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I write, therefore I am

With this variation on a famous statement by the philosopher Descartes, I would like to express that the act of writing about what happens in my life is important to me.

Sunday, December 1, 2024

Advent of Code

Yesterday, I made some preperations to join Advent of Code this year and try to get up at six in the morning every day till Christmas. I am going to use the literature programming with MarkDownC again. My progress can be followed in the repository AdventOfCode2024. Some people on the leader board:

Going into the city

I first went to the Media Markt show where I came across a PNY 512GB Attaché 4 USB 3.1 flash drive for just € 17.99. I could not resist the offer and decided to buy it. (The other product for which I came to the shop, happened much cheaper than I had expected.) Next, I went to bookshop Broekhuis where at 15:23:47, I bought the book Ooggetuigen: bezoekers vertellen over de collectie van het Bonnefanten written by Maria Barnas, Abdelkader Benali, and Sarah van Binsbergen, written in Dutch, and published by Bodosz Uitgevers in 2020, ISBN:9789082313116, for € 8.95. From there, I went to Rijksmuseum Twenthe, which had an open day with free entry. I first went to see the exhibition Chasing The Dot again and I sat for some time in the installation Chasing The Dot. I took some pictures of the books of Philip Vermeulen that were on display. I noticed that some had been moved. I looked around the back of the museum that was closed the last time we were there. I did not find the Falaises près de Pourville painting by Monet. It is possible that it has been loaned for an exhibition. I also came across the Beam Waver work by David Scheidler that is part of the exhibition Gogbot x RMT. I missed the two times before I saw this exhibition because it is a bit in a corner where it was not visible. I also saw that the exhibition PLANETART ARCHIVES X Kees de Groot 1978-2003 had been removed. They were selling posters and books at strongly reduced prices. I bought a poster of Falaises près de Pourville for one Euro.

Saturday, November 30, 2024

Link

Wednesday, November 27, 2024

Laurie Langenbach

I finished reading the book Brieven, dagboeken en een geheime liefde by Laurie Langenbach, which I started reading on September 26, the day I bought it. The book is part of a large series of (auto)biographic books. The book contains a short biography, a collection of letters and diaries, and the novel Geheime Liefde (Dutch for Secret Love) by Laurie Langenbach. The novel was about her being secretly in love with the Dutch chess player Jan Timman. She did not mention his name in the novel, her debut novel, but he was quickly identified after the novel was published. The novel did not receive good reviews. There are good reasons that this was due to it strong autobiographic content written by a young woman talking openly about sexuality. I found it an interesting read and making me want to read more from her. She wrote a lot of articles for various underground and mainstream magazines. I have not found a list of everything she wrote.

Sunday, November 24, 2024

Into the city

At the start of the afternoon, I went to the main venue of The Overkill Festival. It was rather quiet and I sat on one of the tables and worked a bit on this website. I also listened a bit to the SickFem “Having fun with synthesizers” workshop. I walked through the city because I wanted to look for something in a shop. I did find it, but there was a long waiting line, and I decided to come back another time or order it from the webshop. It has been a long time ago that I walked through the city center on a Sunday, but I felt it was really busy. Maybe it was due to high temperature of today, which really exception when compared with the low temperatures that we had last week. Maybe it caused by Storm Bert that is causing trouble in Ireland and United Kingdom. At Twenthe Airport has gone up to 17.4° Celsius, which breaks the previous record of 13.9° on this date in 1951.

I went to Concordia where I first looked at some people playing with the Joystick. Next, I talked a bit with Kira Fröse before I listed to the artist talk of Marthe Zink and her. Some people say that art should speak for itself, but it is my experience that when artist talk about their work and how they create their works, it makes you look at the works with a different eye and it often increases your appreciation. I had not realized that combinations of the works by both artist had been placed in circle shaped spots when watched from the correct location and that the colour of the spots was related to the works, often a colour found in both works. I really enjoyed the artist talk which was organized as a talk between the two artists and the organizer.

