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 ...
For the first time ever, no-one had come prepared with anything. So we welcomed Brian from Spain, talked about youtube-dl and get_iplayer and watched the Stephen Bourne lecture about the Early days of Unix and the design of sh.
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].
There comes a time when small charities begin to think about a website. You need four things for a website:
The first annual Cantor Lecture, funded by the Vice-Chancellor of Bradford University, Brian Cantor, on similar lines to the series he had funded when he was Vice-Chancellor of York University, was given on 30 June 2015 by Prof. Sadie Creese, Professor of Cybersecurity at the Department of Computer Science, Oxford University where she has been since 2011; she was Professor and Director of e-Security at the University of Warwick’s International Digital Laboratory from 2007 and previously at QinetiQ. She is currently on a sabbatical.
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.
There’s one thing that should frighten everybody who uses a desktop or laptop computer or server, and that is disk failure. Your storage should be the only part of the computer that you really care about. If not backed up, the information on your disk can be irreplaceable: when it’s gone, it’s very probably gone for good. Yet your precious information is entrusted to one of the few components in a computer that can break down completely, without warning, or literally wear out.
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.
Just over four years ago, a group of developers who had become fed up with the slow pace of development of OpenOffice started an alternative project now managed by a German charitable foundation, the Document Foundation, to create a modern, and superior, alternative to Microsoft Office. They were gratified to receive support from major computer companies and many other developers who had become disillusioned with the slow pace of development of OpenOffice.
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.
Windows refused to boot? Hard drive failing? Got a ransom virus that won't let you use Windows? Then System Rescue may be what you need.
System rescue is a suite of utilities developed primarily by a team of French developers which will allow you to overcome most problems you may encounter in these and many areas. You can download it and burn it to a CD or, using
isohydrid first, to a USB stick.
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.
It is over 25 years since Richard Stallman set up the Free Software Foundation and Intel commissioned Michael Tiemann to write the first open source software and less than 25 years since Linus Torvalds issued the first version of Linux and Berkeley Systems Department issued the first version of Unix to run on PCs. Yet today, these operating systems dominate computing in super computers, space exploration, scientific computing, digital televisions, smartphones and Internet services and are gradually being taken up by motor vehicle manufacturers and the creators of household equipment and gadgets. Only on the desktop and in medical devices has free and open source software not made significant inroads.
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.
Businesses have lots of Customer Relations Management software to choose from; the voluntary sector has one, tailored for the needs of voluntary organisations from the outset. Unlike most similar software, it is not a free-standing program but runs as an extension to Drupal (for which it was originally designed), Joomla or Wordpress. Moreover, you can select the components of CiviCRM that you need. So you don’t have to burden yourself installing features that you are never likely to need.
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.
IT Stuff now has its own dedicated website where you can find full details of recent programmes.
David S celebrated Slackware’s 21st birthday with a slide presentation in which he pointed out that, among other things, it:
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
When Adobe created the PDF (Portable Document Format) in 1993, it was aimed at large companies who wanted to distribute documents without having to bother about whether those who received them had particular fonts on their computers. While the software to create a PDF was fairly complicated — and expensive, the software to read it was simple. In 2000 this software began to be given away free and in 2008 all the software became an open standard.
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.
To continue to use an old XP computer, it really needs at least 1Gb of RAM and a 20Gb hard drive. Linux doesn't need 1Gb; it can happily run in less than half that but, for Internet browsing, 1Gb is the recommended minimum if you want to avoid some websites slowing your machine to a crawl.
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.
Here are the answers to the quiz:
The MySQL database was one of the most successful free software projects of the 1990s; it became an indispensable part of many websites as the Internet grew not least because it became cross-platform over fifteen years ago. Today it provides the storage for many content management systems such as WordPress, Joomla and Drupal.
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.
After twelve and a half years, most of them as the most popular operating system in the world, Microsoft will be pulling the plug on Windows XP on 8 April 2014. There will be no more security updates, leaving those users who choose to connect to the Internet vulnerable. Though anti-virus programs will continue to work, they will not protect users from any security holes that cybercriminals discover and which Microsoft will no longer close through their monthly security updates.
Back when the world was younger, there used to be a saying: ‘A Yorkshireman is a Scotsman with the generosity taken away.’ Offensive sayings like that are thankfully rarer these days, but that one may have had a grain of truth. There's still a cultural reluctance, here in the West Riding, to spend hard-won cash on overheads like IT that benefit far-away corporations, particularly when one is volunteering one's own services for free to a community project.
If they use software for their accounts, many voluntary organisations will start off with a spreadsheet. These are perfectly adequate for many small organisations; my sister in law manages their church accounts entirely in a spreadsheet.
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.
A major headache for organisations that use Windows Active Directory but want to use certain non-Windows devices on their networks has been the limitations on integrating those devices into Active Directory. The arrival of Samba 4 removes these problems. However, getting here has been a long haul.
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.
The Raspberry Pi was the unexpected success story of 2012. Designed by a team led by Eben Upton, who as a tutor at Cambridge had become concerned about the poor computing skills of university applicants, and including David Braben, a veteran computer game designer, this credit card sized computer aims to put the fun back into computing.
With mobile becoming more and more important in internet-based outreach, it's good to think about your mobile web strategy. You are recommended to build websites capable of display on desktop, tablet and mobile devices; we call this responsive design, a design which responds to the size and capabilities of the screen being used.
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.
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.
David S gave a full length presentation on Digital photography: the free software perspective.
He started by pointing out that:
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.
Broadcast on: 29th August 2013 18:00 and 30th August 2013 13:30 BCB 106.6FM
Happy Birthday to us, and thanks (once again) to Andrea for the baking. Yum!
This months meeting we will be welcoming Andy Davidson Of Hurricane Electric to the LUG to give us all a primer on IPv6 and also for those of us that want to a practical example of what its all about. This kind of goes without saying but if you want to get the most out of it you might want to bring a laptop!
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….
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.
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
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).
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.
What's Actually New in HTML and What Isn't in it at all
Unsurprisingly, they often got the wrong end of the stick; misled by corporate PR hyping browser and platform capabilities with only indirect relationships to HTML5.
This talk attempts to clarify what HTML5 actually aims to do, what browsers can currently do with it, and what a wider range of software could potentially do with it.
The talk will identify the evolutionary and revolutionary differences between HTML5 and the current standards for HTML and XHTML. In so doing, it should enable both web developers and open source advocates to get a better grasp of the decisions and conflicts that lie before them.