Friday, 26 May 2017

More on Seyed Hossein Ahmadpanah

This guy is really good! Plagiarised from Niklaus Wirth even!
Here is Seyed's data structures book Seyed's book

And here is from Wirth's book at Algorithms and Data Structures

I should be honoured to be considered worth plagiarising in such company!

Plagiarism by Seyed Hossein Ahmadpanah

I've had an a book online for many years "Network Programming with Go" under a Creative Commons license which allows copies but does not allow change of copyright to another person. It is now being published by APress.

It was pointed out to me that Seyed Hossein Ahmadpanah has self-published a book "Go for Network" which is a complete ripoff of my book. Well, he did change one thing: the name of the author from me to him! Checking up, this guy is really prolific: according to he has published 24 books!

A list of his magnificent achievements is given below. I haven't checked many of them, but in addition to mine, the Start Linux book appears to be stolen from Alex Carr Dive into Linux
If you know the original authors of any of these books, please let them know!

Data Structure

 The modern digital computer was invented and intended as a device that should facilitate and speed up complicated and time-consuming computations. In the majority of applications its capability to store and access large amounts of information plays the dominant part and is considered to be its primary characteristic, and its ability to compute, more
By Seyed Hossein Ahmadpanah

Learn CSS3

 If you've been a web developer for any length of time, then CSS won't be strange to you. You might, however, be wondering what the fuss over CSS3 is all about. Just like the new HTML 5 specifications, CSS3 (or CSS Version 3, to be more precise) is the latest set of specifications designed to mold, shape, and define just what capabilities the newest version of CSS more
By Seyed Hossein Ahmadpanah

Go for Network

 You can't build a system without some idea of what you want to build. And you can't build it if you don't know the environment in which it will work. GUI programs are different to batch processing programs; games programs are different to business programs; and distributed programs are different to standalone more
By Seyed Hossein Ahmadpanah

How to Start Java Programming

Why another book on Java? Why a book on Java and Linux? Isn’t Java a platform-independent system? Aren’t there enough books on Java? Can’t I learn everything I need to know from the Web?
By Seyed Hossein Ahmadpanah

How Operating Systems Work

 All desktop computers have operating systems. The most common are the Windows family of operating systems developed by Microsoft, the Macintosh operating systems developed by Apple and the UNIX family of operating systems (which have been developed by a whole history of individuals, corporations and collaborators) more
By Seyed Hossein Ahmadpanah

Proactive Cyber Defense: Security for Government

Proactive cyber defense in Government relates to the way a company is run and managed in order to ensure its well-being. All of a company’s stakeholders are basically players as far as good Government is concerned, but the responsibility and accountability for it starts with its Board of Directors and Senior more
By Seyed Hossein Ahmadpanah

Data Mining for Big Data

The most commonly accepted definition of “data mining” is the discovery of “models” for data. A “model,” however, can be one of several things. We mention below the most important directions in modeling.
By Seyed Hossein Ahmadpanah

Why Unit Test

By Seyed Hossein Ahmadpanah

Start Wordpress

Start WordPress Right Now !
By Seyed Hossein Ahmadpanah

Start Linux

Linux is a Unix-like open source operating system. At the core of the operating system is the Linux kernel. It acts as the intermediary between the applications which run in the operating system and the underlying hardware.
By Seyed Hossein Ahmadpanah

Start Php

 PHP is a powerful programming language that lets you build dynamic Web sites. It works well on a variety of platforms, and it's reasonably easy to understand.
By Seyed Hossein Ahmadpanah

Start Bootstrap

 Bootstrap, quite simply, puts the power of design and UI layout back in the developer’s hands, leaving things in a nice, clean, easy-to-maintain state that can then be passed to a front-end graphic designer whose job it is to make things shine.
By Seyed Hossein Ahmadpanah

What Is Git ?!

Git is an open-source version control system known for its speed, stability, and distributed collaboration model. Originally created in 2006 to manage the entire Linux kernel, Git now boasts a comprehensive feature set, an active development team, and several free hosting more
By Seyed Hossein Ahmadpanah

What Is Angular.js?! 