On the way home, I saw some impressive clouds in the sky, and I took the picture shown below.

Sunday, November 23, 2024

The Overkill Festival: Day three

During the second half of the afternoon, I joined the Consensual Hacking workshop by Melanie Hoff, which due to number of participants became more of a presentation about consent. Only after the workshop, some people sat together to some 'real' consensual hacking, where, if I understand correcly, Melanie allowed others to log into a laptop through ssh. I had to go home for dinner.

In the evening, I went again to the main venue, where I sat at one of the tables and talked with some of the other participants, while in the background listening to the music program. At the end of the evening, I went to the Sick&Sexy short films program with films selected by Menelas Siafakas. It was in a small screening room with fifthy seats, which (almost) filled-up completely. The following short films were screened:

It was an interesting experience to watch these short films together with other participants from the festival.

Friday, November 22, 2024

The Overkill Festival: Playfull Friday

There was some snow during the night. It did cover more than last Wednesday. In our garden the ground was not totally covered. The snow was already melting, causing waterdrops to fall from the trees. From what I saw on some roads, it looked like the snow did fully cover the grount. I arrived a little early at Het Vestzaktheater (Dutch for 'the vest pocket theater') for 'Playful Friday.' This year the theme is 'Radical Joy Resistance.'

At 10:16, as the opening of the day, lead by Zuraida Buter, who also acted as the curator, we stated to play with Play-Doh creating a sculpture named 'Joy' on the floor. It would stay there for the whole day.

At 10:30, Helen Kwok and Chad Toprak with a live connection from Melbourne showed things related to the theme: Sites of Resistance: A Walk Through Narm (Melbourne). It is 37°C there. They showed how people connected ribbons to the Evan Walker Bridge to show their solidariy with the people in Gaza. While walking through the city they showed places where protests and rallies were held and where playful activities were organized. They also showed pictures of these events and activities. Really an interesting way to give a talk from the other side of the world.

At 11:38, Jugar Jueguitos and Resistència VideoLúdica gave a workshop about Downpour game creation app. They are from Catalonia and Galicia, two surpressed cultures within Spain. With Downpour it is possible to create simple games without having to write code. That is why they have been using it for developing games.

After the lunch break, at 13:37, Nathalie Lawhead (Website, blog) gave the presentation A Tiny Talk About Tiny Tools. The started to talk about some old tools:

This gave her inspiration when creating The Electric Zine Maker. It has very strange tools and tools within tools. No tool is useless. She mentioned some other little tools: She likes these tools because you can export the result to a single HTML file that, for example, can be intergrated in Unreal Engine. She has used this in several of her games. Interesting resources for creating games are:

At about 14:10, due to some technical problems, Aran Koning gave the talk sok-Worlds, sokpop and other sok-stories. He is one of the four members of the sokpop collective and he created sok-worlds, a tool to create worlds with pictures and text. He showed us some sok-worlds, among some favourites: Crousant Moon, Dysphonia and Bart's Zoo. He then continued his talk by walking through 'boring world 10' by arni.

Next, Afra Willems gave the presentation Polished vs 'Primitive' - Resistance through multilingual visual styles. She told that she was surprised when she heard that the graphics of the game Thunderbird Strike by Elizabeth LaPensée was judged as unprofessional by game critics. She noted that these critics use words like sophisticated, polished, and high-end to describe the graphics of games. Is that what makes it professional. The mainstream style is technology oriented. She felt that this was an example of colonial ideas with respect to visual styles. She mentioned some quotes from the books Monolingualism of the Other or, The Prosthesis of Origin by Jacques Derrida and Black Skin, White Masks by Frantz Fanon about the surpressed and the language used by the oppressor. She mentioned three non-mainstream games that dealt in a different way:

(The above summary was based on notes I made during the presentation. I am to blame if I have mispresented her intentions.)

