WEBVTT

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ah usb one of the wonderful conveniences of

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modern life you just plug it into

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any one of the similar looking ports and things just work

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well most of the time anyway but whatever happened to those

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old-school massive things we used to use to connect printers and

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hard drives well older standards like ieee 1284 and ide

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cables had so many pins and took up so

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much physical space because they communicated in parallel meaning that

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they could send and or receive multiple bits of information

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simultaneously by contrast new school interfaces like

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usb sas SATA and individual pci express

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lanes are serial which fun fact is actually what the s in each

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acronym stands for these ones can only send or receive one

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bit at a time but wait a minute

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why on earth would that be better i mean when they close all but one lane on the

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freeway that's a bad thing well

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popular parallel standards had a number of limitations that slowed down their

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real-world speed these ports depended on all of the data

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lines sending the correct data simultaneously

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so trying to push more and more data

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through a parallel port per second means that it's harder and harder for those

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lines to stay synchronized meaning that as you increased the data rate the port

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actually had to slow things down and wait for all of the signals to match up

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another phenomenon called crosstalk also

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complicated matters crosstalk is basically electrical interference

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between data lines that are close together and it becomes more pronounced

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when you add more lines than again when

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you try to make them faster because a serial connection like usb

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only has one data line in each direction

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crosstalk isn't nearly as much of an issue

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this means that although serial connections can only fire off one bit at

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a time the rate of fire can be made much

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higher especially as electronics manufacturing in general has improved so

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think of an automatic machine gun shooting tons of bullets per second one

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at a time versus a break barrel shotgun

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that can fire lots of pellets at once but has a much longer reload delay

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parallel connections also had the disadvantage of using lots of pins to

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support transmitting multiple bits at once and that meant that the connectors

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themselves were more prone to damage

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think about how easy it was to bend printer pins or an ide header on an old

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motherboard modern serial links typically don't use

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protruding pins making standards like usb and SATA suitable for

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many more insertions as they say

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but Linus hold on a minute what about my fancy new graphics card that uses 16 pci

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express lanes at once isn't that parallel

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well not really each pci express lane has its

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own clock signal so they're not synchronized with each other the data is

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simply transmitted down each lane in a

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more independent fashion leaving the card itself to sort out the information

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which doesn't take very long meaning that pci express speeds scale very well

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as you add more lanes which you can see in high-speed pci express devices like

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solid-state drives and video cards pretty incredible right

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well that may be but as far as one bit

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at a time cereal technology has come i wouldn't bother trying to eat your bowl

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of frosted flakes one at a time do you really want your isp keeping an

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eye on what it is that you're doing online use tunnelbear tunnelbear vpn is the

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tunnelbear.com Linus so thanks for watching guys like

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dislike leave a comment with future video suggestions don't forget to

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subscribe and check out our other channels and i guess that's pretty much it i will see you again at the next fast

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as possible as soon as possible

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it's going to be as great as possible