Ask Ubuntu General Room

Avery

00:14

> ZRAM creates a virtual compressed Swap-file in memory as alternative to a swapfile on disc.

what

compressed swapfile in ram?

Why

why not just compress stuff on ram, why deal with complexities of swapfile

TheWanderer

yes

Avery

but why

Nathan Osman

Isn't that easier?

How would you compress RAM?

You'd have to intercept memory reads / writes at the application level.

It's much easier to have the kernel handle memory - and the easiest way to do this is with swap.

TheWanderer

01:05

yes

TheWanderer

01:46

hmm my cat isn't cleaning himself....

and he has an infection on his neck

this can't be good

Android Dev

02:21

@TheWanderer so you might be interested to know that I'm in the process of repairing someone's iPhone 5s... It was thrown across a parking lot, and the display was completely shattered, with chunks of glass falling out from the front and back, to the point where you could see the front camera and earpiece assembly. I turned it on with a replacement display connected but not screwed in, and surprisingly the motherboard is still alive

Looks like the cellular radio or at least the antenna is shot though

Nathan Osman

02:47

Oh my.

Artful Aardvark

03:07

@NathanOsman heh, i switched to chromium and it let me in

@NathanOsman whats up

Nathan Osman

Not much.

Except I did make the front page of Hacker News.

Artful Aardvark

@NathanOsman can you link me?

Nathan Osman

blog.quickmediasolutions.com/2017/09/28/…

Artful Aardvark

by the way

@NathanOsman 2buntu.com/articles/1489/installing-ubuntu-touch-on-a-nexus-5 how do you do that on 16.04?

asking you because you wrote the article

Nathan Osman

My Nexus 5 is currently broken :(

Artful Aardvark

03:12

@NathanOsman yeah i got one for plasma mobile but it SUCKS

its slow as hell

keeps crashing

accomplishment enough to get it going though, as the flash tool loves to cause errors

1sec switching comps

Rinzwind

04:17

lol I got a 12.04 badge :=D

Kaz Wolfe

05:05

please kill me

i'm looking through some really old code of mine.

and we apparently invented our own messaging bus. for some reason.

Journeyman Geek

pkill -9 @KazWolfe

Kaz Wolfe

05:23

thanks

Nathan Osman

05:50

Halp. I'm writing a parser for JPEG files.

:P

Kaz Wolfe

Halp.

I'm trying to reverse engineer the messaging bus my team wrote.

5

And port it into something sane.

I even have the source code. It's still hell.

Nathan Osman

Messaging bus?

Oh no.

It's too late.

Journeyman Geek

@KazWolfe Eventually, the sun with explode. Taking out all life. Then, maybe then, in the last dying cinders of our world.... actually no, damned thing will find its way into space. We're all damned men, DAMNED. ;p

Kaz Wolfe

it gets worse @NathanOsman

the entire messaging bus is really just an api that different servers call

so we built our own http applet from the ground up to send messages between servers.

(which we affectionately referred to as Packets in the source code.)

Nathan Osman

No! Stop!

I ̍͆̐͑c̔ȧn͗not̑ h͍̫͉̖͡elp̋ ̝̩͉̤͎͒̅͋̒you ṋ̥͍͚̝̎o̿w̭̱̯̼̭͊.

Kaz Wolfe

05:56

The serialization itself gives me a massive headache.

Nathan Osman

Why not just use HTTP?

Using Unix sockets or something?

Kaz Wolfe

well, here's where it gets better

do you want to know how we handled load balancing?

Nathan Osman

Uhm... do I?

Kaz Wolfe

(e.g. where it didn't matter what server a message went to)

do you?

Nathan Osman

I don't know if I dare.

Kaz Wolfe

06:00

ok well

we were planning to use anycast.

Nathan Osman

I almost fell off my chair just now looking at some code I wrote a year ago.

@KazWolfe The horror!

That sounds really really complicated.

Kaz Wolfe

So... this is a homemade (strike 1) message bus, completely written over HTTP (strike two), where messages were often sent in anycast (strike 3).

Nathan Osman

I've barely got my head wrapped around IP multicast.

Kaz Wolfe

it gets better

Nathan Osman

@KazWolfe You should just switch the entire thing to Redis.

Kaz Wolfe

06:01

do you want to know why we did this monstrosity?

Nathan Osman

Sure.

Why not.

Kaz Wolfe

because we didn't want the app servers to write to the databases.

only the "trusted" backbone servers - which were the load balancers by the way - were allowed to talk to certain parts of the DB.

Nathan Osman

Can't you manage that with privileges and user accounts?

Kaz Wolfe

we did.

Nathan Osman

Oh my.

Kaz Wolfe

06:02

we enforced that with Mongo's privileges. We still needed to get messages to the backbone somehow.

Nathan Osman

Wait - so the servers can't write to the database so they ask the load balancers to write?

Kaz Wolfe

yep.

well, sorta

Nathan Osman

Drops to his knees.

Kaz Wolfe

the servers can't write certain records, like changes in permission

Nathan Osman

Runs for the nearest exit.

Kaz Wolfe

06:04

it still gets better

our primary data store is MongoDB (obviously)

Nathan Osman

That itself is enough to make me run.

Kaz Wolfe

The backbones are all interconnected through Redis because memory stupidity.

eh, mongo's okay for our use case

we don't need immediate consistency or anything so it's not too bad.