The next talk, (re-)Act through Playful Resistance in Digital Spaces was given by Jisoo Lim 임지수. The notes I took:

Around 16:15, Claire Kwong gave her presentation Prototyping with Touch and Intimacy. where she spoke about her games which encourage people to move and touch. She askes some people from the public to play her earlier games. She explained how she arrived at her game Between. She also asked the public for ideas for games that encourage people to touch each other.

The program ended with Pablo F. Quarta playing the game The Quiet Year with the audience.

The Overkill Festival: Second evening

In the evening, I went to the main exhibition room again. There I:played the following games: I looked at Casual Games for Protestors. Then I waited for the music performance AV set by Jim Zweerts. I sat on the ground, closed my eyes and got into a kind of meditative state during the performance. Below, a picture I took during the performance.

Thursday, November 21, 2024

Sauerkraut

This evening, we had our first home made sauerkraut that Conny had made from savoy cabbage and white pointed cabbage, which we have received in the harvest of Herenboeren Usseler Es. It tasted nice. So, it was quite a succesful attempt to make home made sauerkraut.

The Overkill Festival: Opening night

In the evening, I went to the opening evening of The Overkill Festival. It was held again at a different location than last year. The main location is at The Performance Factory. There I saw the following works: Around ten, I walked to the Black Brick location, where I saw:

Link

Wednesday, November 20, 2024

Snow

This afternoon, it snowed again and this time stayed on the grass and on cars. I estimate that at least 1cm of snow fell. The snow that stayed did not melt away in the evening, like it did yesterday.

Link

Tuesday, November 19, 2024

Wet snow

This afternoon, for some hourse there was wet snow falling from the sky. While it was snowing, some of it stayed on the grass a bit Still would not count this as snow. During the period it snowed, the temperature dropped to almost zero degrees Celcius.

Sunday, November 17, 2024

Cooperative, polling operating system

I have been thinking about a tiny cooperative and polling real-time operating system that works with static, single instance tasks. ESP-IDF is based on FreeTROS, a real-time operating system for embedded devives. Although FreeTROS is called real-time, it has some dynamic behaviour due to dynamic memory allocation and interrupts. Nowadays, many peripherals are connected through serial communication busses, such as SPI, I2C, and I2S, where there are often multiple slave peripherals are connected on a bus. These peripherals often have complex operating modes that can be adjusted through control registers, and possibly also complex behaviour patterns. This has an impact on the real-time behaviour of microcontrollers that communicate with these peripherals. If you do not want to use interrupts, it means you have to use polling to see if an interaction with a peripheral has completed. If you develop an application that interacts with several peripherals, it is logical to have some kind of layering in more device oriented tasks, coordinating tasks, and more high-level tasks. If you do not use operating system like functions like queues, this results in tasks polling the completing of lower-level tasks. To avoid excessive polling, which takes a lot of resources, I have been thinking about a number of queue based approaches to avoid polling. Tasks often make use of finite-state machines, which are usually implemented with case-statements. If these are not compiled to branch tables they performance is lineair to the number of cases. To work around this, one could use functions for each of the states and cause the right function to be called for each state. This does match with the idea of tasks. I have started writing some code as an experiment: TinyCoPoOS.c. I also have been thinking about program generating the code for all the functions given a tasks declaration.

Planting fruit trees

In the afternoon, I helped a bit with the planting of fruit trees at Herenboeren Usseler Es. When I arrived the others just were taking a break, because some of them already started at nine in the morning. I mostly dug holes at the places where a tree had to be planted. Twice we had some rain. The first time with some hail and at 14:30, there was a rainbow. I am looking forwards how the trees are going to grow in the coming years.

Saturday, November 16, 2024

Harvest

Below a picture of the harvest (except for the 2 kilogram potatoes) that we received this morning from Herenboeren Usseler Es. (What you receive depends on how many 'mouths' you are paying for and personsl choices you make.)

The picture shows:

In the evening, I made some stamppot with the lacinato kale, two small red unions, a yellow bell pepper and some sauerkraut bacon. Conny made a salad with the outer leaves of the two red chicories.

