Dietrich Schroff

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Dietrich Schroffhttp://www.blogger.com/profile/18397485256708620180noreply@blogger.comBlogger526125
Updated: 15 hours 23 min ago

Custom ROMs: Installing via TWRP (e.g. Prometheus ROM)

Sun, 2020-05-31 02:15
After installing TWRP and installing some ROMs via adb sideload, (or this story with my old Nexus 7) i learned that there is another way for installing Custom ROMs:

  • Boot in to recovery (Samsung: Home Button + Power + Volume Up)
  • Copy the ROM.zip to the SD card of the smartphone
  • and then follow this screenshots
Click on "Install"

Click "Select Storage"

Select your SD card

Select the ROM you want to install:

Swipe to the right

Then some of the ROMs (like Prometheus) will guide you through an installation wizard, where you can chose some options.

If you want to try Prometheus you can download it here.

Building my own Recovery ROM for a Samsung J5 2017 (j5y17lte, TWRP)

Mon, 2020-05-18 05:50
After several hours of sideloading a custom ROM and flashing a TWRP recovery image i thought the next step is to build a TWRP recovery image on my own.


So how to do that?

My startpoint was
(just search github for your device with TWRP)

But this is not the way to begin.
First you have to follow this page:
and do
repo init -u git://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-7.1
and
repo sync
Then add the j5y17lte.xml to .repo/local_manifests. After that the repo sync works but the
$ lunch omni_j5y17lte-eng
ends up with a warning:

WARNING: device/samsung/j5y17lte/omni.dependencies file not found
============================================
PLATFORM_VERSION_CODENAME=REL
PLATFORM_VERSION=7.1.2
TARGET_PRODUCT=omni_j5y17lte
TARGET_BUILD_VARIANT=eng
TARGET_BUILD_TYPE=release
TARGET_BUILD_APPS=
TARGET_ARCH=arm64
TARGET_ARCH_VARIANT=armv8-a
TARGET_CPU_VARIANT=cortex-a53
TARGET_2ND_ARCH=arm
TARGET_2ND_ARCH_VARIANT=armv7-a-neon
TARGET_2ND_CPU_VARIANT=cortex-a53
HOST_ARCH=x86_64
HOST_2ND_ARCH=x86
HOST_OS=linux
HOST_OS_EXTRA=Linux-4.15.0-88-generic-x86_64-with-Ubuntu-18.04-bionic
HOST_CROSS_OS=windows
HOST_CROSS_ARCH=x86
HOST_CROSS_2ND_ARCH=x86_64
HOST_BUILD_TYPE=release
BUILD_ID=NJH47F
OUT_DIR=/media/schroff/895337b7-c4eb-44a4-9063-00f629e5149f/omni/out
============================================

The good point: just ignore this warning and do the mka recoveryimage.

Here i got two errors:

/bin/bash -c "prebuilts/misc/linux-x86/flex/flex-2.5.39 -oout/target/product/generic/obj/STATIC_LIBRARIES/libedify_intermediates/lexer.cpp bootable/recovery/edify/lexer.ll"
flex-2.5.39: loadlocale.c:130: _nl_intern_locale_data: Assertion `cnt < (sizeof (_nl_value_type_LC_TIME) / sizeof (_nl_value_type_LC_TIME[0]))' failed.
Aborted (core dumped)
Here i followed this hint:
https://groups.google.com/forum/?hl=tr#!topic/android-building/0kzPnw3akxg
and copied the provided flex to "prebuilts/misc/linux-x86"
   cp ~/Downloads/build/flex flex-2.5.39
You have to change the name from flex to flex-2.5.39 and you have to rerun source build/envsetup.sh again.

Then i got the following errors:

bootable/recovery/gui/../twrp-functions.hpp:24:10: fatal error: 'ext4_utils/ext4_crypt.h' file not foundbootable/recovery/gui/../twrp-functions.hpp:24:10: error: 'ext4_utils/ext4_crypt.h' file not found with <angled> include; use "quotes" insteadbootable/recovery/twrp.cpp:49:10: fatal error: 'base/strings.h' file not foundThis i could resolve with:

cd bootable/recovery
ln -s ../../system/extras/ext4_utils
vi twrp-functions.hpp # add the quotes!
ln -s ../../system/core/base/include/android-base base

After that the build went through and i got a TWRP image:
-rw-rw-r--  1 schroff schroff 26937344 Mai 17 23:40 recovery.img
This ran without a problem on my J5 after a
heimdall flash --RECOVERY recovery.img



Samsung J5 2017 (aka j5y17lte) installing STOCK ROM

Sat, 2020-05-16 09:37
After installing a custom ROM (s. here) i wanted to flash the STOCK  ROM onto my smartphone again.
So what to do?

