John gave a presentation marking our 16th birthday on topics covered over the past year. David queried whether the Raspberry Pi pop-up shop had closed and John said that he assumed it had as no-one had mentioned it for several months [it no longer appears in the list of shops in Victoria Centre]. David also said that an errata had been released relating to the GPIO pins on the RP2350 because a supplier had messed things up; unfortunately, if a pin is in an undefined state, it does not go high or low. Rather it creeps up high when you expect it to go low which affects some boards. This is mainly a problem for manufacturers rather than for hobbyists as there are workarounds and it might be fixed.
Bernie gave a talk on the Mars Rover’s unique suspension incorporating a rocker arm, bogey and differential cam mechanism which keeps the payload at the same height while keeping the wheels on the ground all the time. It is all done with linkages which ensure that the movement of one wheel up or down is matched by corresponding pressure on the other wheel to keep it in contact with the ground. This YouTube video is an animation of the action while this YouTube video of a scale model of the rover suspension demonstrates its operation.
Brian commented that nmap is not working as it used to [as from 7.90, it changed its licence and is no longer considered free; the alternative would appear to be ZMap].
Darren is working on a demonstration of AWK, the data extraction program. He demonstrated some examples of basic conditional printing and of combining patterns to achieve more sophisticated results.
Bernie has been working on a console based interface which he can use with SSH to manage devices controlled through the Instrument Neutral Distributed Interface (INDI) using Python and the ncurses library.
In the specific example he demonstrated, he sent a new target to change the temperature. But in practice, by setting vectors to be values, you can have the controls to manage multiple devices, as long as there is a driver for the device. It can be used with any instrument though Bernie has in mind those using INDI.
As we were not able to have the expected presentation, we just discussed things we had encountered.
David noted the takeover of sudo
by systemd
.
Mike enquired about loading tailscale onto his Huawei smartphone and was recommended to use F-Droid.
Mike has been getting on with MODX but had problems with cPanel; Brian recommended looking at Giraffe Academy which offers up-to-date information on things you can do in the HTML and CSS rather than Javascript.
Bernie had circulated a Python3 script to address the first of the challenges set by Darren at the previous meeting.
The inclusion of an f"<string>"
in Bernie’s script prompted a discussion of f"<string>"
s. Bernie explained that you can include a variable within a brace in the string and also that you can use a format specifier followed by a :
in the brace. David noted that every language has different format specifiers; C got them from the Fortran format
operator.
Mike raised a problem he had had. Having changed a setting, he was unable to get back in to change it back. He knew where to make the change but could not find a way to get there. John suggested SystemRescue which has the virtue of not touching anything unless you tell it to do.
Once running, enter:
fsarchiver -v probe
to identify the partitions and their names. Mike can then mount the relevant partition in /mnt
, go into the partition, make the change, for example, with nano
and quit.
Calyx meet was down for maintenance and Brian wasn’t around to invite people to Discord; so we used the openSUSE Jitsi instance.
Darren said that at the York CoderDojo he had had a go at code golf in which people aim for the shortest possible code to solve a particular problem.
Mike said that, while Ansel, the fork of darktable, is being cleaned up, it has still got a fault in it; so he has been using Rawtherapee + GIMP but will go back and look at Ansel; Bernie noted that there has been a new release of darktable at Flatpak.
For the first of our new style online meetings, Bernie, Darren and John started on Discord while Steve and Mike started on Calyx meet before we all moved to Calyx meet where we were joined by David and John W.
Mike has had a problem with sound disappearing; John suggested that he use PulseAudio to diagnose which sound sources are recognised and whether any have been muted. Mike has also had a problem with darktable and has been told he needs to get a coredump. But for that he needs the devel files and to compile darktable with -g
set. Steve looked up the source on github which provides all the information about how to build darktable.
Transport problems prevented two members arriving and delayed the start of the first of our planned quarterly face-to-face meetings; we began with a couple of news items.
Bernie reported that there was a pop-up Raspberry Pi shop in the Victoria Centre in Leeds. Buying them from a shop was a bit different from ordering them online!
John started to present the Fifteenth Birthday presentation but did not notice when his notebook needed plugging into the mains and ended up describing it rather than presenting it! David S mentioned that David Carpenter is using Oracle Cloud Free Tier. He also mentioned a problem with the Let’s Encrypt challenge; having set up auto-renew for a domain, he set up a manual challenge for a sub-domain but, when he wanted to change it to auto-renew, he found that the Let’s Encrypt database had it down as a manual renew and would not let him set up auto-renew.
As no-one had anything prepared for this meeting, it was largely taken up with discussion of queries.
Brian mentioned that, on one laptop, the wi-fi was slow to recover from sleep; separately he had also been helping a friend whose wi-fi would not work. He had tried a USB dongle but this would only work if the laptop wi-fi was disabled. John said that, when he had been having problems with wi-fi on a friend’s laptop, it had been suggested that he use:
rfkill list
to find out whether it was a software or a hardware problem. He added that a friend who had been able to use a wi-fi hotspot on his smartphone to connect his laptop to the Internet had suddenly found that it would not work and later found that it would. John had gone on the Internet and found lots of reports of wi-fi problems and loads of solutions for them.
