Dietrich Schroff

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Dr. Dietrich Schroff
Updated: 13 hours 2 min ago

FritzBox 7270: CLIP stops working after upgrading to FritzOS 6.05 (problem solved)

Wed, 2014-06-11 00:02
After upgrading to FritzOS 6.05 CLIP stopped working with my analog phone.
The settings looked quite ok: (Telefonie -> Telefoniegeräte -> bearbeiten -> Merkmale des Telefoniegeräts)

This basic feature was certainly not shipped without testing. So this has to be a problem of data/parameter migration.
After unchecking CLIP, doing a reboot and checking the box again CLIP, it worked like before...

Mounting VMWare-Volumes/Disks with Debian

Tue, 2014-05-20 15:30
Some time ago a vmware server did not recognize any more a data disk. This disk was formatted with vmfs v3 (enter the vmware server via ssh and type mount..). First thing i did, was creating an image of this disk, to play around without any danger of data loss.

There is a good article how to mount vmfs, but on debian i had to install the package otherosfs.

After i installed this package, i got the following error:

root@debian:/tmp# vmfs-fuse image /mnt/vm
VMFS VolInfo: invalid magic number 0x00000000
VMFS: Unable to read volume information
Trying to find partitions But: Do not worry about this error message. The image was mounted on /mnt/vm and accessible without any problem...

Ubuntu upgrade to 12.04: grub timeout does not work anymore

Sun, 2014-03-30 14:11
After doing the upgrade and solving some issues with my screen-resolution, another grub problem hit me:
The timeout for booting the standard kernel did not work anymore.
Inside /etc/default/grub
GRUB_TIMEOUT=10and update-grub, grub worked like
 GRUB_TIMEOUT=-1If you need a  good manual  just look here, but this does not help me, too.

After some tries, i did the following:

In /boot/grub/grub.cfg i changed from
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=-1
  if [ x$feature_timeout_style = xy ] ; then
    set timeout_style=menu
    set timeout=10
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=-1
  if [ x$feature_timeout_style = xy ] ; then
    set timeout_style=menu
    set timeout=10
fiThis works, but i have to redo the change everytime update-grub is used...

Ubuntu upgrade to 12.04: screen only works with 1024x768

Sun, 2014-03-30 13:57
After upgrading a laptop-system to 12.04 (precise pangolin) X only starts with a resolution of 1024x768 and not with 1366x768.
I followed many postings and tried many things:
  • add new resolution with xrandr (here)
  • create a xorg.conf file (here)
  • add new drivers (here)
  • ...
But there was only one thing wrong: /etc/default/grub

After changing the following line everything worked:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.modeset=0 to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"(i added i915.modeset=0  because with the older ubuntu version hibernate does not work and this configuration fixed it. [link])

Telegram on two devices...

Tue, 2014-02-25 14:32
After trying Whatsapp on 2 devices without success, i tried the same thing with telegram. Telegram says about multiple devices:

So let's see...
Registering the mobile phone was straight forward: a SMS with a verification code and that's it.
Registering was easy: just another SMS
And after entering the code on the tablet i got the following message on my mobile phone:
After that every conversation or more precise: every unsecure conversation is broadcasted to all of your devices. That means, you can switch over from phone to tablet without loosing your context... really cool!

Smart Meter@Home: Fritz!Powerline 546E - really smart?

Tue, 2014-02-18 14:15
Everyone is talking about Smart Meter - is it possible to get in touch with this topic by buying a Fritz!Powerline 546E?

The key points of Smart Meters according to wikipedia are:
  • real-time or near real-time sensors
  • power outage notification
  • power quality monitoring 
  • collect, and analyze energy usage
What is supported by the 546E?
  • power outage notification: no way without a battery ;-)
  • real-time or near real-time sensors: one measurement per minute
  • power quality monitoring: voltage monitoring
  • collect and analyze: 

But there are some shortcomings:
  • graphs and data only local on 546E, no integration to any central server, not even to a Fritz!Box (because of a missing DECT interface)
  • configuration as WLAN repeater not described in the manual (only powerline)
  • export via web frontend limited to 5 minute-intervals only 24 hours
  • automated export only via E-Mail and limited to this:


Whatsapp on 2 devices: "does not work, tell why!"

