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Crash Course Science Computer, Crash Course Science Computer - Coggle…
Crash Course Science Computer
1~10
Early Computing
abacus
Difference Machine
used to calculate polynomial
punch card
Mercury flows through the holes to create a circuit
Electric Computing
vacuum tube
transistor
relay
Boolean logic & logic gate
logic gate
And
Or
Not
XOr(Exclusive Or)
the advantage of binary: it's easy to be separated, even if som ele tric noise nearby.
representing number and letter with binary
byte: a byte is 8 bits
The 32 bits way to store number: 1 for the sign; 2~9 for the exponent, the remaining for the significand
The ALU(Arithmetic and Logic Unit):
arithmetic unit(for numberical operation)
full adder table
A + B + C -> carry bit & sum bit (1st. use half adder table; 2nd. sum and C to half adder table; 3rd. two carry to OR, the last sum is the sum.)
half adder table
A + B -> carry bit & sum bit (XOR and AND)
logic unit
Resistor and RAM
RAM(random access memory): AND-OR latch(the reset wire is used to set if the gated should be opened, which doesn't show in this picture)
for 256 store bit, we only need 35 wire with matrix to control it: 1 write wire, 1 set wire, 1 read wire, 16 wire for conlunms and rows.
A 256-bit memory can store 1 byte
The center process unit(CPU
decode phase——find the resistor through operation(first four bit for operation, last four bit for address)
execute phase——execute operation
fetch phase——fetch the operation from memory
instruction and program
The steps of program are stored, and their orders are matter.
Advanced CPU
instruction pipeline
You can use different part of CPU at the same time, but there are some dangers, for example, when we had to stop it and get a value, maybe it is a old value. We can use Out-of-Order Excution to solve it.
Conditional jump instruction
Trouble: it may take a long time to determine which road should it go, but we can write some program to guess the road. Now the probility of correct is more than 90%.
cache
cache can store a quare of datas, which can decrease Cache Missing time(request for datas from RAM)
dirty bit: Before the cache erease the old clock to free up space, it will check dirty bit. If it's dirty, the old block data is written back to RAM before loading in the new block.
early programming
Crash Course Science Computer
11~20
No.11 The first programming language
