Early Computing #
- The process of programming computers with punch cards was because previously putting instructions in memory was unfathomable - there was barely any memory available
- Relays were initially used as the switches that were wired into logic gates
- Vacuum tubes soon replaced relays as the building blocks of the gates, but were expensive and would fail after repeated use (though they changed state much faster than relays)
- The transistor changed all of this and became the modern building block of computers
- Moore’s law - the number of transistors on a chip doubles every 18 months
- With an 8 bit processor for example, you can add 16 bit numbers, it just takes a lot more instructions/complexity
- If the hardware of one processor can do something another can’t, the other processor can just do it in software
- Clock speed determines how fast each instruction is being executed
- A microprocessor is just the consolidation of all the components that make up the CPU onto one chip
- 8086 released in 1976
- The first chip in the x86 architecture set
- All newer x86 chips support the old opcodes from the 8086
- 386 released in 1985 - 32 bit
- Note: the number of bits a processor is refers to how wide the data pathway as data flows through the computer. While a 32 bit processor can add 64 bit numbers, it cannot do it without multiple adds of the low and higher order bit sets, carries, and intermediate value stores
BASIC- the first major interpreted language
Von Neumann Architecture #
- Computers should use binary internally
- Instructions should be sequential in memory and allow for conditional jumps
- Both data and instructions are stored in memory
- Cores (processors and associated memory, etc.)
- Node (the collection of all cores that use shared memory )
Von Neumann Bottlenck #
- The early computers spend a ton of time fetching an instruction from memory and preparing to execute it
Transistors #
- Invented in 1947 at Bell Labs
- Originally made of a semiconducting slab of germanium
- Bill Shockley originally conceived of the idea
- Shockley Semi-conductor labs formed in Palo Alto - the first company in the Valley
- Bill Shockley was also a terrible person
Semi-conductors #
- Have 4 electrons in the other shell (half-full) but can be manipulated with impurities
Integrated Circuit #
- The whole chip is made of silicon and the electrical pathways are etched out