David had purchased a number of upgrades for his 3D printer: a new motherboard, an extruder which can cope with higher temperatures, a new display and a filament runout sensor. He commented that he had lots of wiring to do to add these upgrades!
John briefly summarised a presentation about SUSE’s Aeon:
David unboxed and unwrapped the Libre Computer Board AML-S905X-CC, otherwise known as ‘Le potato’, which he had ordered. It had cost around £30, that is, rather less than a Raspberry Pi 3, and had come from Ali Express in about two weeks. He had also bought an Orange Pi 4 LTS for the same money but it did not work. On checking he had found that it draws 1/4amp. He would like to run both from the same power source. Brian suggested that he return the Orange Pi to Ali Express and tell them it did not work.
This led into an extended discussion about the merits of various versions of the Raspberry Pi, etc.
Darren had asked a question on the mailing list about array based programming and there was a discussion about this, including a reference to its antiquity [see Array programming in Wikipedia]. This prompted John to mention key values which Bernie said are used in Python dictionaries; these were originally unordered and then a way of making them ordered was created until a change in the underlying code made them ordered by default.
Bernard had mentioned Nostr on the mailing list, a decentralised alternative to Twitter, but no-one had direct experience of it.
John mentioned at KDE has a Mastodon client called Tokodon.
Brian mentioned the Ulanzi clock which offers a range of functions beyond telling the time, including the weather and the number of social media followers you have as well as coming with the awtrix python script for Home Assistant and the option to install further programs.
Brian has been looking at NixOS, a Linux distribution built on top of the Nix package manager. There is a description of it in Linux Downtime Episode 65. In relation to using the Nix package manager with a different distribution, David anticipated that there might be problems with dependencies and consistency with another distribution.
Brian had also been looking at how many virtual managers you can nest as discussed in Linux After Dark Episode 36.
Unfortunately, BCB was unexpectedly closed and so Bernard, Darren, David, Mike and John H resorted to Wetherspoons while Nick, Brian and John W joined us online. However, because of the noise and feedback in Wetherspoons it was only practical for one or two people to communicate online from Wetherspoons. So conversation was fragmented and became further fragmented when David and Mike went away to try and sort out the audio on Mike’s laptop.
John reported on his successful installation of a Let’s Encrypt certificate using certbot in manual mode. He had first downloaded certbot
to his computer; he had then gone to the webroot folder on the website, that is, the one containing index.html
, and created the folder .well-known
and then, inside that, another folder called acme-challenge
so that he had /.well-known/acme-challenge/
.
John said he had been at a hybrid meeting with Tim Berners-Lee the previous day when Tim Berners-Lee had explained what he meant by Web 1, Web 2 and Web 3. Web 1 was the era of static websites based on Netscape, though the original design of the web had included the possibility of editing it. Web 2 was the era of server based websites developed by programmers though his intention had been that the web should be WYSIWYG. The problem with server based websites was that the data was held on a server which was a long way from the user and had to be retrieved every time and which was not under the control of the user. Web 3 is about giving back to users control of their data by creating decentralised storage over which the user has control; so, for example, you would control your health records and give permission to your doctor to use them. Web 3 is being developed by the Solid Project which he invited developers to join.
Brian shared the collaborative tool Figma which Adobe have acquired; it is aimed at improving the user interface and user experience.
He also shared Cloudflare Turnstile which is intended as a free replacement for CAPTCHA.
Brian said that, though he had used Node_RED to control the automation of thermostats (see November 2021 BradLUG meeting), this had proved unreliable because Node-RED kept rebooting at random times; he had discovered that this was probably linked to unreliable dependencies.
As BCB was closed, Bernard, David and John gathered at Wetherspoons where, by combining battery resources, they were able to hold an online meeting with Brian, Nick and John W.
Nick gave a presentation on Conda which was originally known as Anaconda and developed for use with Python/R but is now in more general scientific computing use. It is essentially a configuration manager; it does not replace anything else but allows you to manage different packages and versions of software in different environments without conflicts. It ensures reproducibility which is important for researchers when they wish to share findings.
Brian had been able to set up Asterisk and knew that he could make outgoing calls. He demonstrated that his mobile showed up under ‘mobile shell devices,’ he was successful in calling Nick’s ’phone and the quality was all right at Brian’s end. However, when Nick tried to call him, he got Brian’s mobile voicemail. John mentioned that, in setting up some new cordless ’phones at home, he had found his provider began its answerphone message after four rings. He suggested the problem might be his provider’s settings.
David showed how far he had got using his 3D printer to create the ESP32-Cam Pan&Tilt as described in the Random Nerd Tutorials which he had first mentioned at the January meeting. He demonstrated the USB plug he had made working as intended.