Friday, November 15, 2024

Book

At 17:05:15, I bought the book HETHE BESTE VAN OF WIM T. SCHIPPERS written by Harry Ruhé in Dutch and English, and published by Centraal Museum in 1997, ISBN:9789073285446, from bookshop Broekhuis for € 45.00. This is a bilingual edition where the Dutch text is printed in red and the English text in green on top of each other. To read the text a transparent green and red sheet is provided in the front of the book that you have to put over the text. This book is the catalogue of an exhibition of the same name.

Thursday, November 14, 2024

Exhibitions

After work, I went into the city where I visited the exhibitions at Concordia. I saw the following exhibitions:

Monday, November 11, 2024

Links

Sunday, November 10, 2024

Wijlre

On the way Wijlre Conny and I stopped at the Netherlands American Cemetery and Memorial located in the village of Margraten and waled around the cemetery. We thought about the many soldiers that died during the liberation of Europe from the German occupation and how this relates to the current war in the east of Europe. We did like the design of the chapel with the window on the side.

Close to noon, we arrived at Kasteel Wijlre Estate for the exhibition Maintaining Its Spirit: Collection Marlies & Jo Eyck. I found the following works noteworthy:

We also saw the exhibition Growing Poetics by Thierry Oussou. We in particular liked the La Poessie in one of the rooms in the attic that he had filled with branches he found on the estate.

On the way home we stopt at the McDonalds in Drosten were we ordered two McPlant meals consisting of a plant based burger with french fries and a cola. This is at least the third time I visited this McDonalds. I visited it on Saturday, September 22, 2018 with Andy and on Friday, July 29, 2010 with Li-Xia.

Saturday, November 9, 2024

Bonnefanten Museum

Conny and I visited the Bonnefanten Museum in Maastricht. We first went to see the exhibition Maintaining Its Spirit: Collection Marlies & Jo Eyck at Bonnefanten. I found the following works noteworthy to mention:

From the exhibition Stanley Donwood and Thom Yorke: Maps of the New World I liked:

From the exhibition Małgorzata Mirga-Tas: This is not the end of the road, a solo exhibition with works by Małgorzata Mirga-Tas, I found the following works to be noteworthy:

From the exhbition Dream On, I found the following works noteworthy:

From the exhibition Collection Neutelings, I found the following painting noteworthy:

From the exhibition Truly Wicked: The Seven Deadly Sins visualised, I found the following works noteworthy (I was getting a bit tired and filled with images):

Furthermore, we walked through Studio Rossi with design of the museum building and walked around The Shooting at Watou by Folkert de Jong.

Maastricht

After we visited the museum, we walked through Maastricht taking some pictures. We brought a short visit to the bookshop Boekhandel Dominicanen, which I visited before on Sunday, July 21, 2019. It was already dark, but we took some pictures from the Sint Servaasbrug (a bridge over the Meuse river) before went to the Indonesian restaurant KapuláGa were we had the Kakanda rice table, which existsed of yellow yice, daging balado, rendang, smoor, ayam pedas, ayam opor, sate ayam, sambal goreng udang, tempe, poached egg, sayur lodeh, seasonal vegetables, gado gado, atjar, seroendeng, roedjak. We had some strawberry ice as an desert. We were very satisfied with the dinner.

Thursday, November 7, 2024

Cubes from Sheet: 11 by 11

I have this feeling that there are solutions for all cubes from a sheet problems, where at least one piece can be placed into, exists where at most twelve squares are unused for cubes. In the past weeke, I have been searching for counter examples. The program that I used, took a long time to find a solution with less than thirtheen unused squares for a square of eleven by eleven squares. Yesterday, I modified my Exact Cover program to also support positions with multiple vectors. This is a generalization of the Exact Cover problem. The multiple positions are needed to restrict the number of unused squares to an exact number. When I tried this program on the elven by elven square with seven unused squares, it found some solutions within half an hour. The first solution it found was represented as (on a single line):

