Mastodawn

Jernej Simončič �7h ago

@raymierussell Mine's a pull-behind variant, seems to have better suction than the previous one with bags had.

Jernej Simončič �7h ago

@cstross @johnefrancis We've had 23° in the morning, and it was so nice and cool :)

Jernej Simončič �7h ago

@raymierussell @vkc I've got both a Roomba S9+ and a bagless vacuum. Roomba runs daily while I'm at work, and I use the bagless vacuum for stairwell and two rooms that Roomba can't reach due to the step.

Every now and then Roomba does get caught on the frills one of the carpets has, but it's rare enough to not matter, and it cleans well enough for me (when my grandmother passed away, I put one of her carpets in my livingroom, and I thought I'd have to order a carpet cleaning service, since it was quite dusty and grey; but every day after Roomba made a pass, it was becoming visibly ligher, and after about 10 days it looked completely different, with very lively colours).

Jernej Simončič �8h ago

kajer 8h ago

Hello fellow hackers!!!

I want to give away the Flock Safety camera and battery pack I tore down a few weeks ago. The Serial header has been soldered to and the back 7 pin connection has been cut to trace voltages and I2C busses.

Otherwise the android OS is factory-ish minus the install of magisk root to access the filesystem. I did not overwrite the boot loader, but can give you the root enabled boot loader to call from fastboot.

I want to pass on the camera to someone who can continue to dissect the OS and the APPS publicly. I don't want the camera to go to a CVE hunter.

Thoughts?

Ada Worcester 🏳️‍⚧️9h ago

@munin unfortunately, i fear that they will only be removed from their positions after they succeed at bringing disaster

Sarah Taber 10h ago

So. I've been on field manual labor crews where most of my coworkers were convicts.

I've also worked with a lot of tech companies on automating farms.

And this press conference is incredible. Rollins hasn't the foggiest clue what she's on about.

https://petition.parliament.uk/petitions/704793

Shouty person 3d ago

If you’re a UK resident and/or a UK citizen, please make sure you sign this petition. It’s at almost 80k signatures and it’s got 3 weeks left to get to 100k.

‘Legally enshrine the right of adults to physically transition using NHS services’

#trans #TransRightAreHumanRights

Petition: Legally enshrine the right of adults to physically transition using NHS services

Introduce a law to legally protect the right of those aged 18 and over to transition using NHS services. This should specifically cover physical transition, including hormone treatment and surgery, as otherwise I believe it could potentially be interpreted as including conversion therapy.

Petitions - UK Government and Parliament

Eugen Rochko 1d ago

There is a new setting for server operators in #Mastodon 4.4, under Administration -> Server Settings -> Discovery, called "Allow external sites to see your Mastodon server as a traffic source". If you're running a server for a larger group of people there is no privacy downside to enabling this, and it will help make the fediverse more visible as a traffic source to the rest of the web.

Yes, a file full of zero bits transfers faster over USB2.0 than a file full of one bits.

I've known this forever but it still feels ridiculous when you actually test it and it's true!

USB truly is cursed.

Adrian Tombu 1d ago

@lina But... why? 😳

@to Because USB 2.0 has to throw in an extra dummy zero bit every 6 consecutive one bits or else it loses its place in the data!

5225225 1d ago

@lina @to i'm surprised that doesn't also apply to long spans of zeros (so 0b01010101 would transfer the fastest of them all)

@5225225 @to It's NRZI encoded so a long span of zeros is actually sent as 0101010101!

Cloudmom Colette 1d ago

@lina @5225225 @to I'm so glad I'm moving from USB to ethernet on my side project for data transmission

Give me UDP before USB ever again

Cloudmom Colette 1d ago

@lina @5225225 @to luje: I was DISMAYED to not be able to beat 2Mbit of goodput on that project. Part of it was the STM libraries not having a good USB implementation for their own baked in transciever but mostly its just a nightmare to try to squeeze performance out of. Since I was facing interacting with an external PHY either way— ethernet seemed far less intimidating and problematic

Wilfried Klaebe 1d ago

@lina The USB 3 high-speed pairs use something better, nor?

@5225225 @to

Marcus Müller 1d ago

@wonka @lina @5225225 @to I mean, yeah, USB 3 uses 8b/10b in USB3 (or 128b/132b in errr USB 3.2 Gen 2×1 and 2×2, but not in 1×2) as line code.

Samantaz Fox 1d ago

@lina @to Oh, so kinda like bit stuffing in CANbus where an extra bit of the opposite level is added after 5 consecutive bits of the same value.

However I don't understand why in USB it only applies to ones and not zeroes.