Our second attempt at a hybrid meeting was less successful than our first with problems with both video and audio.
Darren had been exploring Bash and in particular the various options for using brackets; there is a good article on Linux.com exploring the various options.
Shi writes:
It has been great creating the shows with the other Stuffers (heh) who have become some of my most favouritest peeps.
Firstly, wow — we managed seven years worth of consistent (lol) unadulterated tech comedy opinion-based content, about 87 or more episodes in total.
We met for the first time in two years at Bradford Community Broadcasting and also had our first hybrid meeting with Brian and John W online.
Brian asked a question about searching for someone when you have their last address but are not sure whether they are still there which generated a number of suggestions, none of which appeared conclusive.
Brian said he had gone back to using a PBX as the interface for cordless ’phones and his mobile. The mobile connects via Bluetooth but the audio quality is poor.
He had discovered that the Raspberry Pi 2 is the minimum on which you can use NordVPN with which he is using the Raspberry Pi as a gateway.
Brian shared a problem he was having with tailscale which uses WireGuard; he had tried to transmit out to a network but it did not work. In Spain he can only watch the BBC on his computer but he can use Vivaldi to cast his desktop to the TV; in this way, he can log in to the BBC and then cast the programme to the TV.
Darren had been having problems with Kontact and was unable to use the Calendar; John suggested he locate the Korganizer std.ics
file which can be opened in other calendar programs. John had done something similar when there were problems some years ago with Kontact.
John went on to share a script for backing up mysql/mariadb databases:
John presented a short quiz to mark 30 years of Linux:
Darren reported that his DVD drive door opens whenever the machine is returning from sleep; a couple of suggestions were made: that he checks the BIOS firmware and that he checks the boot order to see if the DVD is selected prior to the hard drive.
He is continuing to explore Picroft.
He showed a Bluetooth speaker he had acquired to amplify smartphone audio.
Darren began by sharing what he had been looking at in machine learning and AI: Siri/Alexa/Picroft and a number of personal projects including
As no-one apart from Brian had brought anything to share, the conversation roamed across a range of non-computing topics.
Brian had however solved the problem he had had over booting a Raspberry Pi from a USB drive.
David shared the rather underwhelming photo of BepiColumbo skimming past Venus.
Bernard shared some more of his work for the Astronomy centre, focusing on the Aladin client. One of the problems in astronomy is determining a zero point from which coordinates can be calculated. Traditionally the zero point had been determined as the equinox but it is now determined by using a catalogue of distant objects which are apparently stationary but whose positions can be determined. This has led to a formal definition of the International Celestial Reference System (ICRS) which the Python package astropy will convert by using a website which gives the earth’s position at present.
Brian had been caught in Covid-19 related travel problems and was having to join us using his Raspberry Pi tethered to his smartphone to create an Ethernet connection. He commented that he was able to use iView Australia without any problems.
Brian asked about people’s experience of get_iplayer
and John said that you needed to keep up with the latest version, which Brian had, but John had had no problems with it except when he had not updated it recently.
Brian then expanded on how he had added Node_RED to Home Assistant demonstrating how he could add a gauge by pulling elements from the left hand column. However, he had had difficulty getting Home Assistant to connect to the Internet.
David had set up Home Assistant in a Docker container. There are four ways to install Home Assistant:
Brian showed a device he had which measures particulates, in particular the PM2.5 particulates which are particularly dangerous. They had recently experienced sand being blown onshore from the Sahara but there had been none of usual cases of people being affected by the sand particles because people were wearing masks because of the pandemic. Bernard said that he had once experienced sand particles on snow when skiing; when snow later fell on the sand, it turned orange.
Brian finally managed to sort out John’s audio by clarifying that in PulseAudio the settings in the Playback and Recording tabs should be 100% and any volume adjustments made in the Output and Input tabs.
As there were still problems with the sound on John’s new laptop, we started with a discussion of sound on chromium, whether it might worth trying Firefox, which did not recognise John’s external microphone, or whether it might be worth trying another microphone, without coming to any satisfactory conclusion.
Brian, John W, Bernard, David, Darren and John H joined the meeting this month. Brian began by describing some of the neighbour trouble he was having before
Bernard demonstrated how the content of the four projects contained in LXD containers on the Webparametrics website
As no-one had prepared anything specific for the meeting, the conversation wandered over a wide range of computing and non-computing topics.
Brian has swapped from Digital Ocean to Amazon because he only needs a web server and not a website but he was puzzled by the output of free -m
which suggested that he had very little free memory. David explained that the Linux kernel uses whatever memory there is for cache and so will reclaim memory from cache if it needs more than the free memory available.
Brian shared the problems he was having connecting over ssh
behind carrier grade NAT. A number of possible solutions were discussed including using wireguard or socat
or following the SSH Port Forwarding Example and the problem was eventually solved.