First: Download a ROM (e.g. sammobile.com)

and you will get something like
J530FXXU6CSK9_J530FDBT6CSL1_DBT.zip
this zip cannot be sideloaded. So you have to unzip and the you have:
AP_J530FXXU6CSK9_CL16642474_QB27583084_REV00_user_low_ship_meta_OS9.tar.md5
BL_J530FXXU6CSK9_CL16642474_QB27583084_REV00_user_low_ship.tar.md5
CP_J530FXXU6CSK9_CP14486297_CL16642474_QB27583084_REV00_user_low_ship.tar.md5
CSC_DBT_J530FDBT6CSL1_CL17419960_QB27658856_REV00_user_low_ship.tar.md5
HOME_CSC_DBT_J530FDBT6CSL1_CL17419960_QB27658856_REV00_user_low_ship.tar.md5
Within this you have to do a:
 for a in *md5; do echo $a;  tar -xvf $a; done
and the result should be:
boot.img   cm.bin      modem.bin  recovery.img  system.img
cache.img  hidden.img  param.bin  sboot.bin     userdata.img
or just type:

~/bin/heimdall flash --BOOT boot.img --SYSTEM system.img --CACHE cache.img --HIDDEN hidden.img --PARAM param.bin --CM cm.bin --USERDATA userdata.img --RADIO modem.bin --BOOTLOADER sboot.bin --RECOVERY recovery.img
and after nearly 10 minutes of anxious waiting you J5 boots up with the STOCK ROM again.

Corona-Homeoffice: second monitor for my laptop - portable!

Sat, 2020-05-09 15:03
After several weeks working in homeoffice and my children in homeschooling i had to increase my efficieny. And the best thing is to get a second monitor running which meets the following requirements:
  • Single Plug (for signal and power)
  • Easy movable from living room to workspace and back
  • Touchscreen would be nice
 So i decided to buy a wimaxit 15.6" portable monitor and today it arrived:




The second screen is only connected (and charged) via USB-C.
Even connecting my smartphone just works out of the box - really cool! 

My Samsung Galaxy J5 (2017) aka j5y17lte with lineage os

Sat, 2020-05-02 15:21
In the last weeks i did some tests with installing custom ROMs to my old devices:
and
The next step was to try this with my Samsung J5:
root@zerberus:~/bin# ./heimdall print-pit
Heimdall v1.4.2

Copyright (c) 2010-2017 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
PIT file download successful.

Entry Count: 29
Unknown 1: 1598902083
Unknown 2: 844251476
[.....]
File Size (Obsolete): 0
Partition Name: USERDATA
Flash Filename: userdata.img
FOTA Filename: remained

Ending session...
Rebooting device...
Releasing device interface...
But for the next step (flashing the boatloader with TWRP) i got the follwoing error:
root@zerberus:~/bin# ./heimdall flash --RECOVERY ../Downloads/twrp-3.3.1-1-j5nlte.img --no-reboot
Heimdall v1.4.2

Copyright (c) 2010-2017 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
PIT file download successful.

Uploading RECOVERY
100%
RECOVERY upload successful

Ending session...
ERROR: Failed to receive session end confirmation!
Releasing device interface...
The smartphone showed this:
  
RMM STATE: Prenormal
KG STATE: Checking
Only official released binaries are allowed to be flashed(RECOVERY)
KG = Knox Guard
RMM = Remote Monitoring and Management
(https://chimeratool.com/fr/docs/samsung-knox-guard-kg-and-remote-monitoring-and-management-rmm-unlock-functions)

I found a solution for this problem (https://www.android-hilfe.de/forum/root-custom-roms-modding-fuer-samsung-galaxy-s9-s9.3273/s9-sm-g960f-nach-android-9-kein-installieren-von-custom-recoverys-moeglich.898725.html): It just says: wait 7 days...