Angular.js is an open-source JavaScript framework developed by Google. It gives JavaScript developers a highly-structured approach to developing rich, browser-based applications which leads to very high productivity. If you are using more
By Seyed Hossein Ahmadpanah

Full Android Guide: Advanced

 Android has grown from nothing to arguably the world’s most popular smartphone OS in a few short years. Whether you are developing applications for the public, for your business or organization, or are just experimenting on your own, I think you will find Android to be an exciting and challenging area for more
By Seyed Hossein Ahmadpanah

Start Mongodb

Most of this book will focus on core MongoDB functionality. We’ll therefore rely on the MongoDB shell. While the shell is useful to learn as well as being a useful administrative tool, your code will use a MongoDB driver. This does bring up the first thing you should know about MongoDB: its more
By Seyed Hossein Ahmadpanah

Full Android Guide: Intermediate

By Seyed Hossein Ahmadpanah

Full Android Guide: Beginner

By Seyed Hossein Ahmadpanah

Start Node.js

Node - or Node.js, as it is called to distinguish it from other "nodes" - is an event-driven I/O framework for the V8 JavaScript engine. Node.js allows Javascript to be executed on the server side, and it uses the wicked fast V8 Javascript engine which was developed by Google for the Chrome more
By Seyed Hossein Ahmadpanah

Start SQLNetwork

This book will cover the basics of SQL, and should help introduce beginners to SQL concepts. It is also a good documentation source when forgetting how the basic SQL syntax works.
By Seyed Hossein Ahmadpanah

Start Js!

JavaScript (JS for short) is the programming language that enables web pages to respond to user interaction beyond the basic level. It was created in 1995, and is today one of the most famous and used programming languages.
By Seyed Hossein Ahmadpanah

Start Go!

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
By Seyed Hossein Ahmadpanah

Start Python 3!

This is a simple book to learn Python programming language, it is for the programmers who are new to Python.
By Seyed Hossein Ahmadpanah

Start Ruby !

 Start Ruby! will help you begin programming in Ruby
By Seyed Hossein Ahmadpanah

Friday, 22 May 2015

Linux graphics on Gigabyte Brix i7 5500

I've been installing and running Linux on sooooo many computers for years and it hasn't been a problem for sooooo many years. I thought it was easy now :-(. The Gigabyte Brix GB-BXi7H-5500 has got me. (But in the end I won). The problem is crazy graphics display when trying to use any of the desktop live installs, making Linux apparently un-installable.

It only has HDMI output and mini DisplayPort. I started with Ubuntu 14.04. Ho hum, the HDMI driver didn't work and I just got garbage on the screen DURING THE INSTALL PROCESS. Same with some other distros: if they wanted to use graphics with the HDMI card then I couldn't get going. And most distros want graphics. Don't confuse this with GUI options once you have a distro installed: all distros will allow a runtime non-GUI interface. I needed one at the INSTALL stage!

So, a server only distro might give that. I tried copying servers to a USB stick using unetbootin which previously has worked great. But I tried Ubuntu server and Fedora server and bizarrely neither of them worked: they kept failing to find necessary pkg files from the download servers. Eventually I got Ubuntu server to install - I guess the crappy Australian internet caused timeouts previously.

Booting off a USB stick wasn't fun. You have to turn off UEFI security in the BIOS boot menu (keep bashing the Del key on bootup to get to it). Even then, in the Boot Selection menu it only showed the USB stick as a UEFI boot, and that wouldn't boot. But in the Save and Exit menu it does show as both UEFI and non-UEFI boot. Choose the non-UEFI option.

For partitioning the hard disk, the default do-it-all-for-you only gives 8Gb for the root partition. That includes /var and /tmp so is ridiculously small. I prefer to set the disk partitions myself, giving 30Gb to root.

Then you can install the server - almost. Eventually you get to the Install Grub to a Disk. If you try it, it will fail trying to write to your USB stick on /dev/sda instead of your hard disk /dev/sdb :-(. If you don't try it, the grub packages won't be installed which will cause problems later. Either way, you have to end up selecting Don't install a boot loader.