David S is still looking for a decent Android text editor. This query led on to a discussion of Android Firefox problems. Bernard, Darren, Brian, David, John and, later, Nick joined the discussion.
Brian shared a number of problems he was having configuring a VPN with the Microtik router OS; the only suggestion people could make was to use Wireguard instead for what he wants. Brian also mentioned that he had had a look at Boxee Smart DNS as a possible way forward.
Unfortunately, there were problems with the audio in particular this time which meant that several people who joined us left the meeting. For those who remained
Darren demonstrated a simplified version of cat(1)
, written in Dlang. It had only one loop, two variables, and three function calls to the D standard library.
Bernard demonstrated using Python virtual environments.
Darren drew attention to the announcement that Lenovo will be supporting Linux across its range with Ubuntu and RedHat and providing full web support. John mentioned that the number of Linux desktops connected to the Internet had now overtaken the number of XP desktops and was approaching the number of Windows 7 desktops; however, there was a long way to go to overtaking the number of Windows 8 desktops.
Ten people, three cats and a hamster participated at various times and in various ways in our second online meeting.
David reported that he had managed to install the Ubuntu 20.4 Mate image on his Odroid but had encountered various problems and was now awaiting the Arch ARM image.
Brian, John, David, Shi, Kriss and Yoghurt took part in a Jitsi meet.
Brian demonstrated the Paperwork which allows you to store documents in any format, including image formats, and then search (for) them using the inbuilt OCR which gives it an advantage over purely text based search engines.
The absence of any reports on the meetings in February 2020 and March 2020 did not mean that the meetings did not go ahead but that those attending pursued individual projects and there were no presentations.
The Covid-19 pandemic means that we are unlikely to meet face to face in the near future but we are exploring the possibilities of virtual meetings.
Keep in touch through our mailing list.
Mike had had problems applying a patch to dhcpcd
and so David S talked him through the process while the rest of us got on with the meeting.
David had been demonstrating shaders in GIMP and Mike sharing his experiences with broadband and servers when John arrived rather late with a demonstration of using free and open source software to do something which had originally been done in proprietary software.
After an exchange of various news items, Bernard mentioned his visit to the Thought Bubble Festival in Harrogate the previous week where a wide range of novel and comic book authors had appeared; Bernard had attended a panel on web comics which had looked at the artistic issues and the technical ones — specifically that web comics do not pay, though it is possible to raise money through patrons or kickstarter funding.
Mike raised a problem he was having with DNS and Rob, joining us once again after a long absence, explained that the big players and the Content delivery networks were effectively operating a new version of DNS. The only answer was to get a domain hosted by one of the majors like GoDaddy. He went on to say that, notwithstanding the objections from state actors to encryption, end to end encryption would become the default with IPv6 and IoT because it was the only way to make IoT viable. Whatever happens, it will involve changes to hardware, firmware and the Linux kernel. Interestingly, the US Navy which uses Windows is using Linux containers for security.
Mike had encountered a problem with Postfix in that it didn’t start after it had been stopped for a reboot. A quick search revealed that a similar problem had been around in 2016 in both the RedHat and Debian versions of Postfix when it had been traced to a file being left in the wrong place. After discussion, it was suggested that Mike write a script which periodically checked that Postfix was running and then started it if it was not.
Brian had hoped to demonstrate Magic-Wormhole which allows command line communication between two computers where the sender enters:
wormhole send <filename>
which generates a code which the receiver can use when prompted by
wormhole receive
to receive the file. However, Internet access was down.
Bernard showed us the results of his infra-red photography kit, powered by his Raspberry Pi. We saw, after some image enhancement in VLC media player, a hedgehog wandering past his hide, a crate in his garden [there was some dispute later as to whether the creature was a hedgehog or a rat].
Mike left the explanation of how to configure a server to allow a single IP address to serve four domains, each configured as a subdomain on the server, until next month when Brian will be back and gave a presentation on darktable. He illustrated a variety of effects, how you can organise the right hand pane to reflect your personal workflow and how easy it is to access and work with the history feature.
Mike tried to explain to Brian how he configured his server to allow a single IP address to serve four domains, each configured as a subdomain on his server. It was suggested that Mike prepare a piece on this for a later meeting.
It was noted in passing that the Windows Subsystem for Linux is getting a Linux kernel.
Bernard demonstrated the Python Package Index for which anyone can write packages. He showed how you could set it up and then how you could download a package to a virtual environment with:
python3 -m venv ~/v5
where v5 is a virtual environment in userspace. To activate that virtual environment, you enter
source ~/5/bin/activate
John noted that Maplin is back as an online store. In response to Mike’s account of the problems he had had trying to install Arch on his computer, John suggested that he could delete all the existing partitions on the hard drive except the very first (very small) one by using System Rescue and then start the installation process afresh.