EDIT: Just reat the other post about NRZI coding, it now makes perfect sense! But that remains cursed nonetheless x)

Maypop the Dragon 1d ago

@lina @to why six

Maypop the Dragon 23h ago

@lina @to hey undyne what is one more than the number of consecutive 1 bits that can be sent over usb 2.0 before sending a dummy 0 bit

#undertale #shitpost

doragasu 1d ago

@to @lina Google "bit stuffing". That's the reason.

PortabelloBelle 🇪🇺 🏳️‍⚧️1d ago

@to @lina

1s are heavier 😁

PortabelloBelle 🇪🇺 🏳️‍⚧️1d ago

@to @lina

Speaking of weight, does physical memory get heavier the more data you add to it?

@ArabellaLovejoy @to Take this with a grain of salt, but I get that a modern SSD using 3D NAND gains around 0.05 picograms per terabyte of data stored. 0s are heavier and an empty SSD is all 1s.

Roughly going by the cell geometry and electron density mentioned in this paper, which works out to around 300 electrons per programmed cell, taking 150 as an average (whitening) and assuming TLC flash: https://www.jstage.jst.go.jp/article/elex/17/23/17_17.20200335/_pdf

This does not apply to RAM since that uses capacitors, so you take electrons from one side and move them to the other, so no net weight change.

Räucherkäse 1d ago

@lina @ArabellaLovejoy @to Nitpick: DRAM is capacitors, but SRAM isn't. On the other hand, latches are usually symmetric, so they may balance out nicely, too.

@smochi @ArabellaLovejoy @to SRAM is also (gate) capacitors, just statically connected to the voltage rails via a feedback path instead of dynamically refreshed ^^

PortabelloBelle 🇪🇺 🏳️‍⚧️1d ago

@lina @smochi @to

When I posed this question, I was expecting to get a chuckle, or perhaps a bit of philosophy, I'm astonished that I got this wonderful information in response to what I thought was a bit of whimsy.

Cassandrich 23h ago

@ArabellaLovejoy @lina @smochi @to There's probably also some cursed phenomenon by which the entropy difference imposes a mass difference.. 🙃

https://bigthink.com/hard-science/dark-matter-theory/

C++ Wage Slave 10h ago

@dalias

I'm not sure whether you were joking, but, yes, there is a plausible theory that information has mass:

@ArabellaLovejoy @lina @smochi @to

There is no dark matter. Instead, information has mass, physicist says

Is information the fifth form of matter?

Big Think

Räucherkäse 1d ago

@lina @ArabellaLovejoy @to Strictly speaking, the gate capacitors do play a role, but they are not exactly designed to be the information carriers. If you build an SRAM cell with BJTs, it's the small hold currents and the transistor's switching thresholds that store the information. The same is true with FETs - the hold currents will just keep the gate capacitors in charged/discharged state continuously. But you're not wrong - you can totally look at this from different angles.

Eragon 1d ago

@lina This is so cursed.
Is it still true in USB 3.0 (or 3.1 or any other newer revisions with their cursed naming scheme)

@eragon It's true with all 480Mbps and slower devices. For USB 3.0 SuperSpeed instead they just did a misleading marketing and the "5 Gbps" they advertise are instead 4 Gbps, but at least it's independent of what data you send. See my previous thread for some discussion on that...

Ember

1d ago

@lina does it interpolate between the speeds? like, would sending a 90% zeros file be faster than a pure random file?

@Ember It depends on the distribution of the bits. A file that is 90% zeros all in a row and 10% ones all in a row (1.6% overhead) would actually be slower than a pure random file that is 50/50 (0.8% overhead).

Gerard Braad 1d ago

Everybody knows zero weighs nothing... ;-)

letterbeen 1d ago

@lina
So, theoretically, you could make a faster transfer mechanism that counted the amount of 0s, and conditionally flipped every bit before and after the transfer? You would have to read the whole file twice though, so probably not a practical solution 😅

Wilfried Klaebe 1d ago

@letterbeen or "just" use a compressing content transfer encoding like gzip 😉

@lina

Cassandrich 23h ago

@letterbeen @lina Easier than that, just encrypt it.

mmu_man 1d ago

@lina I suppose the encoding used forces a maximum number of contiguous ones by inserting symbols or something… or there's a special empty block frame like sparse files on disks?

@mmu_man It inserts a zero every six consecutive ones.

Z̈oé ⛵1d ago

@lina Few people know it but the reason for this is very simple. While zeroes are round, a 1 has a sharp corner and a hook that could get stuck and damage the insulation around the copper if you would completely fill the line with ones. Instead, sending some zeroes every now and then to flush any stuck „1“ before a clog can develop.

A 0 can be neatly pushed through the copper at high pressure without damaging the cable.