Grrrrr!!!!!!!

And after 7 days:
And then:

 /bin# ./heimdall flash --RECOVERY ../AndroidDevices/TWRP-3.2.3-TwrpBuilder-j5y17lte-2018-09-13_15-34.img  --no-reboot

Heimdall v1.4.2
Copyright (c) 2010-2017 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
PIT file download successful.

Uploading RECOVERY
100%
RECOVERY upload successful

Ending session...
Releasing device interface...

And after that i was able to install the lineage os plus the Google playstore:

adb sideload ../Downloads/lineage-15.1-20180510-UNOFFICIAL-j5y17lte.zip
adb sideload open_gapps-arm-8.1-j5y17lte-pico-20200418.zip The only problem:
Only an unofficial lineage version 15.1 was available for the Samsung J5 2017 aka "j5y17lte". I found one build with version 16 but there the WLAN was broken...

So this was a step back from Android 9 to Android 8.1 - but system space moved from 800MB free to 7GB free ;-)

GPay and TWRP: NFC payment not possible / forbidden

Fri, 2020-04-24 03:36
After flashing my old Samsung smartphone to TWRP (s. this posting) and before installing a custom OS, i did some tests with the original Android OS.
Everything worked but GPay refuses to work:


Your Phone can't make contactless payments
Check your phone software to see if it meets standards
Check software"
and the button "Check software" opens this popup:


Your phone doesn't meet software standards

You can't make contactless payments with this device. It may be rooted or running uncertified software. Contact your device manufacturer or visit Google Pay Help for more info.You can still use Google Pay to pay online.
OK
So GPay does not only check the OS - it checks the bootloader, too.
Even if you did not rooting/jailbreaking your OS...

My Nexus 7 (2012) is online again (with lineageos and external battery)

Thu, 2020-04-16 15:28
In 2014 i did the last update for my Nexus 7 (s. here).
It was the last update which was provided by Google for this device:
I bought the Nexus 7 seven and a half year ago and on the weekend i found the tablet in the back of the cupboard. It did not work, because the battery was completely discharged and the device refused to charge it.
Without a battery it is not possible to startup the device - only power over USB is not enough.

So i disassembled it like described here and added some cables to connect a battery from outside:

And with that modification i was able to start it  - but running Android 5 with 8GB disk space is no fun.
So i booted TWRP onto this device:

root@zerberus:~/bin# fastboot oem unlock
                                                   (bootloader) erasing userdata...
(bootloader) erasing userdata done
(bootloader) erasing cache...
(bootloader) erasing cache done
(bootloader) unlocking...
(bootloader) Bootloader is unlocked now.
OKAY [193.432s]
Finished. Total time: 193.433s

root@zerberus:~/bin#fastboot boot  ~/Downloads/twrp-3.0.2-0-grouper.img
After that i was able to install lineageOS via adb sideload.

 adb sideload  ~/Downloads/lineage-14.1-20171122_224807-UNOFFICIAL-aaopt-grouper.zip 
 adb sideload  ~/Downloads/open_gapps-arm-7.1-pico-20200415.zip
Now the device has nearly 6GB space left:

 I can use the play store and the device runs on Android version 7 - and it runs youtube movies without any interruptions...

Using a video capture usb stick with Linux / Ubuntu

Tue, 2020-04-07 13:04
Three weeks ago i ordered a video capture usb stick at banggood and today it arrived:




So will this device work with my ubuntu?

I inserted the stick on my laptop and dmesg showed:

[123483.143071] hid-generic 0003:534D:0021.0002: hiddev0,hidraw1: USB HID v1.10 Device [MACROSILICON AV TO USB2.0] on usb-0000:00:14.0-1/input4

