[CrashCourse CS] #19 Memory & Storage

In general, computer memory is non-permanent. It is called volatile memory.

Storage is different from memory.
Any data written to storage does not change until it is overwritten even after power goes out. It is non-volatile.

Development of Computer Memory

1. Paper punch cards, punched paper tape - the eariliest computer storage

2. Delay Line Memory(1944) -> Megnetostrictive Delay Lines

3. Magnetic Core Memory

4. Magnetic Tape(1951)

5. Magnetic Drum Memory(1950-1960)

6. Hard Disk Drives(HDD)

   • Floppy disk

7. Optical Storage

   • Laser Disk(1972) -> Compact Disk(CD), DVD

8. Solid State (use integrated circuits)

   • USB stick, Solid State Drives(SSD)

How does an integrated circuit store memory?

To greatly oversimplify, they use the classic gates we saw earlier in this series, but with a type of transistor that has resistive material around it, holding the charge "in place" unless a stronger charge overwrites it.

Memory Hierarchy of a machine

The faster the memory, the more expensive the cost.
Using various types of memory to acheive a balance between cost and speed.

• Small amount of fast/expensive memory, big amount of slow/cheap memory.

Vocabulary

• volatile - 휘발성의, 불안한, 변덕스러운
• ubiquitous - 흔한
• coaster - 컵받침

Thoughts

요즘 애들은 플로피 디스크를 한번도 보지 못해서 저장버튼 아이콘이라고만 알고 있다던데... 세상이 변하는 속도가 점점 더 빨라진다.