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1. User Case for Multiple User in OS

  • Multiple User in Household
  • Privacy
  • Personal and Work Separation
  • Guest Access
  • Software development

2. What’s the Right of Government Come from

In political philosophy. A foundational concept

Many theories:

  • Social Contract Theory: hypothetical and historical agreement between rulers and the ruled
  • Consenr of the Governed: is legitimate if it has the consent of the people it governs. Expressed through elections, refernda
  • Legal-Rational Authority: based on established laws and procedures
  • …

2.1. The minority obeys the majority?

In majoritarian systems, the majority’s preference may dominate policy and decision-making

  • Libreal democracy: embed protections for individual rights
  • Deliberative democracy: the decision should result from free, inclusive, reasoned debate rather than sheer majoritarian
  • Checks and Balance: offer protection to minority interest

2.2. The Bill of Right

Collective name for the first ten amendments to the US constitution. Ratified in 1791

  1. Freedom of speech, religion, press, assembly, petition
  2. Keep and bear arms. Giving citizens to resist a goverment
  3. Prohibit the goverment from forcing people to shelter soldiers in homes
  4. Guard againt unreasonable searchs and seizures.
  5. Protect against double jeopardy and self-incrimination
  6. Guarantee a fair and speedy trial to criminal defendants
  7. The right to a jury trial (陪审团审判)
  8. Against excessive fines and unusual punishment
  9. People have other rights more than the enumeration of certain right
  10. If power not delegated to the federal, then to the states or the people

3. How is the Nation Border Decided

Combination of historical, geographical, political and sometimes arbitrary reasons

  • Natural borders: rivers, mountain ranges, oceans
  • Treaties and agreements
  • Colonialism: drew border without regard for the ethnic, cultural and tribal boundaries. Evident in Africa
  • Ethnic and cultureal division
  • Post-war adjustment

4. What is NVME, Why Faster, Why 2280

Non-Volatile Memory Express

  • Protocal developed specially for SSD: NVME (Rather than AHCI in SATA)
  • Take advantage of Interface PCIE bus (rather than SATA)
  • Parallelism
  • Reduced latency
  • Optimized for NAND flash

4.1. Size

M2 form: 2280, 2242, 22is the width, 80/42 is the length

2.5 inch SATA

mSATA

U2: 2.5 inch NVME

4.2. Name of M2

Simply a naming convention standardized by the PCI-SIG

before M2, there is mSATA

5. How is Wafer Made

  1. Mining and refinement: extracted from sand, made up of silicon dioxide
  2. Purified silicon is converted into a form called polysilicon
  3. Growing silicon Ingot
    1. Polysilicon is melted, exceeding 1400 C
    2. Seed crystal is dipped into molten silicon
    3. Seed slowly withdrawn while rotating, form a cylindrical shape
  4. Slicing: Sliced into thin wafer using precision saw
  5. Polishing: polished to achieve a smooth and defect-free surface
  6. Cleaning

5.1. Silicon?

  • Easy to get
  • Semiconductor properties
  • Withstand high temperature
  • Ideal Energy bandgap

5.2. Chip?

Wafer can be substrate of IC

  • CPU, memory chip can be fabricated on wafer
  • Image sensor, CMOS, need specific steps optimized for light capture

Logic gate: silicon based IC using transistor, MOSFET

Not pure silicon: dopants are introduced for N type region and P type region

Maybe video can help better understand this topic

6. How Mole Developed

Formation:

  • Genetics
  • Sun exposure
  • Hormonal changes

Type: various shapes, sizes, colors, flat or raised, smooth or rough

Harmful?

  • Most are benign and no risk
    • Change in size, shape, color might be sign of cancer