SIO bus - USB bus question

[+Philsan]

I have read, for example in Atari Historical Society website, that SIO bus is a simplistic version of the USB. In fact the USB and the Atari SIO have a lot more in common then many would think. One of Atari's original computer engineers, Joe Decuir who created the Atari SIO bus is also one of the team of engineers at Microsoft to help design and holds patents on the USB.

Can someone explain to me why this bus is so particular, compared with other home computers buses of the time?

[Rybags]

Just about any legacy serial protocol could claim things in common with USB.

 

We had a debacle about "Atari invented USB" not long ago.

 

Really, the Atari SIO wasn't exactly unique - Commodore's is similar in that it daisy-chains and has unique device IDs on the bus. The only reason it doesn't get many accolades is that in it's default form it was so painfully slow.

 

Anyway, SIO uses old fashioned 10 bits per byte transmission, where I believe USB uses the more advanced 8 to 14 bit encoding which allows mega speeds as the encoding guarantees that bit value transitions always occur within set time periods which allows resync between devices to occur much more frequently.

[danwinslow]

I think it was the idea of addressability that was the main feature of SIO that they are referring to, that is, a header on the information that routes it to a particular device of several devices that were chained in. USB shares that idea very basically, and is technically a serial interface, but the level of software complexity behind USB makes it really meaningless to compare it to SIO.