That was all...
But there was a module missing:

modprobe uvcvideo
and after that:
[125822.751366] usb 1-1: new high-speed USB device number 19 using xhci_hcd
[125822.901442] usb 1-1: New USB device found, idVendor=534d, idProduct=0021
[125822.901449] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[125822.901454] usb 1-1: Product: AV TO USB2.0
[125822.901458] usb 1-1: Manufacturer: MACROSILICON
[125822.901478] usb 1-1: SerialNumber: 20150130
[125822.902702] uvcvideo: Found UVC 1.00 device AV TO USB2.0 (534d:0021)
[125822.902835] uvcvideo: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround.
[125822.904681] uvcvideo 1-1:1.0: Entity type for entity Processing 2 was not initialized!
[125822.904691] uvcvideo 1-1:1.0: Entity type for entity Camera 1 was not initialized!
[125822.911070] hid-generic 0003:534D:0021.0004: hiddev0,hidraw1: USB HID v1.10 Device [MACROSILICON AV TO USB2.0] on usb-0000:00:14.0-1/input4
Checking with
root@zerberus:~# ffmpeg -sources |grep video
Auto-detected sources for video4linux2,v4l2:
  /dev/video1 [AV TO USB2.0]
  /dev/video0 [HD WebCam: HD WebCam]
plus:
root@zerberus:~#  ffmpeg -list_formats all -i /dev/video1

[video4linux2,v4l2 @ 0x55b0d1ca38c0] Compressed:       mjpeg :          Motion-JPEG : 480x320 640x480 720x480
[video4linux2,v4l2 @ 0x55b0d1ca38c0] Raw       :     yuyv422 :           YUYV 4:2:2 : 480x320
/dev/video1: Immediate exit requested

Now i was able to open /dev/video1 with VLC:



The video came from a camera connected via TS832 --[5.8GHz]--> RC832...





Smartphone: Installing lineageOS + Googles Play Store (and getting 9GB system space freed up)

Sat, 2020-04-04 15:04

After installing TWRP as bootloader i was wondering, how much effort is is to install an alternative to android on my old smartphone.

Heimdall & ADB were in place (see TWRP posting) - so let's start!

I downloaded the appropriate image from https://lineageos.org/ and i did the following on my smartphone:
Click on "Wipe"
 Click on "Format Data"
 Type "Yes"
 Wait
 Step two times back and click "advanced wipe"
Choose "Cache" and "System" and swipe to the left

Step back to home screen and choose "Advanced"
 Swipe to the left
and then type:

sudo ./adb sideload ~/Downloads/lineage-16.0-20200325-nightly-a3xelte-signed.zip 

[sudo] password for schroff:

Total xfer: 1.02x                                                                                 
and then REBOOT...
(if you want a clean lineage OS)

If you want the google play store, then go to https://opengapps.org/


Download the appropriate package (i chose "pico" - https://github.com/opengapps/opengapps/wiki/Package-Comparison)

Then repeat the steps on TWRP (smartphone) for sideloading and type

sudo ./adb sideload ~/Downloads/open_gapps-arm-9.0-pico-20200403.zip

Total xfer: 1.43x



And after that the smartphone starts up with lineage OS and play store (To avoid problems: do not connect to mobile networks neither wifi within the startup wizard - this can result in a black screen and the wizard will never end).
The best thing: with Samsungs stock Android about 13GB was blocked by the system. Now only 4GB from 16GB are used. So i got additional 9GB free space. Really cool!

Using a custom bootloader for my smartphone: TWRP on Samsung Galaxy A3

Fri, 2020-04-03 15:09
I read about /e/ some days ago and i decided to install this on my old smartphone (a samsung A3).

So first: What is /e/?
https://doc.e.foundation/
So i started at

https://doc.e.foundation/devices/a3xeltexx/install
where i learned, that i have to install a custom bootloader on my smartphone. This is very good explained at /e/:

(You will find there the description how to install "heimdall" and "adb")

schroff@zerberus:~/bin$ sudo ./heimdall flash --verbose --RECOVERY ~/Downloads/twrp-3.3.0-0-a3xelte.img --no-reboot
Heimdall v1.4.2

Copyright (c) 2010-2017 Benjamin Dobell, Glass Echidna
http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is
encouraged.

If you appreciate this software and you would like to support future
development please consider donating:
http://www.glassechidna.com.au/donate/

Initialising connection...
Detecting device...
Manufacturer: "SAMSUNG"
Product: "Gadget Serial"

length: 18
device class: 2
S/N: 0
VID:PID: 04E8:685D
bcdDevice: 021B
iMan:iProd:iSer: 1:2:0
nb confs: 1

interface[0].altsetting[0]: num endpoints = 1
Class.SubClass.Protocol: 02.02.01
endpoint[0].address: 83
max packet size: 0010
polling interval: 09

interface[1].altsetting[0]: num endpoints = 2
Class.SubClass.Protocol: 0A.00.00
endpoint[0].address: 81
max packet size: 0200
polling interval: 00
endpoint[1].address: 02
max packet size: 0200
polling interval: 00
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
WARNING: Empty bulk transfer after receiving packet failed. Continuing anyway...
PIT file download successful.

