Category Archives: Uncategorized

Uncategorized but very important

Simple WebSocket Test on the Server Side

WebSocket protocol is a suitable way to create a reliable two directional connection between a server and a client. WebSocket is using the same ports as HTTP/HTTPS protocols: 80 and 443. However very frequently WebSocket is not such transparent as HTTP and may be blocked by firewalls, proxy or antivirus applications. Anyway if multiple WebSocket… Read More »

Experimenting with ECB and CBC Ciphers of AES

The openssl help shows 2 groups ciphers with ECB (Electronic Code book) and CBC (Cipher Block Chaining) suffixes. For example aes-128-ecb and aes-128-cbc or aes-256-ecb and aes-256-cbc for AES (Advanced Encryption Standard) ciphers. In ECB mode input data is divided in blocks of the same length. Then every block will be encrypted with the same… Read More »

ssh login troubleshooting

Suddenly ssh remote control to some of Mac devices stopped working, because remote host identification of that Mac device had been changed on remote side. Generally it means that the remote host key does not match the host key currently saved in /var/root/.ssh/known_hosts file. In other words the ssh handshake failed because host key verification… Read More »

Uninstall TeamViewer Host from Mac mainly from terminal

I installed TeamViewer Host on Mac, used it and when tried to drug and drop TeamViewer Host to Trash the dialog “The item “TeamViewer Host” can’t be moved to the Trash because it’s open” was popped up. I did not find any option to quit TeamViewer Host from GUI, just I could minimize the TeamViewer… Read More »

Email Validation For Web Forms

Web response form with email validation looks more professional and help to protect from posting garbage entered in email email text field. Email validation is a hard problem and cannot guarantee 100% address authenticity. There is TCP Finger protocol, which can retrieve user information via email address and confirm that the email address is valid… Read More »

WordPress Again. Installation Guide.

Every time when I am applying WordPress I am googling for some installation details. I remember the whole procedure but always need to refresh some nuances. I am not doing this every day or ever every month and it is difficult to keep everything in memory. It takes time so I decided to create my… Read More »

Finally Apple Silicon

This post is continuation of “Mac OSX CPU Information. Terminal and Programmatically”. Finally I got device with Apple Silicon processor. Virtual so far. I want to buy physical one when both happen it will be available in store and enough money in my pocket or account or whatever. I hope it happens soon. # sysctl… Read More »

Python deals the cards

About 10 years ago I applied to software developer position and received the following coding exercise: Using Java/Python, please design and implement the classes for a card game (pick any game, Poker for example), which uses an ordered deck of cards, containing 52 cards divided in 13 ranks (A, 2, 3, 4, 5, 6, 7,… Read More »

Mac OSX CPU Information. Terminal and Programmatically.

Apple Silicon CPU is coming. As announced x86_64 application will be able to run on ARM Apple Silicon using Rosetta translation, however there is some exclusion for example Rosetta doesn’t translate Kernel extensions. I checked this Saturday at Costco, they still sell Intel based Mac only. I opened terminal on demo Macs and executed sysctl… Read More »