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.
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
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
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.
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.
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.
Shi brought some cakes, including a beautiful chocolate cake, to celebrate our ninth birthday.
As a result of questions by Ash at the previous meeting and John W at this one,
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,
We welcomed Ben, a Python programmer from Cambridge, who was on a working trip to West Yorkshire.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.