The Bitcoin block chain had reached 85 gigabytes last week, so it was no longer practical to run a full node client on my laptop. A full node client verifies a transaction by checking earlier transactions all the way back to when the network first issued the funds used in the current transaction. To do this, it first has to download every block of transactions in the chain. The alternative is a client that uses simplified payment verification (SPV).

Bright House Networks does not support IPv6, so I use the the Hurricane Electric IPv6 Tunnel Broker service to reach the IPv6 Internet. Last Wednesday night, Netflix started showing an error message when I tried to play movies: “You seem to be using an unblocker or proxy. Please turn off any of these services and try again.” Netflix customer support first said my access was blocked because my IPv6 address came from a different state. I switched to a tunnel in my own state, but Netflix still blocked me.

I’ve been able to connect to an Acquia database before from MySQL Workbench 6.2.4 on OS X, but today I was getting an error:

Could not connect the SSH Tunnel

Authentication error, unhandled exception caught in tunnel manager, please refer to logs for details

To see the logs, go to Help » Show Log File. The relevant log file is wb.log, and the error message is

SSHException: Incompatible ssh peer (no acceptable kex algorithm)

I was trying to get a list of highest numbered records from an SQL database table. My first attempt used a GROUP BY and an aggregate function:

SELECT * FROM field_data
GROUP BY revision_id
HAVING delta = MAX(delta)

This means to only return records which contain the highest delta values their revision IDs. I know SELECT statements are only supposed to have fields which appear in the GROUP BY clause, but I tried it just in case. The HAVING filter had no effect. My second attempt used a join:

When I tried to use Airplay to make my TV a second display, the TV went blank. None of the mirroring options were shown in the Airplay menu. I called Apple support, but Airplay mysteriously started working during the call. Yesterday, the problem was back. I found the solution in an Apple support community post. There seems to be a bug in El Capitan that prevents Airplay from being used as a second display if there is an invalid login item.

I’m working with a MEAN app on Mac OS X El Capitan Version 10.11.3. Every time I restart the computer, the app crashes, saying, “Too many open files.” I have to run this command in the terminal to get the app to start:

ulimit -n 1024

I set up Dreamhost cron jobs to run drush cron for two different sites running Drupal 8.0.3. One of the cron jobs worked, but the other failed with a syntax error. Drupal 8 requires PHP 5.5.9 or later, and the default version of PHP for one of the sites was 5.4.42. Changing the default PHP version in .bash_profile and .bashrc did not fix the error.

Server 5.0.15 gets stuck configuring Xcode 7.2.1 unless Xcode is run at least once as root: https://forums.developer.apple.com/thread/34683.

If you add a private files directory after installing Drupal 8.0.3, you will get a warning on the status page saying it is not fully protected and to see https://www.drupal.org/SA-CORE-2013-003 for information about how to protect it with an .htaccess file. The message shows up even if the directory is not Web-accessible. Ignore it. The .htaccess file will be created automatically after caches are rebuilt.

Usenet used to be the Internet. The World Wide Web was announced on Usenet. But most ISPs no longer offer Usenet. Usenet has been replaced by Web forums (I include Facebook and Twitter in the definition of Web forums). Why?

Usenet lacks two things that Web forums have:

• Authentication
• Permanent archiving

The need for these two features is the reason Web forums have replaced Usenet.