accounts & Sync
      • This section has become a total mess in Jelly Bean – especially in Motorola’s implementation.
      • You start at the home screen: swipe down (or across from left-to-right) to get to Settings (the cog symbol)
      • In Settings, you scroll down the list to the Accounts section. Hit CalDAV or CardDAV.
      • You are then taken to the respective app’s account information with a link to Edit account settings. Let’s hit that.
      • The screen scrolls again to another black screen showing the same account, the settings of which you want to change. Yet another tap on this…
      • .. and hey presto, you’re finally in! Here you make changes and then hit the back key.
      • … and then hit the back key…
      • … and then hit the back key…
      • and then you’re at Settings again, so..
      • … you then hit the back key…
      • …and you’re out!  (seriously, was this actually DESIGNED?!)
    • Going the other way into the apps settings (sorry if this is too painful for you) you first hit the Apps shortcut:
    • Hit the CalDAV or CardDAV icon
    • You then have the option: “Add account”, or “Go to accounts & sync”. Let’s say I want to edit an account, I’d choose “go to accounts and sync”..right? I tap it.
    • Oh, then there’s a pop-up style interface with ALL of your sync accounts. So I have to find my CalDAV app in the sync accounts list and tap on it…
    • Then I can see the calendar account I want to sync.  But how do I edit it? When i tap on it, it synchronises! Ahh, wait, there’s a menu/settings button (the one with three squares). I tap on that…
    • … and get the options “Sync now” or “Remove account”.
    • So, let’s get this right: to EDIT my app’s data, I go to Settings > Accounts & Sync (not to the app). And when I want to SYNC the account or DELETE it, I go to the app! That’s logical!

    In summary…

    Android is an open source ecosystem that encourages vendors to produce lock-in experiences which are frustrating, dysfunctional and unintuitive.

    And to think I was pro-android this time last week.  I suppose I still have the t-shirt.  The retailer will soon have the phone back, though.

    bootnote

    *CalDAV sync and CardDAV sync are both great pieces of software that fully get my support (and have done, in the financial sense).  I use them here as examples of good apps which are potentially made almost impossible to use by the restrictions imposed by Android OEMs.

    Posted on
    by

    Quite simply, I am very happy to be back in Emacs-land.

    There I was, thinking that the web-based task managers, to-do lists, etc
    were “all that”. Well, ok, I do feel that some are pretty good, as you can tell from
    my tag cloud on this blog. But nothing ever felt like it was native to
    me, this keyboard and this computer.

    I wanted to put tasks on a computer to Screenshot - 100413 - 10:55:20make them easier to manage.  Putting them on a web site didn’t do that, and I don’t think it ever
    really will for me. So I’m back in the saddle with orgmode and boy, am I loving this again. It’s amazing how the keystrokes just come back to
    you.

    Here’s my list of software in Emacs (at  present):

    • mu4e, for E-mail
    • orgmode, for task/calendar management
      — mobileorg, for portability
    • weblogger, for blogging (duh)

    For coding, I’m also using:

    .. plus some other fontification and syntax colouring plugins.

    Truly forgot what a joy it is to use this environment, although it does
    take a little work setting up.

    Posted on
    by

    A simple one, this. Firstly, get to where rhythmbox stores its data:

    # cd ~/.local/share/rhythmbox

    Then, do this:

    # grep podcast-feed rhythmdb.xml -A 5 | grep location | sed -e 's/<location>//' | sed -e 's/<\/location>//'

    You should end up with a list of URLs which your podcast feeds are served from.

    Posted on
    by

    This is a blog post for personal interest and probably not of much amusement to others.

    My work machine has a fresh install of the (soon-to-be released) Debian version 7 (codename “Wheezy”). There are a couple of modifications I’ve had to make to the installed software to get things working as desired.

    Firstly, I’ve read really good things about mu4e – the “maildir-utils for emacs” email client.  (Just for clarity, the author of maildir-utils has abbreviated its name to mu.)  mu4e provides an interface to your email in emacs which is fast and efficient.  I like things that are fast and efficient.