Now you know!

KaustcVantas 1d ago

How did we ever survive in the age without /s tags

#With-gusto-and-panache #apparently

rastilin 23h ago

@kaustcvantas @lina @uint8_t@chaos.social

I think people tend to forget that ironic shitposting is still shitposting.

Stefan Eissing 1d ago

@uint8_t @lina Should have imagined more complex bits. Then we'd have 0 and i.

Z̈oé ⛵1d ago

@icing @lina the problem with i is that it’s often used in for loops so it could get entangled in the software threads, or its value might change unexpectedly and rapidly if it gets into the wrong scope

Efraim Flashner 1d ago

@uint8_t
Sometimes you have to stop what you're doing and find the dots which have fallen off the top of the is. It's been proven that despite the 1s getting suck on corners it's still faster than searching for the dots.
@icing @lina

lp0 on fire

1d ago

@efraim @uint8_t @icing @lina, ı·iıi·.ı0i·iı

C++ Wage Slave 10h ago

@uint8_t

In addition, if the USB cable is kinked, the dot of the i can snap off the body. Now you have two bits where there was one before, causing a buffer overflow.

@icing @lina

@icing @uint8_t @lina thats done with QPSK but not on usb links.

Räucherkäse 20h ago

@icing @uint8_t @lina It would make interface circuitry much more complicated, because you'd have to consider every signal from an imaginary angle.

Stefan Eissing 20h ago

@smochi @uint8_t @lina This seems to happen on the internet a lot already.😌

2¢1d ago

@uint8_t @lina Finally, someone explains NRZI so it makes sense!

@Qbitzerre @uint8_t @lina Usual line coding is NRZ, which encodes bits in levels. 1 high 0 low, simple.

But USB is NRZI-S, it encodes bits in level *changes* : https://en.wikipedia.org/wiki/Non-return-to-zero#Non-return-to-zero_inverted

This means a zero is encoded by a level change and a one is encoded by no change. You need bit suffing because USB does not transmit the associated clock, and with no transition in long strings of ones, the receiver would loose sync.

Non-return-to-zero - Wikipedia

2¢16h ago

@f4grx @uint8_t @lina ah, clocks! makes me nostalgic for the days of bisync, SDLC, etc. The serifs on the ones were very big in those days. We used axle grease to keep the current loop devices from getting constipated.

Mark T. Tomczak 1d ago

@uint8_t I am so angry about how close to the actual explanation this is. 😉

Ryan Peters 8h ago

@uint8_t @lina my pipes get the same way.

I use drain-0

Mensch, Marina 1d ago

@lina but data is Data, or Not?

Jean-Baptiste Quéru 1d ago

@lina That was similarly true on the ZX Spectrum, a 0 took 0.5ms whereas a 1 took 1ms.

Aatch 1d ago

@lina eh, "cursed" seems a little harsh. The NRZI encoding and bit-stuffing makes sense for real-world scenarios.

Marc 1d ago

@lina gah thanks Lina now "bit stuffing" is in my work Google history

Janek @ IndieDev.site 1d ago

@lina the USBus is coming

#memes #programmer_humor #funny

Jan 1d ago

@lina It’s interesting to see how the standards evolved.
Since USB 3.0 it uses an 8b/10b scheme, 3.1 Gen 2 moved to 128/132b.
Do you know what kind of hardware improvements made this possible? Better clock stability of the transmitters?

Keenan Tims 1d ago

@jangw @lina I'd assume just a desire to keep implementation complexity low to satisfy the Universalness of USB, and since its overhead on random data is less it should have slightly better real world throughput. 8b/10b was in use in the 80s so it was certainly a known option, but implementation is quite a bit more complex than bit stuffing. It was probably more that DC balance and lowering the required channel bandwidth became more critical at higher speeds.

Carlos Solís 1d ago

I wonder if that has to do with the zeroes requiring less voltage to transmit than the ones.

Greg Brooks 1d ago

@lina but what if the 1s were standing up instead of lying down end to end?

John Ripley 1d ago

@lina Bit stuffing also makes all transfers slower, due to the difficulty of predicting the transmit time (size) of a packet vs the timing of frame end. Generally results in one less packet per frame.

MacBalance 1d ago

@lina A theory: I vaguely remember reading about signal formatting for telecom (probably elderly T1 signaling or similar) where a specific pattern of bits was used for control signals. If the data had this pattern, there was a workaround to allow it.

Perhaps the USB standard has some similar aspect, so the transfer has more overhead as the host has to constantly say “you’re not going to believe this, but there’s some more empty bytes coming.”

unixjunk1e 🌵23h ago

@lina The computer will still have to read the bits