Nathan Osman

Well, that was entertaining.

Sort of.

In a disturbing sort of way.

Kaz Wolfe

oh i'm not done

guess where our DAOs were?

actually you won't be able to

Nathan Osman

The lunchroom?

Kaz Wolfe

06:08

Our DAOs for our objects were in the objects themselves as statics.

We literally had this as a line of code in our project:

User user = User.getUser(uuid);

Guess where the caching was.

If you said "In the object class as a static HashMap", you'd be right.

i hate this code. so much.

and i need to sleep

Nathan Osman

06:32

Goodnight.

I need sleep too.

So that I can wake up tomorrow and write my JPEG parser.

:P

Ubuntu Questions on U&L

06:47

0

Q: Linux Ubuntu, NFS for logs and cache, NFS or GFS

my company has no dev ops person and I am developer so I hardly know the best practices of dev ops as I am new to it, so please forgive me for any mistake. I have two Ubuntu machines. Each of them have a exact SAME web server and hence they give access logs. They both are running ruby on rails w...

Benny

07:45

Morning

I think should be close

-4

Q: Are the Linux install and Boot loader install separate locations? [ORIGINAL ISSUE FIXED]

-ORIGINAL ISSUE FIXED BY WAY OF COMMON F**KING SENSE- Okay, so i know i need to use SDC3 to install Linux. But now i have another question. When you select something in the larger list, the Boot Loader installation doesn't change, and when i select a different Boot loader install area, the main ...

dual-boot partitioning hard-drive

Ubuntu Questions on U&L

13:38

0

Q: disk free command: unundesrtood output

On one of my machines, I accidently typed *.* following the disk free command: df -h *.* I got this output: Filesystem Size Used Avail Use% Mounted on /dev/sda1 455G 26G 406G 7% / /dev/sda1 455G 26G 406G 7% / /dev/sda1 455G 26G 406G 7% / /dev/sda1 ...

ubuntu disk-usage output

yode

14:52

My ubuntu 14.04 have so many python version..

Could I uninstall that v3.4 but not affect the v3.6?

Anybody can tell me some thing?

Of course I know apt remove python3.4 can do this ,but I afraid it will uninstall those dependence python3.6 also

Journeyman Geek

you could simulate the removal and see

-S wasn't it?

yode

"simulate the removal"?

First time to know it..

@JourneymanGeek Hi, I cannot find any informaton about -S in man apt

Ok,I have find it now in man apt-get

Journeyman Geek

15:17

I'd test it with something less dangerous first of course ;p

yode

15:58

What is that 3.4m and 3.6m?

TheWanderer

17:37

wtf

amazon.com/MSI-GS63VR-Stealth-i7-7700HQ-Keyboard/dp/B072K85Z7N

how the hell did they manage that?

GTX 1070 in 0.69" and 3.96lbs

Rinzwind

heck windows 10 alone weighs a ton on its own >:-D

TheWanderer

kek

Nathan Osman

Lol.

TheWanderer

19:53

rip AUGR

livin' the dongle lief

mDP-->HDMI, USB-C hub

whee

affinity.serif.com

what do you guys think about that software? ^

TheWanderer

22:15

ebay.com/itm/…

why?

why would someone pay more for a downclocked Note 7 than the Note 8?

mmmm pierogies

TheWanderer

22:48

I'm so confused

I released an update to SystemUI Tuner and it got 6 reviews in like 3 hours

Nathan Osman

That's... good?

TheWanderer

ah, two were updated reviews

but still, that's a lot

and idk where they came from

unless the app was shared on Reddit again

Nathan Osman

I like the new icon, BTW.

TheWanderer

what is it now?

I can't remember

Nathan Osman

Some bug thing.

TheWanderer

22:55

ah yes

Huawei has nice hold music

Nathan Osman

A rounded rectangle with 3 horizontal lines and two antennae.

TheWanderer

but like 2 representatives

@NathanOsman is it antennae or antennas? Because it's a bug, but it's an electronic bug

:D

Nathan Osman

Ah.

Ubuntu Questions on U&L

23:49

0

Q: Stopping the IP connection between a client and the server for 30 seconds and rewarm up of the link after that period

Here is my configuration: On the server I have a DHCP server that gives IP addresses to clients (connected on eth1) in order for the clients to be connected to the internet (on eth0). For a special operational use, I would like to stop the IP connection between a client and the server for 30 se...

ubuntu networking iptables windows dhcp

Android Dev

@NathanOsman so I found a bug in the Android OpenCV API

that causes libc to crash with a Fatal signal 8

Nathan Osman

Oh?

Android Dev

turns out it was a null pointer error

but their API should have caught that

Nathan Osman

But all it will do is crash your app.

Android Dev

yeah, but no stacktrace because it was an error in the native code

I found a stackoverflow question from 2012 with the same error

It isn't answered

I wonder if they had the same issue

0

Q: OpenCV on Android Core.inRange Error and APP crash

I use OpenCV on Android. But the function: Core.inRange(img, new Scalar(127, 127, 127), new Scalar(127, 127, 127), img); crashes on the second call with "Fatal signal 8 (SIGFPE) at 0x00002a01 (code=0)"?

android opencv

so idk if I should answer it

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Ask Ubuntu General Room