Tue, 2014-01-28 13:58
After nearly everyone of my friends is using whatsapp, it was overdue to download this app.
Why is this app used by everyone? What's cool about this app?
  • You have to do nothing after the download except this sms-verification
  • No account creation
  • No new password (or reuse another one <- li="" nooo="">
  • No need for searching addresses
  • You do not have to take care about your contact list
  • Just start messaging
Why does this work? Whatsapp uses your phonenumber to build the account identifier. The app scans your phone address book and builds its own contact list. Fine.


Not at all: If you want to add whatsapp on a second device with no sim card (e.g. your tablet), you can find several instructions but: after adding whatsapp to this device, whatsapp on your phone does no longer work...
Whatapps says:
Your WhatsApp account can only be verified with one number, on one device.
If you attempt to frequently switch your WhatsApp account between different devices, at a certain point, you may be blocked from re-verifying your account. So please do not repeatedly switch between different devices.
WhatsApp Support TeamFinally i would say: The biggest advantage is also the biggest disadvantage. Using the phonenumber as account id makes everything easy but prevents the usage of more than one device....

Android Update: 4.4.2

Sat, 2013-12-14 04:16
Only two week after upgrading to Android 4.4 the next update was available:
And like all other minor upgrades: no information about the updates....
If you compare the information you notice the kernel upgrade from 3.1.10-gee1a0b2 to 3.1.10-g4776c86.
For a complete history of all updates visit this posting.

Adding Statcounter to Contao-CMS

Sun, 2013-12-08 03:47
If you are running a Contao based website and you want to add the snippet for statistics, there is no manual how to to this. I tried some different things, and this was my solution:

  • Create a file name counter.html on your webserver on toplevel of the Contao system (htdocs or something equivalent).
  • Put the Statcounter snippet in this file
<-- Start of StatCounter Code for Default Guide -->
(script type="text/javascript")
var sc_project=NNN; 
var sc_invisible=1; 
  • Then add the following next to the last line inside index.php:
include 'counter.html';
  • After that you will be able to get your statistics via

    Android Update: 4.4

    Tue, 2013-12-03 14:44
    After nearly everyone got the update, my device came up with this tiny icon:
    And here we go:

     If you follow the link you will get the following information:
    • KitKat 4.4: Smart, simple, and truly yours 
    • and several other enhancements of version 4.4
    And here the system information after the update:
    For a complete history of all updates visit this posting.

    Windows 8: create system image fails with 0x80070001

    Sat, 2013-10-26 03:06
    Last week i tried to create a system image with the built-in backup-tool from Windows 8. It sounds very easy:
    • connect an usb storage to your computer
    • start system image creation (look here)
      But then i got this error: 0x80070001

    After googling around i found the following solution:
    But there you get something with junctions and FAT-filesystems... This did not solve the problem...
    The solution was very easy: I had truecrypt running and this created an additional mount point. After stopping truecrypt the system image was created without any error...

    Windows 8.1: Update via Store

    Thu, 2013-10-17 13:25
    Yesterday i did the update from Windows 8 to Windows 8.1 via Windows App Store. Here some screenshots:

    The Download took more than 1 hour...
    The some configurations before the reboot:
    But after the reboot it took more than 15 minutes until i was able to login again. And that without any progress bar - just several messages like configuring applications and more than once percentage indicators running from 0% to 100% and then the next one...

    Android Update: 4.3

    Sat, 2013-08-03 14:38
    This week my Nexus 7 came up with this notification:
    I read about that Google launched 4.3, so i tapped on this notification and:
    And this time Google provides some information about this release.
    One really nice thing is, that with 4.3 it is possible to create restricted user accounts and you can grant these accounts access to specific apps, which you already installed. This is exact the thing you need, if you want to create accounts for your children without app store access and without creating them e-mail accounts....

    Windows Surface RT: There is a desktop?!