John managed to demonstrate System Rescue on his own computer by turning off UEFI, using Legacy to load it — though it would only work with the VESA drivers on his computer — and then reverting to UEFI. He said that the documentation is excellent but that they have their own way of creating a bootable USB which John had found you could get round by creating the CD version and then copying it to a USB.
The meeting began with a range of chit-chat. John H, commenting on a note about solution focused journalism, remarked that a very good journalist had told him that you always end a piece with something that left the reader thinking, not a neat solution. This led into a discussion of the principles of writing a good article and how, translated into radio, the principle that there should be a new point at least every 90 seconds was well worth following.
Darren reported that he had not been able to download a version of BlueJ which was compatible with the version used by the Open University.
Bernard began by demonstrating Stellarium, the open source planetarium.
John H then asked about created a looping video to run on a display probably using a Raspberry Pi.
Mike asked about getting a new computer on which to install Linux and John suggested he have a look at PCSpecialist in Wakefield from whom Brian had obtained a laptop which he was very happy with.
Brian shared a problem he had with KDE Activities; there was a Default activity on the desktop but, while it was possible to give the activity a blank name, it was not possible to remove the icon identifying it.
He also mentioned a problem with File Associations for which he had downloaded a separate program but John was able to show him System Settings->Applications->File Associations which allows full configuration of file associations.
David C joined us briefly to share progress on open sourcing BCB; he has been able to set up JACK using Rotter as the audio logger.
Brian demonstrated Glances, a cross-platform system monitoring tool written in Python, running in tmux
on his server.
He then said that he had installed Nextcloud using a server running on a Raspberry Pi. This is relatively easy on a Raspberry Pi 2, less so on a Raspberry Pi 3. It involves downloading the server image onto a desktop computer, copying it onto an SD card, putting this in the Raspberry Pi, booting it and then updating the image.
Brian asked about Wayland which did not seem to work well with Cairo Dock; John said that Wayland with KDE Plasma was an option in openSUSE Leap 15.0 but it did not work well yet.
Darrenshared his experiences at the June Leeds Code Dojo meeting when the programming challenge was to write a parser for Befunge whose code is written on a two dimensional grid and uses Reverse Polish Notation. Befunge was originally written to be as hard to compile as possible though compilers do exist for it. He showed the parser he had written in D.
Brian showed us his new laptop from PCSpecialist running Linux Mint with Cairo Dock and recalled that he had been looking for a replacement for Tomboy because it does not synchronise well and cannot show anything other than text. He had found Joplin which uses Markdown and, following a recent request, now has a search within notes feature.
Oliver shared his recent experiences of the i3 tiling window manager. It is very easy to flip between tiles and between tiles in different workspaces which makes it easy to move between different terminals. i3 has a lot of add-ons but mostly they add bling.
Darren brought a problem he had had with some wi-fi headphones but, after various attempts to find a solution, we concluded that there was a hardware compatibility problem.
John thanked members for their contributions at the previous meeting to the GDPR presentation which had been well-accepted by non-geeks. He went on to highlight a number of changes to HTML and CSS. Ostensibly there had been very few changes to HTML — such as the removal of the <keygen> and <menuitem> elements — but the apparently superfluous <main> element which had been added four or five years earlier had been revealed as the foundation for some far reaching developments.
John shared a presentation he was developing on GDPR for small voluntary organisations. David S commented that the test for organisations would be ‘have you made a bona fide attempt to meet the regulations?’ He also commented on the three different uses of ‘loss’:
Brian described how he had reflashed his smartphone and his tablet. With the demise of CyanogenMod, LineageOS has taken taken over this space. First go to the Wiki and find the codename for your device; then click on that for the instructions for your device. Note that these are overcomplicated and many steps can be ignored.
Go to OpenGApps where you need to locate your Android version and your processor. You can also choose the level of Google service you want from minimal to maximum. Download the relevant zip
file to your computer.
Darren had brought some cakes for us to celebrate his birthday and mentioned the Krack vulnerability in WPA2. David S referred to the part of this press release which refers to the early release of a patch by OpenBSD and the exclusion of OpenBSD from early notification of future vulnerabilities.
Bernard demonstrated the software he is developing for the Todmorden Astronomy Centre to enable members remotely to control the Remscope, a robotic telescope currently being constructed at the site.
Shi brought some cakes, including a beautiful chocolate cake, to celebrate our ninth birthday.
Kriss and Shi introduced WebAssembly on which all the browser manufacturers have agreed to work. WebAssembly provides a virtual CPU which maps to the actual CPU in the device on which you can run C programs compiled to run on the virtual CPU. It operates at a lower level than the Java VM and the code, which runs closer to bare metal than anything else, will run in any browser — as long as the browser manufacturers are not lying. Because it runs in a sandbox, it is as secure as Javascript.
As a result of questions by Ash at the previous meeting and John W at this one,
John H demonstrated VirtualBox with FreeDOS running inside it. He has yet to install any DOS programs to run in it!
Brian introduced AppImage which provides a way of installing packages directly from the maintainer without going through a distro.
