programming chelahmy

If you are using Github then  master is now known as main . Whatever you want to do with a master must now be referred to a main . If you search for this error message on the Internet then you will encounter with a lot of old discussions on how to set up your master properly which is probably not what you are looking for. The master  is your problem. Rename it to main . I wrote Git My Way about two years ago. Today I created another Github repository. I got this  "fatal: Couldn't find remote ref master"  error message when I wanted to sync the new repo for the first time with my notebook using the notes I wrote in the blog. All the discussions around the error message I found on the Internet were perplexing. Then I recalled that Github had renamed master to main  due to the master-slave connotation. We always have a master copy of a code, never a slave copy. Now suddenly a word context has been diminished for good. What is going to happen to the existing va...

I was reading Understanding mRNA COVID-19 Vaccines by the United States Centers of Disease Control and Prevention when it stunned me that living cell can be programmed in vivo . mRNA COVID-19 vaccines are produced by Pfizer and Moderna . I already knew what Ribonucleic acid (RNA) is. RNA is almost a half part of DNA the super-intelligent organic codes that manifest us. But I didn't know that they can produce messenger RNA (mRNA) which can instruct cells to do whatever they wanted. This is my understanding so far. mRNA vaccines instruct our cells to make a protein and then triggers antibodies to kill the protein. In the case of mRNA COVID-19 vaccines it will instruct our cells to make a part of the virus proteins which is harmless to our body but sufficient enough to trigger the antibodies. Later when the real virus enters our body the trained antibodies will kill it. mRNA is a new kind of medicinal system. An mRNA can be sequenced or programmed to instruct a cell to make all sort...

You will get the Forbidden error message when you try to access a folder which is not a part of Drupal. I got that error message when I created a subdomain which was pointing to a folder inside a Drupal installation. At first, I wasn't thinking about Drupal and I was looking for a solution in a wrong direction until I realized the Drupal's strict .htaccess . Then, I came across a Drupal Answer -  Make a folder inside the drupal installation public . The solution is that you need to configure Drupal .htaccess to ignore the sub-folder for the sub-domain. Add a rewrite condition to ignore the sub-folder somewhere near the rewrite rule for index.php : RewriteCond %{REQUEST_URI} !^/your-sub-folder/ ... RewriteRule ^ index.php [L] And since the sub-folder is being influenced by the Drupal rewrite rules so the sub-folder needs to have its own rewrite rules. Add the following .htaccess file to the sub-folder: <IfModule mod_rewrite.c> RewriteEngine on RewriteBase /your-sub...

A blockchain is a chronicle of signatures . Everyone can see the signatures but no one can afford to alter them. As a new block of signatures joins in as time passes the blockchain security as a whole becomes stronger. Blockchain is protected by public cryptography with no need of a central supervision. By design, altering any of the signature will be a very expensive undertaking. So expensive as comparable to the cost of breaking a vault of gold, which act of breaking in is much more expensive than the gold itself. All signatures are well-verified prior to being kept secured into a blockchain. Hence, all signatures in a blockchain can be trusted without requiring any third party verification. The principle of blockchain was made popular through the Bitcoin  whitepaper  by an illusive Satoshi Nakamoto . Even though the two words block and chain were never mentioned as one word in the whitepaper the essence of blockchain was described through out the document. The Bitcoin b...

Every data has a signature  which can be derived mathematically. All data of any size can be digested into fixed-size signatures. The signatures can be used to identify the data. Unique data has unique signature. Cryptographic hashing is a mathematical technique to hash or digest a data to reveal its signature. Digesting the same data always produce the same signature. Any minor change on the data will produce significantly different signature. A changed data is a different data. Data signature, hashing or digesting makes it possible for the data to be represented by its signature into a subsequent signing by combining it with one or more data signatures to produce a new signature representing a larger data set. Eventually, all data can be digested in chunks to produce a single signature. A signature can be verified by hashing the same data again which will produce the same signature. This introduces data signing-verification concept. In a communication between two parties, ...

Hackers have emotion. People says the Bitcoin blockchain is hacker-proof. No hacker has ever managed to hack even a bit of the Bitcoin blockchain since its inception in 2009. The cryptographic process was designed to be very expensive to reverse. So expensive that the total world wealth is not enough to pay for the work to reverse the process. Thus, hackers express their frustration by plaguing the Bitcoin blockchain with grafittis. They creates fake transactions embedded with grafittis. It is so fake that even miners cannot differentiate. Fake transactions do not compromise on the integrity of the blockchain. However, each of them adds long term memory cost to the miners machines. Fake transactions soothe hackers frustration against so many failed attempts to hack the blockchain. Graffiti in Transaction What is a fake transaction? Before we answer that question let us understand what a real transaction is. A real transaction produces new coins to addresses. The new coins may com...