Without a boot loader, the new server won't boot of course! Instead, using the USB again you need to get into Rescue mode. That sets keyboards and locations, downloads a base system, etc. Eventually you will get asked to drop into a shell prompt. Choose one for your hard disk's root partition. If you tried and failed to install grub to your boot sector then at least the grub package will be there. Otherwise you have to download and install the grub package - see next para.

apt-get is what you use to download packages. It requires networking to be okay. In rescue mode the resolve file /etc/resolv.conf is empty. It links to a non-existent file, so remove it first. Then you can edit it to add
(Google's nameserver) or similar. Then you can run
    apt-get install grub

Once the grub package is there, install it by
   grub-install /dev/sdb
(assuming your target hard disk is currently mounted as /dev/sdb).

So now I have a server system installed. To see if X worked, I ran
   sudo apt-get install xinit
and yes, it did. You can start X by
and it will run a single xterm. I then installed Tom's Window Manager twm. It's really basic but that's okay. I can run that from within my xterm to give me some control. i had to edit my .xinitrc to include
   xterm &
   twm    # synchronous!
Note that the display is still broken, but doing something really simple like this works (just).

So I got more ambitious and ran
   sudo apt-get install gnome-shell
That took over the login process and trashed my screen again, just like the install process. So there is my problem showing up.

By ctl-alt-F4 I can get into a terminal screen and check things out. I can run basic X, and it looks odd but something works. I installed Firefox but when I ran it, just a mess again - too complex for the problem case.

Maybe an up-to-date kernel. I downloaded kernel sources for 4.0.2 to another machine (no working browser on this one!) and copied it across. Built and installed it
   make install
   make modules_install
and it wouldn't boot as it couldn't find my hard disk. Also needed
   update-initramfs -u
So it booted, but the problem with the display didn't go away. Kernel 4.0.2 wasn't the answer. Was it the monitor? No, worked okay with another computer (well, sort of okay - the mouse left tracks across the screen, but I've seen that problem elsewhere with the HDMI driver. Kernel 4.0.2 was not the solution.

With a working command-line Linux at least I can now find out things about the Gigabyte. The cpu is an Intel i7-5500U @ 2.4 Ghz (but I knew that already from the specs). The framebuffer is an inteldrmfb. The graphics driver is the Intel i915.

The site
seems to be all about Intel graphics drivers. From there I found the Graphics Installer 1.0.8 for Ubuntu* 14.10, 64-bit
The fun starts here again. It requires Ubuntu 14.10. The defaults on the Ubuntu site are 14.04 and 15.04 so you need Google to find the server 14.10. Then it installs just as described above. The graphics installer has to run under X and apart from a few glitchy effects is navigable. But once it gets going, lots of flashing lights, stray bolts of lightning, etc from the graphics card. I switched to another virtual terminal until it finished. But it made no difference - no usable X. Not a solution.

Time to look for bug reports. I found the bug "Graphics unstable on Ubuntu 14.04 and 14.10 using Intel HD Graphics 5500" at
Fix #36 starts the X server in UXA mode instead of the preferred SNA mode (no, I don't know what they are)

    try to create the following folder:
    sudo mkdir /etc/X11/xorg.conf.d/

    Then create inside the new folder a file named for example "20-intel.conf" with the following content:
      Section "Device"
         Identifier "Card0"
         Driver "Intel"
         Option "AccelMethod" "uxa"

    Then reboot and voila."

This works! Most of the time.  Fix #100 didn't work on Ubuntu 14.10 (unresolved packages) although reports were that it worked for 14.04. But the moderator for that bug said that my bug wasn't his bug and I should log a new one.

In the meantime I had logged bug 90401 at Comment #5 pointed me to the development site for the xf86 intel video driver

   Please test the Xorg ddx driver from [1] and report back.


