Updated: 2020-10-20


Systems: groups of components that cooperate to perform some function.


Phone as a Modem.


  • HCL fully compatible with JSON, JSON can be used as completely valid input to a system expecting HCL
  • another format: HOCON


bootstrapping usually refers to a self-starting process that is supposed to proceed without external input. get (oneself or something) into or out of a situation using existing resources.

A modal window is a child window that disables parent window

Progressive Disclosure

Progressive Disclosure is a concept in User Interface Design which advocates only presenting to the user the information they need when they need it.

Game Theory


  • John Nash: A Beautiful Mind


  • minimax search with alpha-beta pruning: discrete state space, perfect information, turn-based game like chess and checkers
  • expectimax optimization


NUMA(Non Uniform Memory Access)

NUMA architecture: it takes a different amount of time to access different parts of memory, i.e. memories are not created equal: some are local and some are remote. Each processor has a local memory with low latency and high bandwidth, while remote memory is slower to access.

Octet Stream

= bytestream


the property of certain operations in mathematics and computer science, that can be applied multiple times without changing the result beyond the initial application. e.g. HTTP GET


hypertext = text + hyperlinks + others

Hypertext Application Language: HAL


=named tuple

tebibyte vs terabyte

  • terabyte (TB): 10^12 or 1,000,000,000,000 bytes
  • tebibyte (TiB): 2^40 or 1,099,511,627,776 bytes, roughly 1TiB = 1.1TB

Law of Demeter

principle of least knowledge

Benford's law

also called the first-digit law, is an observation about the frequency distribution of leading digits in many real-life sets of numerical data. The law states that in many naturally occurring collections of numbers, the leading significant digit is likely to be small.

Conway's law

Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization's communication structure

Fake vs Mock

  • Fake: a lightweight implementation. It actually works, but not with full implementation and not for production.
  • Mock: used to make assertions; "given input X, return Y"