    Mon, 2013-06-10 14:21
    Last week i had the opportunity to use a Windows Surface RT tablet. For several month i am using a windows 8 laptop, which is equipped with a touchscreen. So i am used to the new tiles interface and i knew at least on laptops, you have the desktop-applications and the "tiles"-applications.
    I was curious, how it feels to work without having "two worlds" of applications on a device...
    But it was for me big suprise: If you install Microsoft Office on a RT device, you get the desktop back:
     On a tablet with a display size with 10.6 inches (27cm)? I tried to write a document and it wasn't easy to hit the right icons...
    By saving the document it was astonishing, that i got a file chooser. From my Nexus 7 i was used to get no folder structures or similar things:
    There are two problems with this desktop applications: If not in full-screen mode, you have to work with really small windows and resizing is very difficult and
     the applications are not shown in the application bar:
    They are all summarized with desktop... There is no way to switch directly to your word application or powerpoint.  You have to move the desktop und then choose your Office application....

    Dual-Boot on UEFI PCs: Booting Ubuntu only works randomly

    Wed, 2013-04-24 14:51
    In my posting about using ubuntu on a Windows 9 laptop, i ended with:
    But now rebooting works like expected (with Ubuntu and Windows 8).

    Linux and UEFI: Files, Mountpoints, Commands...

    Mon, 2013-04-22 14:28
    With Windows 8 secure boot is used. That means if you want to add a Linux kernel, this kernel has to be signed. After installing Ubuntu on a Windows 8 machine, here the directory listing of the /boot directory:
    -rw-r--r-- 1 root root   844882 Okt  9  2012 abi-3.5.0-17-generic
    -rw-r--r-- 1 root root    17402 Apr 21 18:48 boot.efi.txt
    -rw-r--r-- 1 root root        0 Apr 21 18:49 boot.txt
    -rw-r--r-- 1 root root   147884 Okt  9  2012 config-3.5.0-17-generic
    drwxr-xr-x 4 root root      512 Jan  1  1970 efi
    drwxr-xr-x 5 root root     4096 Apr 21 18:45 grub
    -rw-r--r-- 1 root root 23040071 Apr 21 16:33 initrd.img-3.5.0-17-generic
    -rw-r--r-- 1 root root   176764 Jan  3 23:48 memtest86+.bin
    -rw-r--r-- 1 root root   178944 Jan  3 23:48 memtest86+_multiboot.bin
    -rw------- 1 root root  2901710 Okt  9  2012
    -rw-r--r-- 1 root root  5129040 Okt 17  2012 vmlinuz-3.5.0-17-generic
    -rw-r--r-- 1 root root  5130968 Okt 17  2012 vmlinuz-3.5.0-17-generic.efi.signed
    The directory grub contains all files related to grub/grub2. The directory efi is a mountpoint:
    /dev/sda3 on /boot/efi type vfat (rw)
    /dev/sda3         258048   48975    209073  19% /boot/efi
    This partition is a partition, which was created from Windows 8 and contains the following:


    Using Ubuntu on a Windows 8 Laptop: because of UEFI more problems as expected

    Sun, 2013-04-21 14:19
    Today i tried to install Ubuntu on a Windows 8 Laptop. First thing: you have to use 12.04 or greater because Windows 8 uses secure boot with UEFI.
    But after the first boot with a USB-stick i got:
    (initramfs) Unable to find a medium containing a live file system?? - If you ask google you get something like: Do not use a usb 3.0 port... Great... There is no usb 2.0 port on my device....
    So just trying around with a usb 2.0 hub  - does not work
    Looking inside BIOS i found XHCI:
    And after that Ubuntu is installed without any problems... (hmm - that is not really true: resizing the Windows 8 partition could not be done via Ubuntu installer - but just do this in Windows 8 - this will work without any problems).
    Ok - end of this posting? Unfortunately not, because Windows 8 does not boot anymore.
    I think this is ok ;-)
    Asking Google gives the following solution: Just use Boot-repair.
    sudo bash
    add-apt-repository ppa:yannubuntu/boot-repair
    apt-get update
    apt-get install boot-repair
    And after that the grub menu looks like this:
    But now rebooting works like expected (with Ubuntu and Windows 8).
    [If you still have problems that booting ubuntu does not work on every startup, read here]