S0_1_2_13_14_15|S3_4_5_16_17_18|S6_7_8_19_20_21|e9|e10|E11_12_23_24_25_36|E22_33_34_35_46_47|W44_45_56_57_68_69|W55_66_67_78_79_90|E77_88_89_100_111_112|e99|e110|D31_32_40_41_42_52|e30|W43_53_54_63_64_74|W65_75_76_85_86_96|E87_97_98_108_118_119|e109|e120|A28_29_38_39_50_61|Z26_27_37_48_58_59|S51_62_72_73_83_94|S49_60_70_71_81_92|K80_91_101_102_103_113|A82_93_104_105_114_115|A84_95_106_107_116_117|

This evening, I checked this solution and made the following drawing of it: 

    +--+--+--+--+--+--+--+--+--+--+--+
    |        |        |        |##|##|
    +--+--+  +--+--+  +--+--+  +--+--+
    |     |        |        |        |
    +--+  +--+--+--+--+--+--+--+--+--+
    |  |        |     |     |##|     |
    +  +--+--+  +  +--+  +--+--+  +--+
    |        |  |  |     |        |  |
    +--+--+  +--+  +--+  +--+  +--+  +
    |     |     |  |  |  |  |  |     |
    +--+  +--+--+  +  +  +  +--+  +--+
    |  |     |     |  |  |  |     |  |
    +  +--+  +--+--+  +--+  +  +--+  +
    |     |     |     |     |  |     |
    +--+  +--+--+  +--+  +--+--+  +--+
    |  |     |  |  |  |  |  |     |  |
    +  +--+  +  +  +  +  +  +  +--+  +
    |     |  |  |  |  |  |  |  |     |
    +--+  +--+  +--+  +--+  +--+  +--+
    |##|  |        |     |     |  |##|
    +--+  +--+  +--+  +--+  +--+  +--+
    |##|     |  |     |     |     |##|
    +--+--+--+--+--+--+--+--+--+--+--+

I plan to refactor the code of my Exact Cover program such that it can be more easily be called from the program finding solutions for the Cubes from Sheet problems.

Tuesday, November 5, 2024

Book

At 18:40, I bought the book Prospects 2021: Mondriaan Fonds toont talent edited by Mirjam Beerman, written in Dutch, and published by Het Mondriaan Fonds in June 2021 from thrift store Het Goed for € 1.00. Before I there, I went to thrift store Rataplan. Although it seems they have more books there, I get the impression that they sell less books. These trift stores are for profit shops.

Link

Sunday, November 3, 2024

Links

Saturday, November 2, 2024

Colourful harvest

We got a rather colourful harvest from Herenboeren Usselere Es and I took a picture of a part of the harvest.

In this picture there are: a small puprple cauliflower, a romanesco broccoli, a fennel, two red cabbages, a green and a orange pumpkin, and a leaf of curly kale.

Link

Friday, November 1, 2024

63 years

I was born on Wednesday, November 1, 1961 at 9:45 in the morning (CET). That means that today, I will be 63 years according to the calendar and 23011 days old. But how old am I really? The tropical year, the time that it takes for the seasons to return, is said to be 365 days, 5 hours, 48 minutes, and 45.19 seconds. Yesterday, around 15:56:26 in the afternoon, it was 63 tropical years since I was born. But the tropical year is shorter than the sidereal year, the time taken by the Earth to orbit the Sun once with respect to the fixed stars, namely 365 days, 6 hours, 9 minutes, and 9.76 seconds. That means that, today at 13:22:14 it will be 63 sidereal years after I was born. The average anomalistic year, the time taken for the Earth to complete one revolution with respect to its apsides, is 365 days, 6 hours, 13 minutes, and 52.6 seconds. That means that, today around 18:19:13 it will be 63 average anomalistic years since I was born.

Double declaration?

