Knowledge - Kunskap

Joomla logo

Joomla! is a Content Management System (CMS) software to handle a web site. The web site itself is stored as files in a file catalog, and in a data base. Joomla! is the software to create, update, administrate etc the entire web site - so normally no need to go into the file catalog or data base. This basic architecture is common for many web sites. 

Today I have updated this web site to Joomla 3.9.4 release, from the previous 3.9.3. The update process went well without any issue, and I have not seen any issue with the new release. This was a relatively small release with focus on security and bug fixes. 

The most common CMS software for web sites today is by far Wordpress. In the statistics I have seen, Joomla comes then far beyond, with Drupal on third place. 

I converted this web site to Joomla a couple of years ago, from a static html file site. When I am thinking back, why did I choose Joomla? I was mainly considering Wordpress and Drupal, beside Joomla. I was using Drupal already professionally, but only as a lower level administrator. I did not fully like to work with Drupal, but it could well be related to the specific implementation, and that I had so limited access. I also thought it would be nice to try something else. Wordpress was already then very popular. But it was more focused on blogs, and I wanted a CMS that was better designed for any and more advanced web sites, which I get the understanding Joomla had. Furthermore, Joomla is to my understanding the most independent and volontary built of all those Open source CMS's, which also attracted me. I have not regretted I selected Joomla! 

Even if this, and most updates, works without any issue, this is a good scheme for update: 

  1. Backup (and preferable download a local copy/somewhere else)
  2. Read release notes of Extensions to update (especially to understand if there can be any compatibility issue)
  3. Install Extension by extension
  4. Check if web site seems to be working normally
  5. Backup again
  6. Read release notes of the new Joomla release (including system requirements etc)
  7. Install the new Joomla release
  8. Is the "favicon" needed to re-install? If your template is Joomla-origin (not saved under new name), the Joomla-installation likely puts back the Joomla favicon. To put back your own facicon, you simply go the file manager of your web host
  9. Browse around the web site and check it works normal (especially features which release notes talks about)
  10. Read any "After installation messages" in the control panel
  11. Consider actions directly of those messages, especially security relatedor save to later
  12. Consider how I can take advantage of the new features in the new Joomla release (and in the extensions)

What is your thought about different CMS or other methods for web site? What do you use?

Do you want to try out Joomla yourself? Then I can recommend this free trial service! You can use it for trial purpose, but you can also keep it and use it as a real web site - free or paid versions. Try Joomla at!

Henrik Hemrin

16 March 2019

Write comment (0 Comments)

Alvesta kommun (Alvesta municipality), Sweden, has taken the decision to change from lease of IT equipment (laptops etc) to own themself.

This was decided by kommunfullmäktige (local government council) at the meeting 2019-02-26. See protocol, clause KS § 53, page 13, "Tilläggsbudget för investeringar av datorer i stället för leasing". The background is to get a better control of IT costs and also to become more cost effective. To achieve this they change model so IT department owns IT equipment instead of lease. Also the kallelse (notice to attend) to the meeting 19 March 2019 have more details of this topic.  

The newspaper Smålandsposten reported about this in the article 11 March 2019; "Kommunen slutar leasa datorer – blir billigare att köpa", by Oscar Ivarsson. When Alvesta lease, the computers are replaced exactly every third year, tells Pär Svensson. When they own themself, the article states, it gives a possibility to be more flexible and wait 4-4.5 years when possible. Of course still to keep a refresh rate that keeps the equipment modern enough. 

It is interesting to read Alvesta kommun conclusion they save money by owning and having control themself! To me, it is somewhat opposite a trend to rely more on external partners. It is still to see if this was correct decision or not. 

Extending the average life span for the computers is also good for environment, sustainability. I believe, even if a new equipment is more energy efficient, I do not believe technical development goes so fast that it would justify to keep three years refresh rate for sustainability reasons. With my own experience of changing computer at work, I know also for me with decent computer knowledge, that I will loose many hours, 1-3 working days in total is not unlikely, to get fully up and running at each replacement. 

Finally, I can't stop thinking of how much more it might be possible to extend the life time if the computers had been running on a Linux distribution instead of Windows. It is my assumption they generally use Windows today, although it is not stated in the reference material. I understand this is far from becoming a reality in any near. Some of Windows software have a good compatible replacement available in Linux, but will as always require learning.  But a bigger obstacle, I believe, is that they likely use more specific or custom developed software, developed for Windows only.

Can sustainability become a driver for a more widly spread usage of computers running on Linux?

