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by allfox
Mon Aug 06, 2018 6:53 pm
Forum: Networking and servers
Topic: Multicast Client
Replies: 4
Views: 195

Re: Multicast Client

Is there any encoding or compression with the audio stream?

If they are RAW data, you could just redirect them to aplay:

./your-program | aplay [parameter to define RAW format]

https://en.m.wikipedia.org/wiki/Aplay
by allfox
Mon Jul 09, 2018 9:51 am
Forum: Advanced users
Topic: Is there a performance penalty to using two byte structs instead of 4?
Replies: 16
Views: 624

Re: Is there a performance penalty to using two byte structs instead of 4?

I have some uncertain about this.

I think it's the compiler make the decision. If it is optimizing for speed, it could fit the 2 bytes struct into a 4 byte aligned space.

And I have an unsure illusion that Windows would fit anything into 8 byte aligned space.
by allfox
Mon Jul 09, 2018 9:40 am
Forum: General discussion
Topic: Setting a static IP address from SD card before boot
Replies: 19
Views: 732

Re: Setting a static IP address from SD card before boot

[*]Static IPs still require the router to be configured NOT to use those addresses. I agree with "Don't do that." for static IP. However, I'd like to mention that some routers would check if an dynamic IP is usable before assigning it to a client. The dnsmasq would send a ICMP ping to make sure the...
by allfox
Thu Jun 28, 2018 10:49 am
Forum: General discussion
Topic: Why didn't we go with Mali?
Replies: 139
Views: 19102

Re: Why didn't we go with Mali?

I recently see an Android tablet with Mali priced at 90 US dollars is able to decode HEVC(x265) by hardware. I wish that HEVC unicorn works on Pi either. My tablet, and the laptop I'm typing now is not able to accelerate HEVC either. They are old, bought in 2013 or so. Anything newer than 2016 shoul...
by allfox
Sat Jun 23, 2018 12:35 pm
Forum: General discussion
Topic: Network Monitoring
Replies: 4
Views: 265

Re: Network Monitoring

I think iptables could log traffic, like this: # iptables -nv --list .... 0 0 RETURN icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 0 0 0 RETURN icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 3 44 1856 RETURN icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8 0 0 RETURN icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 11 0 0 R...
by allfox
Tue Jun 12, 2018 11:45 am
Forum: General discussion
Topic: Automatically update project onto many headless pi
Replies: 8
Views: 237

Re: Automatically update project onto many headless pi

I remember there are platform program which let you update those IOT Pi on the air.

They overwrite the whole image when update.
They load the image into memory before execute it, so you could cut the power anytime.

But I can't recall the name!
by allfox
Tue May 08, 2018 8:30 pm
Forum: General discussion
Topic: Controlling LAN LEDs individually
Replies: 37
Views: 17189

Re: Controlling LAN LEDs individually

​There is an dtparam that can control led behaviour - see https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README#L96​ It was added March 21, so requires a kernel newer than that date. Would this work for Pi 3 v1.2 ? Because mine still keep blinking after I add dtparam=eth_led0=14 ...
by allfox
Mon May 07, 2018 5:51 am
Forum: Advanced users
Topic: About SSH brute force attacks.
Replies: 19
Views: 857

Re: About SSH brute force attacks.

I agree that key pair authentication won't send the private key out. But I doubt about "there is no key to guess". Think about these steps: 1 Server send a challenge of a public key encrypted random number. 2 I make up a private key, and use it to decrypt the challenge. 3 If the server don't let in,...
by allfox
Sun May 06, 2018 7:44 pm
Forum: 日本語
Topic: MySQLが導入できない
Replies: 2
Views: 845

Re: MySQLが導入できない

https://wiki.debian.org/MySql このページによると、Debian Stretch、つまりRaspbian Stretch、はsudo権限を持つユーザーがデータベースをアクセスできます。 piユーザーはsudo権限を持っています。 つまり、piでログインしてから: $ sudo -i # mysql USE mysql; CREATE USER 'YOUR_SYSTEM_USER'@'localhost' IDENTIFIED VIA unix_socket; exit; ここから、YOUR_SYSTEM_USERはsudo権限なしでもアクセスできるようになります。 ...
by allfox
Sun May 06, 2018 7:37 pm
Forum: Advanced users
Topic: About SSH brute force attacks.
Replies: 19
Views: 857

Re: About SSH brute force attacks.

