dis-sys

look at that photo on the top, simply a piece of art. just incredible.

yes, 1m for every 3.3ns error, we all know that.

the problem is those GPS vendors only provide long term average error for their products, there is upper bound guarantee at all.

My preyer are with those brave rats who died for the peace of mankind.

wondering is there any upper bound on the error, e.g. is it possible to ever have a timing error of say 100 microsecond seconds.

A quick question related to this blog -

they mentioned that most modern NICs have hardware timestamp capabilities, that is consistent with what I saw. The question is what is the availability of those PTP ready & enabled routers/switches capable of acting as a Transparent Clock? I have two concerns, most of existing routers/switches are not PTP ready, even for those ones with PTP capabilities, its PTP related features may not be enabled in production. Any experience or numbers to share? thanks!

Nice tech blog, really love it.

From my understanding, basically this new iteration is better then their previous generation chrony based one because the uncertainty in the One Way Delay calculation is largely removed by having those Transparent Clocks capable of reporting their queuing delays. Basically the asymmetry of the delays are gone?

Personally, I don't think Chrony should be considered as a NTP implementation as clearly it can utilize those PTP hardware timestamps as well and those hardware timestamps are the "secret sauce" of PTP's high accuracy. With those PTP enabled switches, together with the fact that Chrony can already send NTP packages as PTP packages, surely Chrony can leverage such new capabilities as well with some reasonable updates.

Wait until you hear about the leap years! They insert a whole day, often right in the middle of the work week!

That is pretty fine tuned given they only insert a full day. ;)

In Chinese lunar calendar, and probably other calendars as well, they insert a full month known as the leap month. Yes, you hear me right, 13 months in such leap years.

Too bad there weren't any computers around at the time or software developers might have convinced Julius Caesar what a disaster and source of bugs that will be for centuries to come. He might have dropped the whole idea.

Indeed. Such 2000 years old garbage is just not very compatible with modern way of life in which lots of things are being changed. From memory, in a few years, the definition of a second will also be reviewed by the international community. The current definition based on some funny behavior of Caesium atom is no longer the best. UTC is another drama deserve to have more care.

In 2022, there are not many international matters that can be agreed upon by US, EU and China at the same time. Getting rid of this stupid leap second disaster is one of those rare ones. US, EU and China all agreed that leap second should be eliminated. It is a disaster.

The whole leap second disaster is just beyond imagination - inserting a full second into the system during business hours in Asia when some of the world's largest exchanges are in trading session! When there are hundreds of millions time sensitive devices manufactured by tens of thousands different vendors at vastly different skill levels!

When compared with this leap second invention, Y2K problem is so harmless.

http://bitsavers.informatik.uni-stuttgart.de/pdf/borland/tur...

Turbo C 2.0 user manual from the same site - it is just a gold mine.

glad you mentioned meituan, it is prefect example on how low you can go to survive in business.

let's be honest, meituan is mostly used by not well educated & low income people who don't know anything about food safety & personal hygiene. Quite often you get "food" delivered from some dark alley home to tons of mouses & cockroaches. There are a crap load of videos uploaded by those meituan delivery guys showing people how awful are those "food" & places where "food" get prepared. e.g.

https://www.ixigua.com/6659332103689208333?logTag=a74d3ebf56...

In case of any doubt, just ask your friends will they be willing to feed their young kids with those "food" from meituan. ;)

Incredible, hope your sister's remission to be a complete & permanent one.

Literally curing cancer, just incredible.

great story, for me another interesting part is that lots of those tools/utils used in their dev work were copied from that dude's home, surely that is very reproducible & auditable.

I used to pay $800-1,000 a pair, then I heard that the exact same glasses from the exact same factory just without that fancy logo costs you about $100 a pair. Bought a few of them, never looked back.

People need to accept that you get ripped off all the time, it just a normal part of everyday life. when you think a $5 walmart tshirt is cheap, well, the factory gets probably 50c.

like millions of others

Including Xi Jinping.