Henrik Hemrin

15 March 2019

Write comment (0 Comments)

Linux Mint Desktop

Web browsers needs RAM memory! 

Web browser comparison with focus on Linux Mint browsers. 

There are a lot of web browsers out there. For various Linux distributions, for Windows and macOS, as well as for tablets and phones. 

How much resources do they need to work? 

I have focused on the needed memory, when showing same reference web page ( I have uninstalled browser extensions. Starting point is the Linux Mint operating system with only internet connection (via VPN) turned on, idling, and of course the ordinary background programs and processes. The values are noted directly from the screen - the screen dump tool itself used for the examples below takes some resources itself (therefore screen snapshot examples have higher values than shown in the table). 

Resource monitor - no load

Tested browsers

I have compared four browsers available in the Linux Mint repository. It means they available to download, install and update inside the Linux Mint program library. 

  • Firefox
  • Chromium
  • Epiphany / Gnome
  • Arora

Resource monitor of Firefox browser

Test result

Browser   Memory usage RAM [GB]  Memory usage RAM [%]
No browser "idling" 981 53,3
Firefox 1200 68,0
Chromium 1100 60,7
Epiphany / Gnome 1200 64,5
Arora 1000 58,1


This is a very quick study. Anyway, I think it is accurate enough to conclude it indeed is a difference between browsers. Many more browsers exist.

Memory resources is of course only one aspect of selecting browser. Security, privacy, available extensions are some other important aspects to consider - none of those are considered in this test.

When browsing, the needed memory can be highly impacted of which page is browsed, and if many tabs are opened at the same time. Not at least for a computer as in the test object with very limited RAM, this memory resouce aspect can be relevant to take into account when browsing the world wide web!

Test reference information

Operating system Linux Mint Cinnamon: 19.1, 64 bit

Firefox: 65.0.1

Chromium: 72.0.3626.121

Epiphany/Gnome web browser: 3.28.1

Arora: 0.11.0

Main characteristics of this computer: CPU: 1.60 GHz dual core, eMCC (SSD) Hard drive: 32 GB and RAM: 2 GB.

Henrik Hemrin

10 March 2019


Write comment (0 Comments)

OFC Plenary Session 2019

OFC Plenary Session 5 March 2019

OFC – The Optical Networking and Communication Conference & Exhibition

This big annual optical event is this year held in San Diego. The conference started with Short courses on Sunday, yesterday (Monday) the technical conference sessions started and today (Tuesday) also the Exhibition starts. All ends on Thursday. Today is also the day for this two hour Plenary session.

Intro of the Plenary Session

Beside information e.g. about awards, the Plenary Session consisted of three presentations:

  1. Towards Open Innovation in 5G, by Alex Jinsung Choi, from T-Laboratories Innovation, Deutsche Telekom AG
  2. Tackling Capacity and Density Challenges by Electro-photonic Integration, by Benny P. Mikkelsen, from Acacia Communications
  3. From Self-driving Cars to a Vision for Future Mobility, by Dmitri Dolgov, from Waymo

It is interesting that the first speech is about 5G; mobile wireless technology! I mean, it is an optical conference, mainly with a focus on fibre based optical communication, and plenary starts by talking about a wireless radio technology! But actually, it's not so strange. Even if 5G is about wireless radio communication between the device, the mobile phone and other “things”, 5G needs a lot of fibre optics as well as microwave links in many ways “after” the radio signal has reached the radio base station antenna. So, fibre optics is indeed relevant for 5G, and vice versa.

Also the last, third, presentation about self-driving cars is not really fibre optics. It would require long fibres to connect it to a driving car... Although the driverless car in the presentation used LiDAR technology, which is a laser technology, the connection to optics is indirect. The presentation didn't really tell much about how the car communicated, but 5G technology is definitely an enabler for the self-driving cars to talk to each other, and that way it absolutely relates to fibre optics.

The second presentation was more directly about fibre optics; component evolution.


Alex talked about three reasons for the need of 5G:

  • Mobile capacity / speed upgrade
  • Fixed Wireless Access
  • New products / solutions; Automated driving, Industry 4.0 and a lot more

He concluded “Collaboration is key to address costs, speed up deployment and accelerate innovation in 5G: Operators, Suppliers and Open organizations”.