Uploading RECOVERY
0%ERROR: Failed to unpack received packet.

ERROR: Failed to receive file part response!
3%
7%
10%
14%
17%
21%
25%
28%
32%
35%
39%
42%
46%
50%
53%
57%
60%
64%
68%
71%
75%
78%
82%
85%
89%
93%
96%
100%
RECOVERY upload successful

Ending session...
Releasing device interface...
and then:
For more information take a look at https://twrp.me/

Ubuntu: Disable screenlock after resuming from hibernation

Wed, 2020-03-18 14:46
There are many tutorials out there, how to disable the screen locking.

The problem with these solutions is, that still after resuming from hibernation / standby the screenlock is triggered.

To disable this behaviour you can check this:
schroff@zerberus:~/$ gsettings get org.gnome.desktop.screensaver ubuntu-lock-on-suspend
true
and then do:

gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend false
If you want to do it via gui you have to install dconf-editor
apt install dconf-editor
    Here you have to change the second last line "ubuntu-lock-on-suspend".

    Streaming a live-stream... [ffmpeg + vlc for m3u8]

    Sun, 2020-03-15 16:15
    After writing about how to stream a file to some smartphones or tablets, now the commands for streaming a live-stream to other devices.

    And like before: VLC is needed.


    But in addition to vlc you have to use ffmpeg:
    A complete, cross-platform solution to record, convert and stream audio and video.
    First thing you need is the url of the live-stream you want to re-stream. In my case is took the "Zweites Deutsches Fernsehen" (secondary channel of germany) and their url is
    https://zdf-hls-01.akamaized.net/hls/live/2002460/de/high/master.m3u8(In most of the tv channels it is something like "master.m3u8")
    m3u is the acronym for MP3 URL and m3u8 uses UTF-8.

    So the command for streaming is:
    ffmpeg -i https://zdf-hls-01.akamaized.net/hls/live/2002460/de/high/master.m3u8 -c copy -f nut - | vlc - :sout=#transcode\{vcodec=h264,scale=Auto,scodec=none\}:http\{mux=ffmpeg\{mux=flv\},dst=:8080/test\} :no-sout-all :sout-keep
     which consists of

    ffmpeg -i https://zdf-hls-01.akamaized.net/hls/live/2002460/de/high/master.m3u8 -c copy -f nut - which is piped into
     vlc - :sout=#transcode\{vcodec=h264,scale=Auto,scodec=none\}:http\{mux=ffmpeg\{mux=flv\},dst=:8080/test\} :no-sout-all :sout-keep(this is the command i build up in the last posting.)

    Have fun!

    Streaming a video file with vlc to other devices (like smartphones, etc.)

    Sun, 2020-03-15 03:29
    If you want to look a video on a tablet or smartphone (or laptop) and the file is on a server in your network, you can do this very easily with vlc.
    One big advantage: The video can be consumed by many devices - so the movie can be watched on e.g. 3 tablets...

    What do you have to do?
    Install vlc on your computer (i used a ubuntu laptop) and start vlc.
    Next step is to open the menu: media -> stream... (or press Strg-S):

    Then select the video on your disc with "+Add":
     After that click on "Stream" and this window will open:
     Click "Next" and then choose "HTTP" and press "Add"
     On the next window you have to enter the port and URL, where the devices have to connect to (in my example, the ip of my laptop was 192.168.178.39 - so the URL is 192.168.178.39:8080/test)
     Then you should select this setting and click on the wrench (="settings"):
     Here you have to select "Keep original audio track", otherwise audio will not work:

    Last window before the streaming starts:
    Copy the string to your clipboard
    :sout=#transcode{vcodec=h264,scale=Auto,scodec=none}:http{mux=ffmpeg{mux=flv},dst=:8080/test} :no-sout-all :sout-keep
     After that install vlc on your device, start it and enter the URL:
     Press "Verstanden und weiter" ;-)
     and here we go:

    If you want to skip the wizard, just open vlc with the string from your clipboard
    (you have to escape the curled brackets!):

    vlc test.mp4 :sout=#transcode\{vcodec=h264,scale=Auto,scodec=none\}:http\{mux=ffmpeg\{mux=flv\},dst=:8080/test\} :no-sout-all :sout-keep

    Squid: How to setup a proxy...

