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Migrate/Upgrade Ubuntu 18.04 LTS (Bionic Beaver) GNU/Linux from 32 bit to 64 bit HowTo

Submitted by Ewan on 

Sorry, no more upgrades for this system
There will not be any further Ubuntu releases for this system's 'i386' architecture. 
Updates for Ubuntu 18.04 will continue until April 2023.

This guide is for you if you've seen the above message and you want to upgrade your Ubuntu system to 20.04 LTS.

This brief HOWTO shows how to take a working 32 bit 18.04 installation and convert it into a 64 bit system. You will be able to keep all your programs, settings and data. Once converted to 64 bit you can plan the upgrade to 20.04 LTS.

Classifications: 
Ubuntu

Use EEPROM and other memory on Arduino with wear leveling

Submitted by Ewan on

Here is an Arduino library allowing you to write to all flash or EEPROM space with wear leveling. The library already supports multiple memory types (internal EEPROM, I2C and SPI) and can be extended very easily to support others. The memory space can be used as a space to store configuration data with wear leveling, or to read and write (at the same time) sensor data filling the whole memory space efficiently.

Classifications: 
Arduino

Add another hardware serial port to Arduino (MAX3100 library)

Submitted by Ewan on

A complete Arduino library for the MAX3100 serial UART/USART chip can be downloaded below. There have been many requests for an Arduino library for the MAX3100 external serial USART (UART) chip from Maxim Integrated. As an example of the minor changes needed to use the MAX3100's serial port instead of (or in addition to) the built in serial port, here is some sample code (note the lower case 's' is the only change needed to use the new serial port).

Classifications: 
Arduino

SN74HC595 shift register simulation directly in Arduino

Submitted by Ewan on

There exists little practical information assisting with the experimentation of '595 shift registers.  This article and below Arduino sketch aim to address this vacuum.  The sketch simulates one or more (chained) 595 shift registers on the serial monitor while simultaneously driving the IC or ICs via the Arduino's pins.  This allows concurrent theoretical and practical experimentation with the 74HC595 first-in-first-out (FIFO) shift register family.

Classifications: 
Arduino

Presenting Ordnance Survey Meridian 2 data in QGIS

Submitted by Ewan on

Chelmsford, Essex 1:25,000 Meridian 2 QGIS
Romford, London 1:55,000 Meridian 2 QGIS
Purfleet, Essex 1:90,000 Meridian 2 QGIS

Below are QGIS QML stylesheets for OS OpenData Meridian 2 layers.  Ordnance Survey data has been available for a while for download as OS OpenData.  Also provided are SLDs for ESRI.  However these SLDs do not import correctly into QGIS.

 
Classifications: 
Geospatial
Places: 
UK

Large file synchronization

Submitted by Ewan on

Efficiently synchronize copies of a large sparse file locally. I deal with a large amount of large sparse files because of virtualization and other technologies. Because of their size, often a small number of blocks have data and, of these, a small number of blocks are changed and need to be backed up. Using a log-based (snapshotting) file system on USB 2 as a backup device, I only want to write blocks if absolutely necessary.

So what's the solution?  Some simple custom code that

  1. checks that both file sizes are identical;
  2. verifies that some metadata has changed (i.e time stamp, permissions or owner/group);
  3. reads both files block-by-block;
  4. writes only changed blocks to the destination file, and
  5. updates any changed metadata.
Classifications: 
C
GNU/Linux

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