"USB: Don't Speak unless Spoken to" T-Shirt on Teespring - Page 1
Forum section: electronics / general

author: MLM
author_rank: Contributor
timestamp: March 28, 2014, 07:41:49 pm
content: Just started a Teespring campaign for my "USB: Don't Speak unless Spoken to" shirt design.Visit the campaign:teespring.com/usbshirtExplanation:Each USB device on the bus has an unique address 0-127(7 bits). Every transaction includes a token packet which carries the address bits. Only the device configured for that address should listen or respond to the transaction. This maintains a collision free bus.Quote

author: Zbig
author_rank: Frequent Contributor
timestamp: March 28, 2014, 10:30:05 pm
content: I hate to rain on your parade but you know what they say about puns which need explanation...?

author: mazurov
author_rank: Frequent Contributor
timestamp: March 29, 2014, 12:43:43 am
content: You forgot remote wakeup.

author: MLM
author_rank: Contributor
timestamp: March 29, 2014, 01:00:22 am
content: Quote from: Zbig on March 28, 2014, 10:30:05 pmThis tweet by Travis Goodspeedsums up the message pretty well.The concept is similar to theEEVBlog negative feedback shirt. The explanation and source quotes are to reinforce the message.“Don’t speak unless spoken to” is an antiquated phrase usually told to children. Similar to “respect my authoritah”.Quote from: mazurov on March 29, 2014, 12:43:43 amI understand this has changed for USB 3.0 with pipes going in both directions, ERDY and NRDY notifications. But I think everyone is still pretty much in a USB 2.0 mindset except for mass storage.

author: linux-works
author_rank: Super Contributor
timestamp: March 29, 2014, 01:30:57 am
content: 802.4 and 802.5 (token bus and token ring) were like that, too. no love for the old school networking protocols?

author: Zbig
author_rank: Frequent Contributor
timestamp: March 29, 2014, 12:03:19 pm
content: Quote from: MLM on March 29, 2014, 01:00:22 amYes, I know Dave's design and it's obvious that's where you'd got your inspiration. Only I find Dave's one funny and yours - less so... sorryQuote from: MLM on March 29, 2014, 01:00:22 amYes, I got that, no need to explain this even furtherIt's just that I find the pun too vague and it doesn't really work for me. Negative feedback circuit is a basic and most common usage of an op-amp. And the play on words works really well there. On the other hand, USB being a polled interface is just one unobvious implementation detail. It's not something that immediately comes to your mind when thinking "USB".Or, let's try it another way:Ethernet: If at first you don't succeed...Explanation:CSMS/CD: If two guests start speaking at the same time, both stop and wait for short, random periods of time (in Ethernet, this time is measured in microseconds). The hope is that by each choosing a random period of time, both guests will not choose the same time to try to speak again, thus avoiding another collision (Wikipedia).Funny, yes? Nope, not really...

author: linux-works
author_rank: Super Contributor
timestamp: March 29, 2014, 04:23:27 pm
content: Quote from: Zbig on March 29, 2014, 12:03:19 pmthe interesting thing about the ethernet 'collision and backoff' idea is that by adding randomness, you get to decrease the amount of chaos! I always found that to be kind of neat.

author: Zbig
author_rank: Frequent Contributor
timestamp: March 29, 2014, 05:39:21 pm
content: Quote from: linux-works on March 29, 2014, 04:23:27 pmRight, that actually is quite smart. Ironically, it was purportedly frowned upon by the Token Ring proponents for this very reason. They somehow saw this randomness as inelegant and a not properly engineered design. Another thing is, we hardly see this mechanism in action anymore, in the days of all-switched Ethernet.

author: linux-works
author_rank: Super Contributor
timestamp: March 29, 2014, 05:51:12 pm
content: I got my first start in networking with token-BUS. a company that was big into it (concord data systems) was one of my first internships. they gave away trade-show gifts made of metal that said:"you can't get on the bus without a token"still makes me smile to this daytoken-ring was pretty stupid and evil but token bus actually did make sense. of course, ethernet fully took over but it was not so clear back in the 80's who would win this networking MAC war.

author: CanadianAvenger
author_rank: Regular Contributor
timestamp: March 29, 2014, 08:32:18 pm
content: Token passing schemes have the advantage of being deterministic, and are still used today where applications demand deterministic performance. Although token ring itself has mostly fallen by the wayside.As for the USB shirt, I thought it was cute, and got the reference right away, but felt it was perhaps a bit too obscure.

author: MLM
author_rank: Contributor
timestamp: March 30, 2014, 12:57:02 am
content: Quote from: CanadianAvenger on March 29, 2014, 08:32:18 pmThanks CanadianAvenger! I wholeheartedly admit it may be targeted at someone who has read the USB spec before, but that makes it all the more special to someone who gets it right away.

author: AlfBaz
author_rank: Super Contributor
timestamp: March 30, 2014, 01:05:41 am
content: Quote from: CanadianAvenger on March 29, 2014, 08:32:18 pmFairly certain Allan Bradly PLC's "Data Highway +" still use it

author: JTR
author_rank: Regular Contributor
timestamp: April 01, 2014, 09:25:57 pm
content: Quote from: Zbig on March 28, 2014, 10:30:05 pmAnd the explanation is itself incorrect.

author: Orpheus
author_rank: Regular Contributor
timestamp: April 05, 2014, 04:30:09 am
content: Well, I pledged. Happily. Best of luck!And if Dave's T-shirt ever comes back in black, I'll pledge for many. against the inevitable wearout (though I only wear T-shirts 1-2 days a week, I don't ever want to be caught without it. It only plays better each year as I begin my advance into geezerdom)

author: MLM
author_rank: Contributor
timestamp: April 05, 2014, 05:03:01 am
content: Quote from: Orpheus on April 05, 2014, 04:30:09 amThanks for the support Orpheus!I hope we can get it fully funded in the next couple days.

author: Neganur
author_rank: Unknown
timestamp: April 05, 2014, 10:34:56 am
content: I like my USB 3.0 devices white and ERDY...

author: MLM
author_rank: Contributor
timestamp: April 06, 2014, 03:21:24 am
content: Less than 24 hours remain.If there are 5 more sales, I can request to reduce the goal to 10 shirts. I think this is the best route to make it successful.Quote from: Neganur on April 05, 2014, 10:34:56 amWhy not white and NRDY?

author: edavid
author_rank: Super Contributor
timestamp: April 06, 2014, 02:48:19 pm
content: You might as well have a shirt that reads "Vaguely Hostile Nerd".