    Sat, 2020-03-14 03:35

    If you are limited on bandwidth and you want to setup several machines, using a caching proxy will speed up your installation process significantly.



    What is a caching proxy:
    https://en.wikipedia.org/wiki/Proxy_server#Improving_performance

    But proxies have some issues, that you should be aware of:
    https://en.wikipedia.org/wiki/Proxy_server#Content-control_software

    If you are sure, to use a proxy, just enter these commands:

    root@zerberus:~# apt install squid
    Reading package lists... Done
    Building dependency tree      
    Reading state information... Done
    The following additional packages will be installed:
      libdbi-perl libecap3 squid-common squid-langpack
    Suggested packages:
      libmldbm-perl libnet-daemon-perl libsql-statement-perl squidclient squid-cgi
      squid-purge resolvconf smbclient winbindd
    [....]

    Unpacking squid (3.5.27-1ubuntu1.5) ...
    Setting up libecap3:amd64 (1.0.1-3.2) ...
    Setting up squid-langpack (20170901-1) ...
    Setting up squid-common (3.5.27-1ubuntu1.5) ...
    Setting up libdbi-perl (1.640-1) ...
    Setting up squid (3.5.27-1ubuntu1.5) ...
    [....]
    To check the default configuration you can use this command:
    (to suppress the documentation and comments)

    root@zerberus:/etc/squid# cat squid.conf |grep -v \# |grep -v -e "^$"

    acl SSL_ports port 443
    acl CONNECT method CONNECT
    http_access deny !Safe_ports
    http_access deny CONNECT !SSL_ports
    http_access allow localhost manager
    http_access deny manager
    http_access allow localhost
    http_access deny all
    http_port 3128
    coredump_dir /var/spool/squid
    refresh_pattern ^ftp:        1440    20%    10080
    refresh_pattern ^gopher:    1440    0%    1440
    refresh_pattern -i (/cgi-bin/|\?) 0    0%    0
    refresh_pattern (Release|Packages(.gz)*)$      0       20%     2880
    refresh_pattern .        0    20%    4320

    After the installation the squid process should be visible and listening to its default port 3128. Check this with
    netstat -lntup
    and you will find the following lines in the output:

    tcp6       0      0 :::3128                 :::*                    LISTEN      25638/(squid-1)     
    udp        0      0 0.0.0.0:45167           0.0.0.0:*                           25638/(squid-1)    
    udp6       0      0 :::45347                :::*                                25638/(squid-1)    

    To use this proxy just enter the proxy settings inside your system settings:


    After that all of your connections are made over your proxy. You can check this via the file /var/log/squid/access.log and /var/log/squid/cache.log.

    Review: Blockchain for dummies

    Fri, 2020-02-21 16:11
    The book "blockchain for dummies" provided by IBM contains 6 chapters on 41 pages. (Download from IBM)

    The chapters 1 & 2 describe the basic of blockchain technology.
    From my point of view, this part is a bit too shallow, because there is no single formular inside this book ;-)
    But there are some nice illustrations given:

    and the differences between a public blockchain and corporate blockchains are good explained including their  consequences.

    Chapter 3 is about where companies can use blockchains. This chapter i did not understand. It is all about frictions which companies have to overcome. But these frictions are not special to blockchain (like "innovation restrictions").

    In chapter 4 some examples are shown. These examples are very universal examples, which are too abstract in my eyes.

    Chapter 5 contains information about a project of the Linux Foundation: Hyperledger.
    This is very nice opening for https://www.hyperledger.org/.

    Chapter 6 comes up with ten steps to your first blockchain application.
    Skippable.

    My conclusion: a very nice book and really ok for free. But I wouldn't spend any money on it...

    Oracle BPEL: What's up with it?

