Author Archives: admin

Prevent hard disk drive from sleeping/spinning down/power saving

Modern hard drives have this annoying power saving feature of spinning down when disk is not in use for a couple of minutes. This often results in a few seconds pause when accessing files, game freezing until disk spins up and so on.

To fix it, first thing you wanna check is a setting Turn off hard disk after in advanced power options (Fig. 1).

Fig. 1 Advanced power settings

Make sure it is set to 0. After saving settings, give it a go – if it helps, then great, problem solved. However usually this is not enough, because modern HDD’s have hardware level power saving features which ignore this Windows setting. My go-to tool to prevent drives from sleeping is CrystalDiskInfo (just get Standard edition). Upon installing it, select Function -> Advanced Feature -> AAM/APM Control from top bar menu, select your hard drive(s) and click on Disable under Automatic Acoustic Management (AAM) and Advanced Power Management (APM) sections (if applicable) (Fig. 2).

Fig. 2 AAM/APM Control

Then check option Function -> Advanced Feature  -> Auto AAM/APM Adapation. Lastly check Function -> Startup to make CrystalDiskInfo run on Windows logon (Fig. 3).

Fig 3. Menu

Raspberry Pi NFS server and Windows client

Introduction

Microsoft supplied NFS client is available only in the Enterprise and Ultimate Windows editions. In this article I’ll explain how to setup and run NFS server on the Raspberry Pi 3 computer running Raspbian operating system and connect to it from Windows 10 Home client (everything should work with other Windows versions and editions).

Raspberry Pi server

titulinis

Mounting disc

Connect disc to the Raspberry Pi and run command fdisk -l. Check the name your drive got:

fdisk_eng

Create mounting point:

sudo mkdir /media/transcend

Connected drive is NTFS formatted, so we make sure that NTFS read – write driver is installed:

sudo apt-get update

sudo apt-get install ntfs-3g

Add this entry to the /etc/fstab file:

Restart Raspberry Pi and create a new folder where you’ll keep your NFS share:

mkdir /media/transcend/NFS

Setting up NFS server

Install:

sudo apt-get install nfs-common nfs-server

Add this entry to your /etc/exports file:

exports

192.168.8.0/255.255.255.0 means that NFS server will accept connections from local IP addresses in range of 192.168.8.1 – 192.168.8.254. Option insecure is added because otherwise Windows clients can’t connect.

Windows client

Download NFS Windows client binaries from here.

Extract them and follow these steps:

  1. Install (if not installed) vcredist*.exe libraries.
  2. Double click nfs41_driver.cer file, select Install Certificate and put it in Trusted Root Certification Authorities store.
  3. Open cmd.exe as administrator.
  4. Run install.bat file.
  5. Copy config files:
    1. mkdir C:\etc
    2. copy etc_netconfig C:\etc\netconfig
    3. copy ms-nfs41-idmap.conf C:\etc\
  6. Allow windows to load test-signed drivers:
    bcdedit /set testsigning on
  7. Restart your PC.
  8. Disable the DFS client:
    1. Run regedit and navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Mup
    2. Add DWORD value named DisableDfs with value 1.
    1. If there is none, add DNS suffix: dns_suffix
    2. Reboot your PC.
  9. Test NFS client by running:
    nfsd_debug.exe --noldap --uid 1000 --gid 1000 -d 3
  10. If client didn’t crash, open other command window and mount NFS share as Z drive:
    nfs_mount.exe Z: 192.168.8.103:\media\transcend\NFS

    where 192.168.8.103 is Raspberry Pi IP address.

It works:

veikia

If trying to mount NFS share you are getting similar error:

failed_mount

but NFS server is running and restarting it

sudo /etc/init.d/nfs-kernel-server restart

fixes the problem, it’s possible that nfs-kernel-server is starting earlier than external drive is mounted. To fix this you can delay nfs-kernel-server starting for, say 10 seconds, by editing /etc/init.d/nfs-kernel-server file and adding sleep 10 line after start section:

sleep_nfs_kernel

Running and mounting automatically

If you made sure that everything is running, run command line as administrator, return to extracted NFS client folder and install NFS client as a service:

nfsd.exe -install

Then run services.msc, find pnfs client entry and change its startup type to automatic:

servicesmsc

To auto-mount NFS share, run Task Scheduler tool, in the left pane select Task Scheduler Library and create a new task by clicking Create Task in the right pane. Give your task a name, in the Triggers tab create a trigger which will run on system startup with 30 seconds delay, in the Actions tab create Start a program action, which will point to a script with similar command:

C:\Users\User\Desktop\ms-nfs41-client-x64\nfs_mount.exe Z: 192.168.8.103:\media\transcend\NFS

In the Conditions tab remove the check from start the task only if computer is on AC power.

taskscheduler

Press OK.