Electro-Photonics integration

Benny said data traffic is growing faster than spending. Regarding energy, he said it is estimated that Information technology by 2030 will use 20% of the global electricity, not at least for Data centers and Wired access. So, to make the optical systems less energy consuming per byte is essential. A challenge for photonics is that there is not a single building block or technology, like you can have for electronics. Photonics integration is also still a young technology. The transport layer is going coherent, but max 64-QAM is reasonable, more will reduce distance too much. InP versus Silicon for photonics integration was discussed, both have its advantages, and as noted above, none technology can integrate all building blocks into one technology. Benny showed examples how rapidly the integration, the size of transport module has been reduced: from 100G MSA around 2012 to 200G CFP2 in 2017 having a forth of the former size, and 400G QSFP/OSFP coming 2019-2020 is about half of CFP2. Size is decreased plus speed is increased at the same time. Power and cost are also reduced per byte.

Self-driving cars

Dmitri held the final presentation, starting with a photo of the Google self-driving car trials in 2009. Next he showed a photo from 2015 with a Waymo fully self-driving car in real traffic, with only a blind person in the car. Waymo is a subsidiary of Alphabet (the Google mother company). Fully self-driving cars are in field trials. Waymo use several technologies, e.g. LiDAR for distance, 4x short range lasers for blind spots, 19 vision cameras, radars and microphones. AI, Artificial Intelligence, is used in three main areas: Perception, Prediction and Planning. He told that with a car fleet, e.g. a fleet of Waymo cars, they interact: one car comes into a road work, this car passes on this information to the other cars in the fleet so they can adjust their driving to the expected upcoming problem. Next is also to share in the fleet what each car is doing next (e.g. “I stop now”). He didn't tell how this information sharing is done, but I'm pretty sure 5G mobile networks will be an enabler for wide scale implementation.

Note about this article:

Above are my notes from the plenary session, via webcast attendance (free to attend for anyone). The facts I have shared in this article from the plenary session are correct as far as I understood when attending, using and adding my knowledge.

Note about the author:

I attended my first OFC Conference and Exhibition 1999, in San Diego. Now it is several years since my latest live OFC. My optics field has been as fibre optic Component Engineer 1994-2013, for various optical applications, at Ericsson. I have then continued to keep an interest in fibre optics. Currently I have a pause from any ordinary job to focus on family project. More of my professional profile is available on my LinkedIn profile. I am member of OSA, The Optical Society.

Henrik Hemrin

5 March 2019

Write comment (0 Comments)

I am a listener to the podcast "The Voice of 5G", from Ericsson. It is hosted by Paul Cowling and Janina Hedberg.

Ok, I am biasad with all my years at dear Ericsson, but I indeed do recommend this podcast for anyone interested in the evolution of mobile systems. It has a focus on 5G generation, which actually is here now!

Find it on any podcast software you use!

Write comment (0 Comments)



A few months ago I converted my backup computer from Windows 10 to Linux Mint, due to my computer was too weak for Windows updates. It's cool with Linux!

Linux is actually the kernel "core" in the software. When installing Linux on a Personal Computer, you select distribution (distro) and each distro has often several desktop environments to choose from. They vary in how "heavy" they are in resources, and some are more suitable for this or that type of work. So in comparison, in Windows world (or macOS), there is basically one distro and one desktop environment, while Linux have tons of them - and very many open source and free (macOS is a Linux sibling, but not free open source). As well as many free applications.

A drawback there are so few PC that can be purchased with Linux from start, but some exist (as seen from my Swedish horizon). Maybe, some signs, it is becoming somewhat more available now.

Anyway, Linux is very nice and interesting.

There are tons of articles and to read on internet about Linux. And of cours books to read. Or read a magazine like Linux Format. Linux Journal has ceased to exist, but their web site with many articles is still up and running. The article What is Linux? from is a good start to get a basic idea of Linux.

Talking about general about Open source and more, I like the podcast Command Line Heroes, from Red Hat. 

Another podcast I listen to is MintCast, about Linux Mint and Linux in general, and other technical stuff. 

Please see also my own list of articles with Linux tag

Henrik Hemrin

29 January 2019 (with later updates)

Write comment (0 Comments)

Linux Mint Badge

In my story about my Cheap laptop reborn, I wrote that I had replaced Windows 10 with Linux Mint 19. Main driver for that replacement was the big troubles to install Windows updates; too little capacity in my laptop.

I also wrote Linux Mint 19.1 was soon to come, and I was curious how that upgrade would work, considering that type of upgrade in Windows 10 was the reason for installing Linux Mint.