I downloaded 2.99.917commit baec802b21... and so far that one is okay. To build it required installing packages autoconf, autogen, autoreconf, xutils-dev xorg-x11-server-devel, libtool, pkg-config. Then run
    make install
in the xf86-video-intel directory

This removes /usr/lib/xorg/modules.drivers/ and installs /usr/local/lib/xorg/modules.drivers/ So far I can run Big Buck Bunny, the test suite glmark2 (test result only scores 119) (I got info about this test from Benchmark graphics card (GPU) performance on Linux with glmark by Silver Moon), browsers with YouTube movies etc.

So finally X is working, but I only have the server install. Get the GUI desktop by
  sudo apt-get update
  sudo apt-get install ubuntu-desktop

This  gives the Unity desktop. I'm not a fan of Unity, so I usually install old-style gnome by
  sudo apt-get install gnome-session-fallback
and Compiz (for wobbly windows) by
  sudo apt-get install compiz

1) install Linux using a server package with a command-line install. 
2) Get the latest source version of xf86-video-intel, build and install it
3) X should now work if you want to test it by downloading e.g. xinit and twm
4) Install the desktop package ubuntu-desktop


Monday, 29 December 2014

Brandis caught out by metadata

George Brandis, the Attorney General for Australia is proposing a compulsory metadata retention scheme for Australian ISPs. He showed on a TV interview a few months ago that he basically had no idea what metadata was all about, mumbling about addresses on (snail mail) envelopes. Well, this week it should have been brought home to him what the fuss is all about.

Brandis hosted a dinner party in London on April 4 for "a group of senior British arts representatives". The bill was £627, with £228 in alcohol charges alone. The Age newspaper reported this as "George Brandis' 'obscene' $1100 dinner funded by taxpayers".

The food and wine were the "data" in this transaction. The topics of conversation could probably be called data too.  The cost, and the people involved would be the metadata. We don't know what was discussed, but we do know that the metadata itself has left a big stain on Brandis' character and judgement. So George, metadata counts, and your proposed legislation needs to be very careful about what is collected and who can use it.

Wednesday, 17 April 2013

Behringer MIX800 ultra compact Karaoke machine

My search for Karaoke on my laptop led me to writing to a book still in alpha on Linux sound programming. But I kept returning to the original topic, and my question this time was on how to support two microphones. I also wanted to introduce effects like reverb because it makes the voice sound richer. I suppose that means two sound cards unless I can find one with two microphone inputs. Basically, to do it in software I need to duplicate a mixer preferably with FX for reverb.

Real mixers aren't usually cheap. The ones in Chinese DVD players are though, as a complete player with two microphone inputs and reverb effects is often less than $100. But I had thrown out my old players :-(.

Then I came across the Behringer MIX800 ultra compact Karaoke machine. You can get it from Amazon for US$64. I paid A$109 from an Australian distributor Store DJ. It's good: two microphone inputs with reverb/echo. One line input from your CD/Computer with voice cancellation (which works sort of). Play the karaoke files on your computer using kmid or my Java programs, feed the output to the MIX800, plug in your microphones and send the mixed output to an amp. Easy! No need to mess around with mixing by PulseAudio or other s/w. I'll get the s/w working eventually as I want it, but for now this is a very good and easy solution.

Wednesday, 30 May 2012

Found low latency for Karaoke with PulseAudio

As a followup to the last post: I can now play Midi files and sing along with no noticeable latency using PulseAudio. To direct the (default) microphone to the (default) speaker load the module_loopback (thanks to rusty0101):

    pactl load-module module-loopback latency_msec=1

Everything you speak/sing/holler will then be played on the speaker.