Next time you restart your Windows PC, NFS client will run and mount NFS share automatically.

Sources

  1. Raspberry Pi: How to Create an NFS Server
  2. NFSv4.1 Client for Windows
  3. NFSv4.1 Client for Windows (Mailing list)
  4. nfs-kernel-server starts too early

Boscam HD19 and Raspberry Pi

There seems to be only one way to feed live video from Boscam HD19 FPV camera to Raspberry Pi over wire. To do that you’ll need composite AV to USB capture card. The one I had lying around is called KWorld VS-USB2800D Composite/S-Video to USB 2.0 (see Pic 1 and 2).

KWorld VS-USB2800D

Pic 1. KWorld VS-USB2800D front side

KWorld VS-USB2800D

Pic 2. KWorld VS-USB2800D back side

Connect Boscam camera to capture card with supplied mini USB to composite AV cable. Insert supplied multifunctional port’s power cable and connect it to 12 V battery (as per Boscam’s specification). I used Turnigy 3S 11.1 V battery which seems to do the job. See pics bellow.

Pic 3. Boscam HD19 with composite and power cables connected

Pic 3. Boscam HD19 with composite and power cables connected

Pic 4. Turingy 3S 11.1 V battery

Pic 4. Turnigy 3S 11.1 V battery

Pic 5. Everything's connected

Pic 5. Everything’s connected

Connect capture card to Raspberry’s USB port (Pic 6).

Pic 6. And... It's a mess

Pic 6. And… It’s a mess

Turn on your Boscam camera by holding its power button and start Raspberry. If you’re lucky Raspberry will detect your capture card on boot and it’ll be ready to use. You can quickly test it with software like guvcview. You can find an incomplete list of supported devices here.

In my case, even though everything was detected, all I got was black screen. The problem was that KWorld’s capture card has two inputs: S-Video and composite and it defaults to using S-Video.

To fix this I listed available channels:

enum_channels

Pic 7. Listing available channels

and selected composite channel:

select_channel

Pic 8. Selecting channel

It works!

Pic 7. guvcview works

Pic 9. guvcview works

Making Samsung Galaxy S2 i9100 and Samsung Galaxy Note 10.1 N8000 faster

I bought Samsung Galaxy S2 & Samsung Galaxy Note 10.1 couple of years ago and for the better part of the last half a year both devices became unbearably slow. I went through the usual motions of cleaning junk and cache and memory but nothing helped, so I just kinda written of bad performance as a case of “applications becoming more bloated and device performance staying the same”. However, recently I read that Android didn’t have TRIM support until 4.3 version (more about this here). Problem is, that highest supported version of Android by Galaxy S2 and Galaxy Note 10.1 is 4.1.2. I didn’t want to try custom roms, so I tried fixing my performance using third party software Trimmer (fstrim). Before trying this program you need to have your device rooted, you can read about it here (Galaxy S2) and here (Galaxy Note 10.1).

Running Trimmer (fstrim) software alleviated performance problems significantly.

P. S. There is a chance to brick your device by either rooting or running trimming software, so do it at your own risk.

Compiling bgslibrary demo program

Before beginning make sure you have OpenCV >= 2.4 installed.

Copy the following demo code into main.cpp:

#include <iostream>
#include <cv.h>
#include <highgui.h>

#include “package_bgs/FrameDifferenceBGS.h”

int main(int argc, char **argv)
{
CvCapture *capture = 0;
capture = cvCaptureFromCAM(0);

if(!capture){
std::cerr << “Cannot initialize video!” << std::endl;
return -1;
}

IBGS *bgs;
bgs = new FrameDifferenceBGS;

IplImage *frame;
while(1)
{
frame = cvQueryFrame(capture);
if(!frame) break;

cv::Mat img_input(frame);
cv::imshow(“Input”, img_input);

cv::Mat img_mask;
cv::Mat img_bkgmodel;

// by default, it shows automatically the foreground mask image
bgs->process(img_input, img_mask, img_bkgmodel);

//if(!img_mask.empty())
// cv::imshow(“Foreground”, img_mask);
// do something

if(cvWaitKey(33) >= 0)
break;
}

delete bgs;

cvDestroyAllWindows();
cvReleaseCapture(&capture);

return 0;
}

Copy package_bgs directory from bgslibrary into directory containing main.cpp file and create a new folder named config in the same directory.

Compile

g++ -c `pkg-config opencv –cflags` main.cpp package_bgs/FrameDifferenceBGS.cpp

Check library paths

pi@raspberrypi ~ $ cat /etc/ld.so.conf.d/opencv.conf
/usr/local/lib/

pi@raspberrypi ~ $ sudo ldconfig -v

Link

g++ -o out `pkg-config opencv –libs` main.o FrameDifferenceBGS.o

Execute

./out