There is something called "fail2ban", it would read the /var/log/auth.log, and block any IP that brute forcing your SSH daemon, for 10 minutes. You need to know some iptables to manually configure it. But if you never played with your iptables, then by default it would work. Install it with: sudo ap...
by allfox
Sun May 06, 2018 7:32 pm
Forum: Networking and servers
Topic: Raspberry Pi as Wifi Router
Replies: 1
Views: 240

Re: Raspberry Pi as Wifi Router

Here is an official document: https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md While this idea would work, a Pi access point would be less powerful than those commercial ones. I used an ath9k_htc based USB WiFi adapter to do this, it only allow 7 clients to connect at...
by allfox
Sun May 06, 2018 7:20 pm
Forum: General discussion
Topic: Power supply for raspberry pi 3
Replies: 11
Views: 499

Re: Power supply for raspberry pi 3

The Chinese on it says it's a phone charger. So, while it might be working, I suggest you get a real power supply unit. I don't know the output either. Maybe you need post another photo about the backside. The brand says XIAOMI, it's a little strange, as the 小米 I know would brand as MI, not XIAOMI: ...
by allfox
Mon Apr 30, 2018 9:31 pm
Forum: General discussion
Topic: NOOBS - Why?
Replies: 67
Views: 3135

Re: NOOBS - Why?

I've never used NOOBS. When I was a new comer, I thought the idea of "write an image to the card, and it boots" is easier than understanding an "installation program". So I followed a tutorial of dd . During the journey, forum members here told me cp could do the same thing in an easier command line...
by allfox
Mon Apr 09, 2018 11:28 am
Forum: General discussion
Topic: UART
Replies: 7
Views: 271

Re: UART

If it's about copy file from PC, the Ethernet would be easier and faster than UART. I'm not very familar with UART, but I remember if you want send binary data via UART, you would need a special protocol, as binary data need to be escaped. The name of the protocol is Zmodem. It's slow after all. I k...
by allfox
Mon Apr 09, 2018 9:02 am
Forum: General discussion
Topic: UART
Replies: 7
Views: 271

Re: UART

Could you describe more? I mean, do you connected to Pi with UART, and want to read a text file on Pi? Or you connect to Pi with something else, and want to read text from Pi's UART?
by allfox
Sat Mar 31, 2018 8:54 am
Forum: General discussion
Topic: Building the Kernel, get error during module install
Replies: 4
Views: 327

Re: Building the Kernel, get error during module install

OP is right, module installation needs sudo. You would need to include the compiler binary path in root's PATH environment variable. Mostly, I believe, that people run into this problem because they use the Raspbian official cross compiler which is git cloned into somewhere. However, you could use t...
by allfox
Wed Mar 21, 2018 6:06 pm
Forum: Advanced users
Topic: Pi 3B+ NAT capabilities
Replies: 4
Views: 479

Re: Pi 3B+ NAT capabilities

Greetings. I'm making a late reply. I would like to know how to measure the performance of ksoftirqd, if OP could tell me how he got known the bottleneck is at ksoftirqd, please. I'm asking because I'm using NIC scaling, but I don't know if it's working: https://github.com/raspberrypi/linux/blob/rpi...
by allfox
Wed Mar 07, 2018 8:24 pm
Forum: General discussion
Topic: Audio file transfer using UART
Replies: 12
Views: 1820

Re: Audio file transfer using UART

usman2323 wrote:
Wed Mar 07, 2018 3:58 pm
can i have a contact with you . i am working on similar thing . thanks
You could open a new thread.

UART is slow, audio data is huge, why put these two together?
by allfox
Sat Mar 03, 2018 11:23 am
Forum: General discussion
Topic: Raspberry PI capabilities. Would it work?
Replies: 5
Views: 573

Re: Raspberry PI capabilities. Would it work?

I don't know the exact steps nor if there is an existing solution.

But only talking about capability, YES, Pi would handle that.
by allfox
Fri Mar 02, 2018 9:09 pm
Forum: General discussion
Topic: Wireless firmware testers wanted
Replies: 80
Views: 11038

Re: Wireless firmware testers wanted

Tfontoura wrote:
Fri Mar 02, 2018 8:14 pm
How to get back to the previous (good) firmware version? Can we download the bin file from somewhere? Or is there another solution?
Try another sudo apt update and sudo apt upgrade
by allfox
Fri Mar 02, 2018 9:43 am
Forum: General discussion
Topic: Not another SD card falure
Replies: 17
Views: 1504

Re: Not another SD card falure

Spinning storage is better.
by allfox
Tue Feb 27, 2018 9:27 pm
Forum: General discussion
Topic: Virtualize os on Pi2?
Replies: 2
Views: 230

Re: Virtualize os on Pi2?

Maybe you could tell us what model the printer is. I did this kind of thing once. I virtualize Win XP under Linux to get iTunes work. I believe it's just the wrong way. I personally would change the printer to something known to work. If there is no printer known to work, for example those designed ...
by allfox
Sat Feb 24, 2018 5:09 am
Forum: General discussion
Topic: How to use toggle and push switches with the Raspberry Pi 2 to send keystrokes to a pc as keyboard commands for games
Replies: 4
Views: 426

Re: How to use toggle and push switches with the Raspberry Pi 2 to send keystrokes to a pc as keyboard commands for game

I remember that they have a new overlay which is able to translate a GPIO signal to a key stroke to Linux. Don't quite remember the name, maybe gpio-key or something. This might not yet in the normal stable kernel. You need to checkout the GitHub Kernel source tree. EDIT: this one: https://github.co...

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