Other than the annual university entrance exam and buying properties, Hukou is no longer enforced. The real difference only exists for tier-1 mega cities like Beijing and Shanghai, 97% Chinese don't live there.

I don't see any problem here as long as workers get freely to choose whether they want to live in factory dorms or in any other arrangements they can afford. Clearly such choice is available to them and there are numerous reports online that young workers are increasing choosing not to live in factory dorms. e.g. the following report talks about young female workers usually choose to move out of the factory dorm when they got boyfriends.

https://www.163.com/dy/article/DQQLE6DM0524PO2V.html

I don't think anyone here has the rights to tell those workers where to live.

do they use bash and vim as the default shell & editor?

Is there anyway to get it from the outside of the US?

covid zero is getting more and more like economy zero.

During a Chinese launch I see super strict hierarchy. People looking damn serious. How can you ever succeed without having motivated , out of the box thinking people.

first, some "out of the box thinking" - https://www.youtube.com/watch?v=hZyJdxzjGN4

this is a sad news.

adoption of ARM just started to pick up in server & laptop market, it could be a nice alternative to x86, yet short sighted decisions like this from ARM is going to cause huge uncertainties.

RISC-V is great, I am all for it, but let's be realistic, many people including myself have been waiting for 2 decades to see the current upward trend of ARM in servers & laptops, how many extra years we will have to wait for RISC-V to catch up and get to ARM's current position? An extra 5-10 years? Intel must be laughing!

As an ex-ARM & ex-Qualcomm employee - middle finger for both companies, you greedy licensing bitch.

this is not just source code, it is much better to be called magic.

also love the story behind it.

very interesting stuff. wondering is there any in-depth walkthrough of the time keeping mechanisms in Linux?

realizing that I would be long gone by 2603, your reply made me really sad. then I realized that your calculation is obviously wrong.

can I sue you for such such emotional distress?

1. NT kernel is neither novel nor used by anyone other than MS. Open sourcing the NT kernel would effectively kill the project as its security issues would be fully exploited with wide range impacts on literally everyone.

2. LLVM/Clang are not GPL licensed, they are apache 2.0 licensed. Open sourcing contribution is just open source contribution, it is not about whether you get to choose the license or not.

3. Well, SQL Server is a pretty good demonstration that proprietary database software can survive for decades.

To be fair, Apple actively participates in a long long list of open source projects, to give you some comparisons between Apple vs Microsoft -

* MS still refuses to open source its windows kernel to the public. Apple has its kernel accessible by the entire world.

* MS still refuses to open source its c++ compiler. Apple has swift built by the open source community and there are llvm/clang.

* MS still refuses to open source its sql server, when Apple has FoundationDB for the world and actively contributing to Apache Cassandra.

We are talking about a company that for many many years called open source a cancer.

All my workstations at home use ECC Reg RAM purchased online from ebay/alibaba. Most of them are from vendors selling "decommissioned" server parts. There are several good incentives to do that -

such second hand server parts are cheaper than normal consumer grade parts you get extra protection & performance

256GB (32GB x 8) Samsung DDR4-2933 ECC Reg RAM for USD $550, it is pretty hard to say no to that.

thanks for the info. this is exactly what I am doing. it does provide extra peace in mind knowing that my odds of having silent corruption is further reduced by doing such monitoring.

I don't think I'm ever going to use a non-ECC desktop again, the additional cost is not that high for the extra safety against silent corruption.

same here, but sadly you don't get to choose what you get when purchasing laptops, it is simply impossible to get ECC ram if you run mbp.

interesting, so they are actually using Ryzen with ECC RAM (when most people would be using Ryzen with non-ECC RAM) and that saved them from some seriously corrupted data written back to their persistent storage.

wondering is it common for people to specifically monitor their system log for correctable error related messages, do they consider the memory is faulty when there are correctable errors?