I can say happily, the upgrade to Linux Mint went very smoothly! Of course I first prepared with back-up and so. I also read the installation guide on Linux Mint websites about tips how to do the upgrade, and some additional actions. Just before the upgrade, I installed all other updates. Then, in the same update manager was also the Linux Mint upgrade. That upgrade took as I recall 5-15 minutes, and everything took maybe an hour for me as newbie in Linux. No real issue at all! It is now a few weeks since I did the upgrade, and no issue found. Sure there can be issues, but Linix Mint has good forums for support, both an international forum and several country local foras. 

Henrik Hemrin

19 January 2019


Write comment (0 Comments)

Cheap Laptop Reborn [Photo: Henrik Hemrin]


Half a year ago I wrote the article Short life time for my cheap laptop, about my two years old laptop which could not execute Windows updates due to low memory capacity. After the article was written, I did more trials, but I failed. I do believe it can be possible, for example by reinstallation of Windows and start from start. But so complicated handling should not be needed on a new laptop.

Now I have given the laptop a new life with Linux. After considering several, reviewing by reading and Live-DVD, I have installed Linux Mint. This Linux distribution is suitable for the characteristics of my laptop; memory is big enough with margin. Linux Mint is a distribution with many users, it has a relatively big forum for support, it has a very big software library and is seen as an easy to use distribution.

Installation went very easy, took less than 15 minutes. But. I had a severe problem that it did not start up, the boot did not find the installation… So here I had a stop with multiple testing and reading. Finally, I reinstalled but this time in ”EFI” (UEFI) mode instead of BIOS (legacy) mode, setting in the Boot menu. Linux Mint supports both booting alternatives. In order to have EFI to work, I needed to disable the Secure boot option in the boot menu. After this reinstallation, Linux Mint started perfectly! So, I must admit I had this installation issue. But after that issue, all has been working well for those first days after installation. And this issue was really to replace Windows with a completely different operating system. The normal case is that you purchase a computer with the operating system installed, so this kind of task is normally not done with Windows either by the average user.

Linux Mint, as well as other Linux distributions, are indeed user friendly. Maybe it can be good to know a bit about computers, but absolutely not a computer geek. Much software are included in the installation, so with some settings its ready to use. Linux, in difference to Windows, macOS or ChromeOS, are available in very many different variants; that is where the word distribution (or distro) comes from. And each distribution can be available for both 32 and 64 bits, and may also be available with different types of desktops.

I installed Linux Mint, Cinnamon desktop, release 19. In a couple of weeks will release 19.1 come, and it will be interesting to see how it works with update of the operating system.

Main characteristics of this laptop: CPU: 1.60 GHz dual core, eMCC (SSD) Hard drive: 32 GB and RAM: 2 GB.

As far as I have learned, this laptop which could not handle Windows updates properly anymore, and from that perspective was ready for waste, has no problem to work with Linux!

Final remark: Microsoft Windows is great in many ways. So is Apple macOS. But Linux indeed is also an interesting operating system, also for a normal personal usage (or job)!

Henrik Hemrin
19 November 2018

This article is also published on LinkedIn

Write comment (0 Comments)

How safe are your keys to your accounts? [Photo: Henrik Hemrin]

It must have been in the 1990's I got my first password for private internet purpose.

I started early with a paper to note down registrations and login info. Later it has evolved to a notebook for registrations, login info, software licenses, hardware info and more. 

I started with mostly pretty simple passwords, and reused them as well. The complexity of my passwords have indeed increased over the years. I have also worked to more and more not reuse same passwords at different sites, especially those more important where I would suffer more if someone broke in. Those decently secure passwords, unique per site, have been possible to change and still decently ok to remember for more frequent logins. But notebook has been needed for all as backup memory.

Over the years, it has also become more difficult to find the objects in my notebook, difficult to keep them in any sorted order. And the trouble when I don't have the notebook nearby. And the laziness to look into the book. I have many registrations, far more than hundred!

Some codes have also been important to always have access to in my pocket. So for many years I have also used an application in the mobile for important codes.

I have over time become less comfortable with my password handling. At the same time, I have been hesitant to store passwords digitally. A paper notebook, as long as it is not stolen, is a safe place to keep them.

I have read many websites and articles about passwords. I plan to list some sources for internet privacy and security I consider useful in a separate article later.

I have read that a good, strong password is not critical to change regularly. But it must be changed if it is revealed somehow. I have also read that one method, which can be safer than having less strong passwords, or reused passwords between registrations, is to not remember passwords and instead always use “I have forgotten my password” and generate a new password every time.

Well, I concluded I want to have my passwords digitally stored in a Password manager instead of my in my notebook. 

