Engineering and technology notes

Coulomb barrier – Wikipedia

Jovan Stosic August 26, 2018

The Coulomb barrier, named after Coulomb’s law, which is in turn named after physicist Charles-Augustin de Coulomb, is the energy barrier due to electrostatic interaction that two nuclei need to overcome so they can get close enough to undergo a nuclear reaction.

To overcome this barrier, nuclei have to collide at high velocities, so their kinetic energies drive them close enough for the strong interactionto take place and bind them together.

https://en.wikipedia.org/wiki/Coulomb_barrier

Mechanics of Flite – Disabling binlog_checksum for MySQL 5.5/5.6 master-master replication

Jovan Stosic August 21, 2018

Disabling Binlog_checksum for MySQL 5.5/5.6 Master-master Replication

Replicating from a newer major version to an older major version in MySQL (for example a 5.6 master and a 5.5 replica) is generally not recommended, but when upgrading a master-master replication topology it’s hard to avoid this scenario entirely. We ended up in this situation last week when upgrading the passive master of an active-passive master-master pair from 5.5 to 5.6. The primary replication flow was going from the active master (5.5) to the passive master (5.6) with no errors, but pt-heartbeat was running on the passive master, which led to a replication failure with this error on the active master:

Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: ‘Slave can not handle replication events with the checksum that master is configured to log; the first event ‘bin-log.002648’ at 4, the last event read from ‘/var/lib/mysqllogs/bin-log.002648’ at 120, the last byte read from ‘/var/lib/mysqllogs/bin-log.002648’ at 120.’

Why did this happen? Starting in MySQL 5.6.6, the new binlog_checksum option defaults to CRC32. Since that option did not exist in MySQL 5.5, the replica can’t handle the checksums coming from the master. Therefore I recommend setting binlog_checksum=NONE in my.cnf as part of the upgrade process for a master-master setup to avoid this error.

My fix was to run this on the passive master:

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set global binlog_checksum='NONE';

Then I added this to my.cnf so it would survive a restart:

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binlog_checksum=NONE

After that change was made I examined the binary log to confirm that it did not include anything other than pt-heartbeat activity, and then executed CHANGE MASTER on the active master to skip the checksummed events.

Once the other master is upgraded I can go back and consider changing binlog_checksum to CRC32.

Source: Mechanics of Flite – Disabling binlog_checksum for MySQL 5.5/5.6 master-master replication

Samsung LE-32M61B – 32″ LCD TV – widescreen – 720p – HDTV monitor

Jovan Stosic August 19, 2018

Product Description Samsung LE-32M61B – 32″ LCD TVProduct Type LCD TVDiagonal Size 32″ – widescreenDimensions (WxDxH) 80.4 cm x 25 cm x 62.3 cmWeight 19.2 kgColour BlackDigital Television Certification HDTV monitorResolution 1366 x 768Display Format 720pVideo Interface Component, composite, HDMI, S-Video, SCARTHDMI Ports Qty 1 port(s)PC Interface VGA (HD-15)Technology TFT active matrixImage Aspect Ratio 16:9Analogue TV Tuner PAL, SECAMFeatures Auto noise reduction, DNIe (Digital Natural Image engine)Sound Output Mode StereoSpeaker System 2 speakersSound Effects SRS TruSurround XTStereo Reception System NICAM, A2GENERALProduct Type 32″ LCD TVDigital Television Certification HDTV monitorVideo Interface Component, composite, HDMI, S-Video, SCARTHDMI Ports Qty 1 port(s)PC Interface VGA (HD-15)Width 80.4 cmDepth 25 cmHeight 62.3 cmWeight 19.2 kgEnclosure Colour BlackDISPLAYDiagonal Size 32″ – widescreenTechnology TFT active matrixResolution 1366 x 768Display Format 720pImage Aspect Ratio 16:9Dynamic Contrast Ratio 5000:1Brightness 500 cd/m2Viewing Angle 178 degreesViewing Angle (Vertical) 178 degreesColour Temperature Control YesFeatures Auto noise reduction, DNIe (Digital Natural Image engine)TV TUNERAnalogue TV Tuner PAL, SECAMReception System PAL, SECAM-I, SECAM-D, SECAM-B, SECAM-K, SECAM-G, SECAM-LStereo Reception System NICAM, A2VIDEO FEATURESHDTV Ready Built-inTeletext YesTeletext Memory 1000 pagesAUDIO SYSTEMSound Output Mode StereoSurround Mode Built-inSound Effects SRS TruSurround XTEqualiser Yes (5-band)Speakers Included 2 speakersOutput Power / Total 20 WattSpeaker(s) 2 x right/left channel speaker – built-in – 10 WattCONNECTIONSConnector Type 1 x VGA input ( 15 PIN HD D-Sub (HD-15) )1 x component video input ( RCA phono x 3 )1 x HDMI1 x headphones1 x composite video input ( RCA phono )1 x S-Video input ( 4 PIN mini-DIN )2 x SCART ( 21 PIN SCART )1 x composite video output ( RCA phono )1 x antennaMISCELLANEOUSIncluded Accessories LCD TV standPOWERPower Consumption Stand by / Sleep 3 WattPower Consumption Operational 170 WattDIMENSIONS & WEIGHT DETAILSDimensions & Weight Details TV set – 80.4 cm x 11.3 cm x 56.4 cmTV set with stand – 80.4 cm x 25 cm x 62.3 cm x 19.2 kg
http://www.backoffice.be/prod_uk/Samsung/le-32m61b_samsung_le-32m61b_32_dquote_lcd_tv_widescreen_720p.asp