As no-one had prepared anything,
Brian mentioned that his search for a replacement for Tomboy had led him to Apache Guacamole which is currently an Apache Incubator project.
We welcomed Ben, a Python programmer from Cambridge, who was on a working trip to West Yorkshire.
Brian asked about notetaking apps because Tomboy was no longer synchronising properly. He would prefer a web-based app and had looked at Minimatch which uses NPM.
This provoked a discussion about developers dropping features.
Then, while David S led a private discussion at one end of the room,
Only Stéphane had announced something to share; so
John W asked about freezing rows and columns in LibreOffice Calc. This has changed recently but involves placing the cursor in the highest cell on the left hand side which you do not want to freeze and then selecting Windows->Freeze in older versions and View->Freeze cells in the newer versions.
As only David had come with anything to share, we rambled round a wide range of topics.
Nick, who was with us for the first time since 2015, showed us the ThinkPad he had bought for £80 on eBay and told us that he had moved on from SkyBet to Leeds University Department of Engineering where there is a lot of Linux, mostly CentOS and using Puppet, and a wide range of computing resources up to an HPC cluster which is used by, among others, the European Space Agency.
Darren shared some of the problems which had appeared on the Open University TU100 My digital life forums relating to the SenseSense programming language which the Open University have developed from Scratch for use with mature students. Darren himself had had a problem because his 64-bit OS was just that; it had no 32-bit libraries.
Roger who hails from South Yorkshire and had stopped by on a return journey from Sutton Bank shared his experiences of using Linux with the PICkit and PIC microcontroller.
David S did a presentation on configuration management or how to make sure that everything you need is set up as you want it to be whether on one or on a thousand devices.
As no-one had prepared anything specially for the meeting and David S was occupied trying to get Adobe Flash to work on John W’s computer, we chatted among ourselves with Brian and Ash sharing their experiences of Manchester BarCamp. The arrangements had been better this year with half a dozen lecture rooms available. Brian had given his IoT talk which he had tried out on us the previous month and they had enjoyed sessions on Hacker Packet Radio and Git.
Brian gave a demonstration of live messaging between ‘things’ using MQTT in which members were encouraged to participate; this involved installing Mosquitto, a message ‘broker’ for MQTT, and then connecting to the temporary wi-fi network which Brian had set up.
John H announced that David C was moving back to the area after his wife had obtained a job in Leeds.
John showed his Intel Compute Stick; unfortunately, we did not have a female HDMI connector to enable it to be demonstrated.
Darren described the on-going saga of trying to get Slackware 14.2 running with LVM where he had made progress but not found a complete solution.
John H shared a video he had made of a student presentation on prototyping in 1987; students had been divided into groups of four to research a topic and his group had decided to present their results by way of a series of sketches. At the time development mostly involved COBOL and programming only started after the requirements had been fully specified which normally meant that, by the time the program was delivered, things had moved on and the program no longer met the needs of the organisation. The proposed solution was prototyping of a model of the program to get user feedback before embarking on the programming or building the entire application by prototyping through a series of iterations in much the same way as free and open source software is now developed.
Brian demonstrated in this presentation how he set up a Raspberry Pi 2 as a router essentially by setting up a static IP during configuration and then handing over to a DNS server.
John W asked the best way to link together a number of computers and NFS or Samba were suggested.
John H talked about the background to and the work of Claude Shannon, the centenary of whose birth fell on 30 April 2016.
David S had hoped to be able to demonstrate BASH for Windows though he had found that he had to sign away all his rights to register on the Windows Insider Program and, when he had done that, found that the relevant option had not being installed on his tablet. So all he could do was point to the BASH on Ubuntu on Windows site.
John H picked up on a discussion at the previous meeting to give a presentation on dBASE II. He had never upgraded to dBASE III because it was not backwards compatible with dBASE II (other programs of that era like WordStar and Supercalc had maintained backwards compatibility; so it was possible to use them on both CP/M and DOS machines) and because dBASE II had an operator similar to LIKE "%<substring>%"
in SQL which had not been implemented in dBASE III. As he had made extensive use of this operator in his programs, an upgrade to dBASE III would have involved an extensive rewrite of all his programs.
Alice started us off with Optimising Impala Queries, or a ‘Distributed Lego Community’, a demonstration of the principles behind Parquet, a columnar storage format, and Impala, an analytic database, for the Hadoop ecosystem. Columnar storage formats overcome the burden of reading every row of a table based database such as SQL.
With no presentations prepared, we talked about this and that, from Elixir, a concurrent programming language that runs on Erlang, to openSPARC.
Brian introduced us to the Pine 64, an expandable single board computer starting at $15 for 512MB. Though a 2GB version was advertised, it appeared that only the 512MB and 1GB versions are currently available.
