GA500

    In UNIX "Everything is a stream of bytes"* 
    became to a "Everything is a file"
    *) The UNIX-HATERS Handbook, 1994

Memory types in computer
------------------------

  I. Ancient computer: 
    1. volatile memory (SRAM, DRAM, needs power to operate)
    2. internal storage (HD, SSD) power independent, boot or load process needed before program is executed by CPU)
    3. external storage for backup and replication.
    
  II. Classical computer:
    Same, as I., but internal storage is M.2 (bypassing legacy interfaces: SATA, IDE). Usualy have system restore partition on internal storage. Sleep mode: need to boot after power was lost. Hibernate: dump RAM to M.2 and back to save accumulator energy.
    
  III. Innovative computer:
    Power independent memory. (HP's "memory-driven architecture" [1], 2017). No internal storage required. Still have bottleneck between processing and memory units.
    
  IV. Futuristic computer: Distributed computing integrated with memory.
    Neural design.

In classical approach (I.)
  + Everything is the stream of bytes [1].
  + String as number (usually long).
  + Dictionary as a pair of strings (key, value)
  + File as a record in a dictionary on storage memory, where key is a file name and value is a file body.
  + Variable as a file in volatile memory. (Body part is usualy short).

Variables
---------

Write:

  $ X=15
  
Read:

  echo $X

Links
-----

[1]. HP kills The Machine, repurposes design around conventional technologies

  http://www.extremetech.com/extreme
    /207897-hp-kills-the-machine-repurposes-design-
    around-conventional-technologies
    
[2]. Ryans Tutorials -- Bash Scripting Tutorial
  http://ryanstutorials.net/bash-scripting-tutorial/
  
[3]. Sh - the Bourne Shell 
  http://www.grymoire.com/Unix/Sh.html