I have been using the C progamming language (and later C++) for more than 34 years, but today I wrote something, I cannot remember having written before and it looks like a 'double' declaration of a variable: 
extern int counter;
int counter = 0;
I am big fan of encapsulation and I like clean include files that hide implementation details that are not necessary for the users of the functions given in the header file. The implementation for a certain header file depended on a global counter that I did not want to include in the header file itself, but it needed to be incremented somewhere else and initialized to zero. So, I wrote in that other location, the main file (containing the main function): 
extern int counter = 0;
And this resulted in a compile error, because you are not allowed to initialize a variable that is declared extern. Next, I changed the line into: 
int counter = 0;
Now, I got a linking error saying that the other external definition (in the C file implementing the header file that relied on the counter variable) was not defined anywhere. This is because although it is defined in the main file, it was not defined as extern and thus not visible on the outside and thus becoming invisible for the linker that combines all the separately compiled C programs into one executable. It dawned on me that if I would have placed the extern declaration in the header file, it would have worked because then during the compilation of both C programs it would have been defined as extern and in the main program I still would have been able to initialize it. Although it is not common to see a 'double' declaration in a C file, like the above, and even looks a bit confusing, it is actually somthing that is done all the time, because the C preprocessor put both declarations into the intermediate file that is compiled by the actual compiler.

Links

Thursday, October 31, 2024

Book

At 17:25, I received the book jurrian van den berg: verzamelaar van dingen written and illustrated by Linda Rusconi in Dutch and published by Lecturis in November 2024, ISBN:9789462265271, from the Lecturis webshop for € 40.00.

Sunday, October 27, 2024

ESP32 I²C without interupts

In some bare metal embedded solutions you do not want to make use of interupts, because they potentially could introduce unpredictable behaviour. If you want to do this for the ESP32 it usually means that you cannot the high-level parts of the ESP-IDF because they are based on FreeRTOS that uses interupts. The implementation of the I²C driver makes use of interupts. The interupt handler is the function i2c_master_isr_handler_default in the file i2c_master.c. In this function i2c_ll_get_intr_mask is used to get the information about the interupt being raised and the function i2c_ll_clear_intr_mask is called to clear the bits. Before, in the function s_i2c_transaction_start, the function i2c_ll_enable_intr_mask is called with I2C_LL_MASTER_EVENT_INTR, which enables the interupts for: The I²C driver is a bit of an overkill for the most common use of the interface to communicate with slave periphials connected to the I²C bus, which usually consist of transfering packets of data not larger than FIFO send and receive buffers, which, according to the i2c_struct.h files, are 128 bytes in size. The I²C allows for eight commands to be processed in one run, which is enough for a combination of a write and read interaction, where you select a register in a periphial and read out its data. Each of the commands has a done flag (command_done field of the i2c_comd_reg_t). This can be used to see if an I²C sequence of commands has been completed by looking at the flag of the last command (usually a STOP or END command). But if some reason the execution of the sequence fails and this flag is not set, there is no way to know this, except than to conclude after a certain time-out periode that an error has occured. So, it seems at least if you do not want to resort to interupts. Although I do read otherwise on various forums on the internet, I wonder if it is possible to enable interupts and not install an interupt handler. Chapter 9 explains how the ESP32 has an interrupt matrix to allocate peripheral interupt sources to the two cores to be processed. In the function i2c_new_master_bus the interupt handler i2c_master_isr_handler_default is installed by calling the function esp_intr_alloc_intrstatus. The function is also given the address of the interupt status register and the constents of the irq field of the i2c_periph_signal for the specified I²C device. This value is defined in the i2c_periph.c file and is taken from the periph_interrput_t enumeration of periphial signals. The function esp_intr_alloc_intrstatus (defined in the file intr_alloc.c) tries to allocate one of the 32 interupt for periphials (at the designated core), and after having done some more initializations and bookkeeping calls the function esp_rom_route_intr_matrix to link the periphial to the interupt. If you do enable interupts for a certain periphial the contents of the matching INTERRUPT_COREx_SOURCE_y_MAP is used. For the ESP32-S3 the valid values for these registers are 0~5, 8~10, 12~14, 17~28, 30~31, which are all the values of the category 'Periphial' in table 9.2. However, the default value (on Reset) is 16, which is the number of the 'Internal' category 'Timer.2' interupt. Because a periphial interupt can be assigned to a particular core, it is logical that the value in the matrix of the other core is not changed. So, it seems that the value 16 is the value (or a value) to indicate that the periphial interupt is not processed for the given core.