Stephane then recommended the Charbax videos and in particular the interview with Bernhard Rosenkränzer on the Android team at Linaro and Rob Clark of Red Hat who works on the open source GPU driver called Freedreno for Qualcomm’s ARM processors’ Adreno GPU. He noted that ARM GPUs are all bound to specific implementations of the GPU which makes producing common code very difficult.
John H began with a presentation on the background to the recent release of openSUSE LEAP 42.1.
Alice then demonstrated using the Realtime Trains API to download and analyse information about train movements on Train workings; the source code is on GitHub.
John H described the work he was doing on the Heath Old Boys Association website; this was a 2003 vintage frame based website which did not play well with modern devices; after he had explored various options, he had decided that the best option was to build a new HTML5 website on the lines described by Dave Fisher in his 2010 talk to BradLUG in front of the old website so that people could continue to access the old website while the new one was under construction.
A select group of members gathered to celebrate the seventh birthday of BradLUG; there was cake and then John H presented a review of our seventh year which provoked a lot of discussion ...
John drew attention to the recent change in the MariaDB 10 .mysql_history
file format which means that any old .mysql_history
file is overwritten [he later found the following thread in the RedHat Bugzilla which suggests that the issue has been around for a while but is only cropping up as distros update to MariaDB 10].
Paul outlined the proposed development of the Bradford CVS websites and Alice and John offered to look at ways of supporting these developments.
David described how he had dealt with the arrival of an Excel file containing images dotted about among the data about the proposed location for a dig. The first step had been to create a proper spreadsheet of the data and identify, using GPS, the latitude and longitude of two points which could then be used as reference points for the remaining data.
Alice began by demonstrating using Apache Spark, an alternative to MapReduce with Hadoop, to analyse Leeds Road Traffic Accidents. Using the Scala shell, she read in the text file, created a Scala class, created an RDD (Resilient Distributed Dataset), cached it and then queried it to find the Pearson (linear) correlation between, for example, accidents with more than one casualty and the type of vehicle. It works faster because the data is held in memory and it is scalable. It can also query data held in other types of database including SQL. Since the latest version of Excel will link with Hadoop, it can be used to query Excel data.
Alice sent their apologies via Twitter as she was still in Kazakhstan time.
Brian asked about Swanky Paint and asked for help with hostapd which was no longer working as he expected.
John H began with a short demonstration of cleaning up digital transfers of LPs using the noise removal and repair effects of Audacity to remove noise and eliminate clicks from the transfer. He then did a presentation arguing that LyX outforms any other software in document production though there are a few uses cases for which it is not suitable.
Kriss and Shi demonstrated the Raspberry Pi 2. It is faster and more stable, the power issues have been fixed and it has four USB sockets. However, the separate composite socket has gone and it is obvious that more work needs to be done on the video drivers.
Alice first introduced the Star Wars API which claims to have ‘All the Star Wars data you've ever wanted’ and gives you a chance to try out with claim and then the Beyond PNR presentation which takes you through the ways in which data is handled by the airline industry and the governments who want to know who is travelling where. (Click to advance the slideshow.)
Alice brought in a North Paw haptic compass which he passed round. Worn on the ankle, it contains eight mobile vibrators each of which is turned on when it is the nearest one to north enabling the wearer gradually to learn the direction of north.
Alice talked about the past three years working for a company which supplies a lot of entertainment. Every evening they get a spike for ‘Game of thrones’ as people log in and a double spike for football matches where people leave during the interval.
After a period of general chat Brian talked about his visit to the BarCamp Manchester where he had given two talks and heard an interesting talk about building a house with straw bales; it needs to be rendered with lime and have stakes to support it.
After we had cut the cake John did a review of 2013–2014 suggesting, among other things, that people who had not already done so should take a look at the IT Stuff website.
This led into a discussion of security, passwords and the iCloud breach.
John H summarised his experiences of the Linux Foundation LFSx101: Introduction to Linux course.
David C reminded people not to forget that the function keys on their devices sometimes control whether hardware is or is not available for use.
Brian warned people that the permissions relating to SD cards have changed in KitKat.
David S celebrated Slackware’s 21st birthday with a slide presentation in which he pointed out that, among other things, it:
Without our regular note taker present, the minutes from June’s meeting is a little lacking. We spoke about Leeds Art Crawl, Flight Radar, Truecrypt, and secure VoIP whilst attempting to install Android on an EePC (and getting slightly further in doing so than WYLUG).
Brian presented a number of recent discoveries:
Shi brought in the first edition of Linux Voice.
John H did a brief history of MIME Types in response to a question at an earlier session and then
David B introduced the Manchester Space Programme using the slides which had been used at the 27 February 2014 launch. MADLAB has considerably expanded and Makerspace has moved to new premises.
Brian used recordMyDesktop to demonstrate his Gnome desktop with the Cairo Dock desktop interface, BitTorrent sync syncing all his devices, Gigolo, a GUI for remote servers, to demonstrate how fast the Raspberry Pi is accessing a 2TB drive, and creating and applying a password in KeyPassX.