    Using Virtualbox images with Hyper-V

    Thu, 2013-03-21 15:39
    In 2008 i wrote about using vmware images with virtualbox. To migrate a host from virutalbox to Hyper-V, you have to do nearly the same, but you have to convert the hdd:
    C:\Users\schroff>"\Program Files\Oracle\VirtualBox\VBoxManage.exe" clonehd
    "c:\Users\schroff\VirtualBox VMs\Debian64-DS\Debian64-DS.vdi"
    "c:\Users\schroff\VirtualBox VMs\Debian64-DS-Hyper-V"\Debian-DS.vhd
    -format vhd0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
    Clone hard disk created in format 'vhd'. UUID: c42129a8-c145-4a50-908c-023c8ed2b711

        Hyper-V: Compile Linux Kernel with Microsoft device drivers

        Thu, 2013-03-21 14:41
        After knowing, that running a linux inside Hyper-V is only working with the "legacy" network adapter (look here), i was trying to build a kernel with the drivers (Microsoft has added the drivers into the Linux kernel versions >2.6.32).
        There is one nice tutorial out there:
        • IT FROM ALL ANGLES: Hyper-V Guests: Compile Linux Kernel 2.6.32 on Debian 
        But the menus of menuconfig have changed with kernel version 3.0. Microsofts Hyper-V kernel modules are no longer located inside the staging section. They can be found here:
        Device Drivers --> Network device support -->
        Device Drivers -->  Microsoft Hyper-V guest support -->
        Device Drivers --> HID Support --> Special HID Drivers -->

        All other steps work like described in IT FROM ALL ANGLES: Hyper-V Guests: Compile Linux Kernel 2.6.32 on Debian.
        Microsoft offers a ISO-image for installing the kernel modules for some special kernel version for this linux distributions:
        • Red Hat Enterprise Linux 5.7, 5.8, 6.0-6.3 x86 and x64
        • CentOS 5.7, 5.8, 6.0-6.3 x86 and x64

        The ISO-image can be downloaded from this location.

        Note: If you try to build the kernel in you virtual machine, you need at least 6GB in /usr/src for compiling your kernel...

        Hyper-V: Installing a debian linux in a virtual machine - trouble with the (non legacy) network adapter

        Sun, 2013-03-17 15:03
        First try with a virtualization solution like Hyper-V is to install a guest. So let's try debian linux.
        The installer runs through this points:
        1. Name & path of the virtual machine
        2. RAM
        3. Network (how to configure a virtual switch with internet connectivity or how to configure internet connectivity with NAT)
          at this point you have to choose no connection (i will explain this later)
        4. Create a hdd
        5. The summary should look like this:
        Next step you have to open the configuration of this virtual machine. There you can see a network adapter with the following properties:
        Bandwith management? This sounds really good. There are two types of network adapters:

      1. A network adapter requires a virtual machine driver in order to work, but offers better performance. This driver is included with some newer versions of Windows. On all other supported operating systems, install integration services in the guest operating system to install the virtual machine driver. For instructions, see Install a Guest Operating System. For more information about which operating systems are supported and which of those require you to install integration services, see About Virtual Machines and Guest Operating Systems (
      2. A legacy network adapter works without installing a virtual machine driver. The legacy network adapter emulates a physical network adapter, multiport DEC 21140 10/100TX 100 MB. A legacy network adapter also supports network-based installations because it includes the ability to boot to the Pre-Execution Environment (PXE boot). However, the legacy network adapter is not supported in the 64-bit edition of Windows Server 2003. 
      3. And now think about, for which type of network adapter the standard kernel has a kernel modul (or you can get sources for)... Right. Only the legacy adapter.
        So you have to delete the network adapter and add a legacy network adapter. After this step, your virtual machine should look like:
        The bandwidth management is gone, but your kernel can use the tulip module and your network is working... Here you have to choose a virtual switch, which you can create like described in these two postings:  how to configure a virtual switch with internet connectivity or how to configure internet connectivity with NAT.

        It is not really suprising, that Microsoft adds as default to each new virtual machine a network adapter, which only works on a few linux distributions. You can download drivers from microsoft via this page (scroll down to "integration services"). But to add the default each for every new virtual machine, so that you have to delete this one and add the "legacy" adapter.

        But after knowing this, it is no problem to install debian linux (or any other linux) onto your Hyper-V.