Link

Saturday, October 26, 2024

Chasing The Dot

Conny and I went to Rijksmuseum Twenthe to see the exhibition Chasing The Dot with installations by Philip Vermeulen. We saw the following installations: The Chasing The Dot installation reminded me on The Brain Machine by Mitch Altman. It has a lot of flashing lights at various frequencies. Sometimes you start to see a dot. I think this is related to the fact that at the center of your retina there is a different concentration of rods and cones than in the other parts of the retina.

We also watched a short documentary about Philip Vermeulen and there also was a room with books and some (related) works. The works are:

Some of the books: Conny also took a picture of me when I was standing under a light in one of the dark rooms.

Next we saw the exhibition Gogbot x RMT (also called: The Tec Divide), which I already saw on Friday, September 13. We watched the works in the following order:

We also walked through the exhibition PLANETART ARCHIVES X Kees de Groot 1978-2003. At one of the tables, there was a booklet about Reset: Manifestatie over simulatie, animatie en games in 1998 that was organized by TARt. Maybe it was seen as a reset of the earlier TARt festivals, but it was a little different. Kees de Groot was one of the artist at this manifestation and the primary location was called 'Planet Art'. I never new about this 'connection' between the TARt festivals and GOGBOT. That manifestation did include games developed by students. Several GOGBOT festivals have included project by students as well.

Friday, October 25, 2024

19.0° Celsius

The temperature at Twenthe Airport has gone up to 19.0° Celsius, which breaks the previous record of 18.9° on this date in 1953.

Tuesday, October 22, 2024

Book

At 16:56, I bought the book On Anarchism written by Noam Chomsky in English and published by Penguin UK in 2013, ISBN:9780241969601, from thrift store Rataplan for € 0.50.

Verifying and documenting live-bootstrap

My project "Verifying and documenting live-bootstrap" is one the selected proposals eligible to receive a grant from NLnet Foundation in the April 2024 NGI Zero Core call, alongside 48 other exciting new projects. I have decided not to accept this grant, because I have lost interest in the project, having finished most of what I wanted to achieve and gave a presentation about it on September 29. I made an attempt to also run strace for the other supported CPU's, but failed to do so. I have created a page to present the results and give some background and history of the project as a kind of finalization of my investigations of the past years.

Monday, October 21, 2024

23,000 days

Today, it is 23,000 days ago that I was born. I decided to celebrate this special day by treat my colleagues on (small) cake. On Tuesday, January 25, 2022, I celebrated that I was 22,000 days old. On Sunday, 18 July 2027, I will be 24,000 days old.

Low-level SPI on ESP32-S3

I am reading Chapter 30 of ESP32-S3: Technical Reference Manual to understand how Low-level SPI works when using it in master mode, using 1-bit SPI, 4-line half-duplex mode, and CPU-controlled single transfer (no DMA), normal bit order, writing and/or reading at most 4 bytes (32 bits), only using DOUT and DIN and skipping CMD and ADDRESS (because we are using 1-bit SPI and there is no need to have those). My notes are:

Section 30.5.8.4 'Half-Duplex Communication (1/2/4/8-bit Mode)' explains how to set the registers for the desired SPI-usage. My notes:

The file spi_struct.h gives C struct definition for accessing the different parts of the registers. These are used in the file spi_ll.h. The following 'functions' can be of interest:

Note that the ports of the device that is being used, also need to be set.

Thursday, October 17, 2024

Links

Wednesday, October 16, 2024

Mushrooms on tree stump

This morning, just before leaving for work, I took some photographs in our backgarden of the mushrooms that appeared on the tree stump of the chestnut tree that we cut down two years ago. I have no idea what kind of mushroom it is, but I guess that it is a member of the family of polyporacae.

Monday, October 14, 2024

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