Alice demonstrated how to download Tor; it is better to download it directly into your own user rather than from repos because the direct download gives you everything you need and is likely to be more up-to-date than the versions in repos. The download comes with a start-tor-browser
script to run. The Vidalia graphical controller is included in the package and acts as a control panel.
Alice introduced logstash, a tool for managing logs, parsing them and storing the results for later use, in their case to produce graphs using graphite; logstash
has good documentation. In response to a question, she also mentioned using splunk to find errors in logs.
Brian described his experiences at the Liverpool Ogg Camp from which he had just returned. His choice of accommodation in the Youth Hostel had not proved entirely satisfactory. Open Street Map had worked well and got him to the University Arts Building; most of the arranged speakers were not very interesting but reps from Canonical and Mozilla were there to show off Ubuntu Touch and Mozilla OS. He had met Graham Morrison from LinuxFormat and Ben Nuttall who organises the Manchester Raspberry Jam.
After we had cut the cake John H did a quick resumé of the events of the past year.
Brian told us ‘the things that don't go into the guides’ as far as using FreePBX on the Raspberry Pi is concerned, including:
John H demonstrated the very different approaches taken by two very different vector graphics programs, Inkscape and Xfig, by tackling the first two exercises in Inkscape: Guide to a Vector Drawing Program (Third Edition) in both programs.
Shi and Kriss demonstrated the Oculus Rift virtual reality headset with a number of brave souls taking up the challenge; their recording of the session is at copy.com.
We had a general discussion around installing UEFI secure boot and then looked at a couple of April Fool RFCs: RFC 1149 and RFC 1925.
We had an impromptu Show and Tell this month. Alice explained how the classical approach to scaling websites was no longer appropriate for websites serving many pages. The time taken to generate material from a database, render it and despatch it was typically 6-800ms. You could reduce the load where many of the requests were for the same data by adding a cache or squid proxy. But this could create further problems keeping the cache or proxy up-to-date.
Brian demonstrated SqueezePlayer, the Logitech version and BubbleUPnP running on a mobile ’phone to play/control a media centre.
Happy Birthday to us, and thanks (once again) to Andrea for the baking. Yum!
At last night's meeting we discussed OpenVPN, Truecrypt, Bitcoin and Tomboy Notes.
The slides from the talk on OpenVPN are available from Github, but probably don't make any sense on their own.. We covered the use-cases for OpenVPN, along with discussion on problems setting it up people had encountered and tricks and tips. We also quickly installed a server on the night, so hopefully people feel more comfortable setting it up now.
David Fisher and Jeff introduced HTML5, saying that it was estimated that HTML5 will only receive full approval in 2022 because W3C standards now require full compliance from two browsers.
Alice told the story of privacy and the Web. In the beginning, ownership was confined to a few with most people in serfdom; then mortgages allowed people to begin to own things. In computing, one started with the mainframe where you didn’t own anything; then people got PCs which allowed them to own the hardware but not the code; Linux allowed people to own the hardware, the code and the data. With Web 2.0 you once again don’t own the hardware or the code or even your data; with the cloud you don’t own the hardware. In future IPv6 will be able to be used as ID numbers.
History is a useful tool for helping us find out why we do what we do today. If it we’ren’t for Unix, there’d be no GNU/Linux.
We started with a demo of Google’s ChromeOS, (built from the recently released source), by both Dick and Wayne. we saw a machine boot up to a login screen that uses your googlemail details to get straight into a familiar Google Chrome browser. And that’s about it – for people that live on line.
Lorna Mitchell gave us a introduction to ‘web services’, and some idea about how to go about consuming them using PHP as your language of choice. This was run through of the talk she’s due to give at the PHP Barcelona Conference on the 30th/31st October. She can describe it better than I can….
John demonstrated Xfig which provoked some interest but also dislike of the interface.
Mike talked about FreeSWITCH, a rewrite of the Asterisk code which, when combined with a billing package, can provide an alternative. Currently people are restricted to Skype and Gizmo [no longer available] as there aren’t many subscribers to open systems or gateways between the different providers.
This month Bernard Czenkusz, of Skipole Networks gave us an introduction to the popular programming language Python
With the abscence of a speaker/presentation we went for a ’show and tell’ session with people spending roughly 5-10 mins showing the rest of us something good!
Martyn Ranyard talked about video in Linux.
David S gave a full length presentation on Digital photography: the free software perspective.
He started by pointing out that:
As part of the talk on Open Source Gaming, Richard used the presentation below to tell us about Oolite, a space sim game, inspired by Elite (http://oolite.org/).
John gave a fascinating talk. If you missed it, check out the handout: Updated 26th Aug 2010
David C welcomed people to the meeting and shared the The Cycle of Change.
David C welcomed people to the meeting noting that people continue to sign up; there are now about 30 people on the list. The monthly meeting on a Wednesday had ten people at its last meeting; the Friday pub meeting had six.