    Fri, 2020-01-31 15:22
    Nearly 20 years ago there was a new standard for modelling business processes: BPEL (https://en.wikipedia.org/wiki/Business_Process_Execution_Language)
    Oracle bought Collaxa and released the Oracle BPEL Process Manager.
    In 2009 i wrote some posts over tutorials, which where from collaxa and which were very useful for starting with Oracle BPEL product:
    http://dietrichschroff.blogspot.com/search?q=lost+collaxa

    And what is left today?

    The product is still listed on Oracle homepage:

    And there is a section with some "news":


    But the version number 10.1.3.4 is not really somehing new and if you open the white paper you will see:

    I think a whitepaper from 2014 is not really something new. 

    If you take a look on the BPEL specification at oasis (http://docs.oasis-open.org/wsbpel/2.0/OS/wsbpel-v2.0-OS.html), you can see, that there was no update to the BPEL standard for more than 10 years. 

    It is very sad, that this concept of modelling processes in a graphical way was unsuccessful...

    Oracle VM Server: OVMAPI_2005E and OVMEVT_003503D_000

    Sat, 2020-01-25 07:16
    In my OVM environment i was trying to delete a server from a pool and this did not work. The error i got signalled was:
    OVMAPI_2005E "[ServerDbImpl] xx:yy:zz:... (oraclevm)" contains a component "xx:yy:zz:..." in error. Error event: server.cluster.failure., Summary: Server Cluster Failure, Description: Failed to leave cluster OVMEVT_003503D_000 Server reboot is required.. I rebootet the server: still the same error.
    I rebootet the ovm manager: still the same error.

    Then i realized, that there was a red cross at my server:

    The solution was: Select events from the drop down for this server:

    There i had to "Acknowledge" the events and after that i was able to remove the server without any further error...

    Oracle VM Server: Pool is locked forever

    Mon, 2019-12-23 15:27
    If you are using Oracle VM Server it is possible that you are hitting the following problem:

    After changing something on a server pool the pool gets locked and the lock stays there:
    Even a reboot of your OVMM (oracle vm manager) does not remove the lock.

    The solution can be very easy:
    Just edit the pool and add (or change) the description.

    This edit triggers an update and removes the lock. I think every other change would do the job, but this is a minimal change, which solves the problem...

    Hopefully there will be an update, so this problem will disappear in future versions.


    Microsofts Visual Studio Code on Linux

    Tue, 2019-12-10 14:04
    On the last weekend i was wondering, what kind of IDE i can use for doing some small programs with javascript. My first idea was eclipse, but a friend mentioned Microsofts Visual Studio Code:
     So i opened https://code.visualstudio.com/ and got
    So i downloaded the .deb and after a dpkg -i of that file i was able to run Visual Studio Code on my Linux machine:
    schroff@zerberus:~$ code 
    The startup was amazing fast - less a second.

    Within Visual Studio Code it is very easy to install some extensions:

    Running a small javascript program is very easy. I just entered these lines and without any further configuration running the program or debugging was no problem:


    Linux ser2net: no connection to /dev/ttyUSB0

    Sun, 2019-12-01 13:17
    If you are running some java application on a Linux box (especially ARM architecture) and this application accesses the serial interface (/dev/ttyUSB0, /dev/ttyUSB1 or just /dev/ttyX), then a easy way to do this, is running ser2net.

    For all who are not familiar with the serial port:
    https://en.wikipedia.org/wiki/Serial_port



    But there is one tricky thing, you have to consider when using ser2net:

    Inside ser2net.conf you will find some lines like this here:

    15000:raw:0:/dev/ttyUSB0:9600 8DATABITS NONE 1STOPBIT
    This means: on port tcp 15000 you can access the serial port /dev/ttyUSB0 (if you have a USB to serial adapter in place).

    If this does not work, check the ports with

    root@ubuntu:/home/ubuntu/dfld# netstat -lntup |grep ser2net
    tcp6       0      0 :::15000                :::*                    LISTEN      1361/ser2net       
    As you can see, it only listens on TCP6. So you have to reconfigure this to


    127.0.0.1,15000:raw:0:/dev/ttyUSB0:9600 8DATABITS NONE 1STOPBIT
    If you only want to access this on localhost (which is very nice security enhancement ;-) ).
    And after a restart of ser2net everything works like expected:


    root@ubuntu:/home/ubuntu/dfld# netstat -lntup |grep ser2net

    tcp        0      0 127.0.0.1:15000         0.0.0.0:*               LISTEN     

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