Side-by-side comparisons that explain the difference and when to choose each option.
An A record points a name at an IPv4 address; a CNAME makes a name an alias of another name. The rules, the apex restriction and when to use each.
IPv4's 32-bit addresses ran out; IPv6's 128-bit addresses do not. How the two differ in notation, headers, configuration, NAT and everyday administration.
TCP delivers every byte in order over a connection; UDP sends independent datagrams with no guarantees. What each costs and which protocols use which.
MD5 is broken, SHA-256 is the fast general-purpose hash, and bcrypt is a deliberately slow password hash. What each is for and which to use.
Symmetric encryption uses one shared key and is fast; asymmetric uses a public/private key pair and solves key exchange. Why real systems use both.
JSON for APIs and data exchange, YAML for hand-edited configuration, XML for documents and schema-heavy standards. Syntax, types, pitfalls and when to use each.
Which image format to use: JPEG for photos everywhere, PNG for lossless graphics, WebP and AVIF for smaller files on the modern web. Features compared.
A 15-year mortgage costs far less interest but has a much higher payment; a 30-year loan is cheaper monthly and more flexible. Worked $300,000 example.
Traditional IRAs give a tax break now and tax withdrawals later; Roth IRAs tax contributions now and withdrawals never. The marginal-rate rule, worked out.
Simple interest is paid on the original amount only; compound interest is also paid on past interest. The formulas, a $10,000 example and where each is used.