If I now should start to use a Password manager, I wanted a product that can do more than only handle logins. 

Some of my criteria for a Password manager:

  • Secure and trustworthy
  • Possible to use on multiple devices; automatically synchronized
  • Relatively easy to use
  • Available for multiple platforms and device types
  • Handle not only passwords, but also e.g. pin codes, software licenses and other info I have in my notebook

Regarding access to the Password manager from multiple devices, I believe any such solution is a higher risk than a more stand alone solution. But it is so convenient.

After reading many articles and web sites, and trying a few solutions, I decided for “1Password”. It is a paid software. When reading articles, their own information including their white paper (although the white paper still has some non-written sections), I concluded I feel decently confident that there solution is secure enough. Surely, I do not understand all I read. 1Password has competitors, both commercial and open source and non-commercial, which to various degree meets my criteria.

With the Password manager it means I only have to create and remember one password. But this password must be strong, “impossible” to guess or test out, and not at least I must remember it.

When I migrated to the Password manager, I took the opportunity to clean up and terminate some registrations.

Generally I generate passwords which are maybe 30 characters long, with a combination of upper case, lower case, numbers and symbols. The Password manager automatically creates such passwords; I can input how long and how many numbers and symbols I want. It can also create based on words. Those very long generated passwords strings are impossible for me to remember, and very difficult to guess or will take long time for a computer to try out. If someone get access to the data base of the registration, it can of course be revealed.

When I have created new, strong, passwords, I have seen that some sites do not allow so long as 30 characters, nor all allow symbols. Some sites requires the user to use, I would argue, too unsecure passwords. 

Once I have crossed the line to give up to insert passwords manually and store them in a note book, it is no problem the passwords are long and impossible to remember. And it is not a problem for me to change them, I do not need to have a system to change passwords so I still can remember them.

The Password manager also helps me to analyze: reused passwords, weak passwords, check if my registration may have been leaked (Integration to “Have I been Pwned”), and more.

Beside strong passwords, I consider it is worth to use two-factor-authentication (2FA) where available, e.g. by SMS, a software code generator or hardware. My Password manager has a built in code generator, so I can often use that one. But I am curious to try out YubiKey physical solution.

Furthermore, I can store other codes, software licenses, free text objects etc. And I can add more information than the password to the registration. I can even store important documents. And I can add tags. All in all, a Password manager gives me a good overview of my passwords and other objects.

This is where I am today on my password journey! What about you?

Henrik Hemrin
17 October 2018

Write comment (0 Comments)

Phone booth and bust outside Ericsson former headquarter "HF". [Photo: Henrik Hemrin]

When I was young and blonde (now I am less young and blonde), I joined Ericsson 1985. 

Over all my Ericsson years, I have been in internal and external contact within Sweden as well as globally.  

When I started my journey at Ericsson, paper mail was the normal communication method. Especially for documents. Of course beside the landline phone, which was extensively used as well. A nice thing with paper mail is that after the envelope is posted, the task could I  rest for a while. 

For short and very urgent messages we had telex. We had a paper form to write in the text, and handed over the form to the secretary, who had access to transmit telex messages. 

Actually we had already when I started an internal global electronic mail system; Memo which was developed by Ericsson, Volvo and I think some more companies. My manager urged us to check e-mail (Memo) once a day. A routine he suggested was to check in the morning while changing from outdoor to indoor shoes. In those days the PC was not invented, we had a mainframe terminal, shared by 4-5 persons. Later a few other big companies were possbile to reach via Memo on the mainframe terminal. 

Several years later, the fax (facsimile, telefax) machine arrived. What a great invention! Now we could send messages we had used telex for by ourself, also when secretary was not available. And not at least, documents were possible to transmit. 

I come to think of the Ericsson slogan "It's all about communication. The rest is technology."

And indeed what an evolution, or revolution, we have had and still ongoing, with communication technologies!

This has happened over only a few decades. The fax machine is already outdated (at least in most business). The landline phone is also halfway outdated, and the mobile phone is a very common tool. E-mail is well established, not only at big companies like Ericsson who had Memo back in 1980's. We even can read the e-mails in the phone. And we have SMS and numerous chat programs in addition. We can share and colloborate with documents stored somewhere over internet, e.g. in the cloud. And the video conferences which recently required equipment in special rooms can now take place via laptop or mobile phone (although more professional video rooms still can be relevant for more advanced video conferences). 

It's all about communication. The rest is technology. 

#communication #technology #Ericsson #telex #fax

Write comment (0 Comments)