    I installed debian’s standard mu and mu4e packages, but found that mu (the wheezy-based package) was not indexing all of my email. Firing up mu4e within emacs then trying to browse the ~/Maildir/INBOX – and being told there were no messages – raised some suspicions!  So I removed that package and installed from source instead and, now, indexing works much better.

    how to do this

    Basically, it’s pretty simple.  Just:

    # apt-get remove mu4e

    This will replace maildir-utils (0.9.8) and mu4e.  Then download the mu-0.9.9.5 source (list of mu releases) and follow compilation and installation instructions from its install page.

    On Debian, this will result in you installing mu and mu4e to /usr/local/share instead of the default installation point, /usr/share.  To enable the use of /usr/local/share/emacs/site-packages/mu4e/ from within your standard emacs23 install, just create a symlink pointing to it from /usr/share/emacs/site-packages/ :

    # ln -s /usr/local/share/emacs/site-packages/mu4e/ .

    The software replacements are:

    •  with mu (0.9.9.5) from the  package

    other modifications

    (Edit) I also installed gnu tramp for Emacs from source, but the reasons why I originally did this now escape me, as tramp has been part of Emacs for a while.

    unrelated issues

    I have found a worrisome issue in wheezy.  When I attach an eSATA drive to my ThinkPad (T420) and copy lots of data – e.g. GBs of photos – to my ~/Pictures, I get some kind of kernel panic/X error.  I’m still investigating this at present.

    I will attempt to keep this list updated as I continue getting this set-up just as I want it 🙂

    [ EDIT 10 April 2012 10:00 ]

    Grabbing the currently stable, newest kernel source (ver 3.8.6) and compiling it in the debian way has seemingly fixed this crashing/locking issue.

    Posted on
    by

    Let’s be clear:  I am a stubborn git.  I’m the first to admit it.  To the dismay or, perhaps, bemusement of my friends, I struggle with product concepts such as the iPhone, iTunes, Amazon Kindle, eBooks in general, Facebook and Skype.

    My friends tell me it’s because I don’t like to conform with the “normal” things that everyone else does.  Things like broadcasting my whereabouts and the company I keep at all times in my life, wherever I am.  Apparently, disagreeing with the background, terms of service, patenting practices and Digital Restrictions Management (DRM) of various “social media” service providers is anti-social and rebellious. 

    It’s a curious thing to be a digital pariah.

    What my friends don’t understand is that I don’t restrict my opinions to Apple, Facebook Inc., Microsoft and Amazon.  It’s just that they’re the companies my friends use, so to relate to them I cite them as examples.  I feel exactly the same way towards some of Google’s services and products, although I do have slightly more faith in Google than any of the above named alternatives.  They do more good, in my opinion.  And, with Google, at least you have confidence in being able to delete anything you create.

    My main objections to these services & products, then, are:

    • privacy: I do not wish to be “guilty by association” on any social network.  Being tagged without my permission, and/or the attempt of tagging me (whether I disallow or permit the tag – or ignore the attempt to tag) is not acceptable.  It is especially unacceptable when I have no faith that the service provider will protect my interests as a private individual and law-abiding citizen.  
    • security: anyone remember when the iPhone took pictures of its users without their knowledge?
    • product quality: I am not interested in any iDevice because of the standard of software engineering and product management.  I am also not interested due to the restrictive rules of the app store.
    • freedom and flexibility: smartphones are good if they are flexible.  If I buy any device with gigabytes of storage, I want to be able to use it for whatever purpose I choose.  And, I don’t want to use any device:
    • with a proprietary connector which requires an expensive proprietary cable to connect it to a computer;
    • which uses a proprietary, “secret” protocol that my chosen computer can’t connect to; 
    • that virtually prohibits me from putting my own digital content on the device, rather than that obtained through the device vendor’s sales channel;
    • that supports in any way the obscuring of content I have a right to, or in some way supports an ecosystem where the alteration, deletion or other control of content is deemed “acceptable” through the EULA;
    • that limits me!
    • On this last point, it worries me that Google Inc are appearing to adopt the Apple way of doing things on their Nexus devices – and in their cloud software.  Not being able to use additional data storage (no SD card in a phone, in this instance) means a greater reliance on the Google way of doing things.  Android software is becoming less flexible with regard to media storage (the camera app no longer lets you select the photo storage location, for example, although Android still supports external SD cards and will utilise media stored on it).
    There is a greater trend also: that of the death of physical media and moving everything “into the cloud”.  There are a few fundamental problems with this:
    • Physical media can be shared and enjoyed by more than one person.  Sharing is not copying nor is it stealing.  If I am attending a family gathering – a party, say, then I am free to bring along a couple of CDs to play.  How can this simple act be replicated by cloud-only storage?  If we all use cloud-storage network devices at home, sharing a CD will become impossibly.  
    • One solution to this, touted by a friend, was to “bring along your iPod“.  Disregarding that I wouldn’t have an iPod, introducing this as a solution means I would have to ensure that my portable music player is up to date with all my music.  A solution to that is, of course, a cloud-based music service – iTunes and Google Play Music are two obvious contenders.  But there’s a further problem: connectivity.  Is a 3.5mm headphone plug to amp/speakers standard equipment in most households?  Unlikely.  So there my music stays, locked inside my device unable to be shared.
  • Books.  I can pick up a physical book, read it, share it.  I will probably get my book back if the borrower is respectful, thus I haven’t been denied it in the process of lending.  Can the same be said of eBooks?  Can one “lend” an eBook to a friend?  Perhaps.  More worryingly, though,, can it even be guaranteed that any digital eBook provider will not alter original material or remove any purchased books from my library?  Again, unlikely.
    • We begin to see, further and further, that DRM is abused by on-line content providers.  We are restricted in new ways that the old ways couldn’t (and shouldn’t) prevent.  It is troubling that access to information is price-controlled in this way; entire cultural values can and will be influenced by the (lack of) availability and slowly, surely, belief systems and perceptions of free thinking and free will may be curtailed, even ceasing to (legally) exist.   Hello, 2084. 
    This is why I will not lock my photo, book or audio content in any on-line silo.  I will always have off-line access to my copies of digital media and I encourage others to do this also.
    Does this make me a stubborn git? Or does this make me someone who is not prepared to endure extortionate business practices with items as important as art, literature and music…?

    Enhanced by Zemanta

    Posted on
    by
    facebook engancha
    facebook engancha (Photo credit: Wikipedia)

    Oh dear.

    Many bloggers and commentors have read Mark Cuban‘s recent blog about Facebook‘s edgerank story sorting algorithm.  One could argue that at the level of Cuban’s business, small problems become big problems quickly.  But, on Facebook as in most walks of life, being “large” does have some advantages.

    One advantage is Facebook’s Page Insights.  Let’s take the smallest business.  In Facebook terms, it’s this:

    • a one person profile with no friends
    • one page owned/managed by that person with several likes
    If you want to build up a following quickly, you need to build up some Likes.  Be Liked.  Or, at least, look like you’re liked.  You probably get the idea.  This is marketing, after all.
    So, how about running a competition?  Provide an incentive for someone to come and “Like” you.  How about asking current customers (those who, presumably, like you anyway) to submit a review and hit “Like”.  Great.  
    Except it’s not great, really.  To use Facebook’s Page Insights, you need 30 Likes.  Yes, it’s not a tall ask, but why?  The problems with Facebook for small business start with this innocent enough little idiom.  No, there should not be a 30-Like threshold to see who Like’d you.  There should be 1.
    Facebook’s habit of making it hard to access and understand your own data, or data relating to you, stems from the misguided notion that building up more visible momentum in your brand’s page means you’re more like to find Facebook “sticky”, and consequently more important (vital, even) for the success of your on-line marketing.
    Does Google Analytics insist that you have over 30 visitors per month to your site before it can be bothered to report this back?  
    Enhanced by Zemanta