For Midi file playback I discovered FluidSynth. The following program will play a Midi file:

// See

// Run by ./PlayFile /usr/share/soundfonts/FluidR3_GM.sf2 ../54150.mid

int main(int argc, char** argv)
    int i;
    fluid_settings_t* settings;
    fluid_synth_t* synth;
    fluid_player_t* player;
    fluid_audio_driver_t* adriver;
    settings = new_fluid_settings();
    synth = new_fluid_synth(settings);
    player = new_fluid_player(synth);

    fluid_settings_setstr(settings, "audio.driver", "pulseaudio");
    // Use paman to find output device's name
    fluid_settings_setstr(settings, "audio.pulseaudio.device",

    adriver = new_fluid_audio_driver(settings, synth);
    /* process command line arguments */
    for (i = 1; i < argc; i++) {
        if (fluid_is_soundfont(argv[i])) {
           fluid_synth_sfload(synth, argv[1], 1);
        if (fluid_is_midifile(argv[i])) {
            fluid_player_add(player, argv[i]);
    /* play the midi files, if any */
    /* wait for playback termination */
    /* cleanup */
    return 0;

And whadda-you-know? It all works fine.

There's just the matter of hooking up a GUI, and a few thousand lines of code. But at least I'm starting from a good base, and I now realise the Java Sound framework can't give me that, sad to say.

Tuesday, 29 May 2012

In search of (low) latency

This is a followup to my investigations into playing my Songken DVD DKD files on my laptop. In an earlier blog I described how to decode the DKD files into Midi or Midi+WMA files. The intent was then to build a Midi player that would also show the notes of the melody and also the notes the singer was singing.

Well, I did all that. Java Sound has a Midi player. Java Sound has a Sampled API to handle sounds from the microphone to the loudspeaker. Java has a GUI for showing stuff. TarsosDSP by Joren Six has implemented a number of pitch detection algorithms such as YIN and they can be pulled in to give an estimate of the pitch sung. Java can convert characters from language encodings such as GB2312 to Unicode and display them so I can see Chinese and other characters.  So it's all there....

... but latency still kills it. The Midi player introduces latency somehow into the sampled sounds, but even if you work around it - even if you just do sampled data alone - then there is still that little delay. Here are my Java source files. Maybe I will write up an explanation of what I was doing with them later. I'm going to stop work on them right now till I get the latency sorted out.

The standard audio system for (consumer) sound on Linux is Pulse Audio. But as Lennart Poettering explained at the Linux Audio Conference 2010, pro audio has different aims to consumer audio, and this project is closer to pro audio than consumer audio (although to think of Karaoke singers as pros is stretching it a bit :-). In consumer audio, latencies of upto 2 seconds may be permissible, while pro audio sets an upper limit of 20 milli-seconds.

Java Sound is estimated to have a 50msec delay: "These measurements suggest that the latency introduced by buffers in the "Java Sound Audio Engine" is about 50 ms, independant of the sample rate." Now that's on old equipment, but it means there is an uphill struggle.

The sound quality of the builtin soundcard HDA Intel PCH (STAC92xx) on my Dell laptop is appalling. That has to be overcome too. This laptop doesn't have a microphone input, so I started looking at USB sound cards. My first attempt was with a AnPu Portable USB 3D Virtual 5.1 Audio Sound Card Adapter Blue  from Dino Direct. Dino was good: delivery post-free within 2 weeks. But the card was cheap (A$4) and broke when I inadvertently yanked it out of the USB slot.

My second attempt was with Swamp Industries for an XLR to USB Adapter. That was about A$20 but I got it with a microphone as well. The service was good again. Well, the card's okay for input, but still has to go out through the onboard soundcard.

The third attempt was with a Sound Blaster X-Fi Surround 5.1 Pro at A$70. It's a USB 1.1 device (Linux still has issues with USB 2 devices, apparently).  Pulse Audio only recognises it as an input device, not as an output device, so it didn't seem to improve things.

Pulse Audio is an audio layer above Alsa (OSS was used previously to Alsa). Alsa could see the device fine:

$arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: STAC92xx Analog [STAC92xx Analog]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 2: Pro [SB X-Fi Surround 5.1 Pro], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0


$aplay -l
card 2: Pro [SB X-Fi Surround 5.1 Pro], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: Pro [SB X-Fi Surround 5.1 Pro], device 1: USB Audio [USB Audio #1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Now about this time I went off on what turned out to be a wild goose chase (at least so far) by looking at Jack: "JACK is [a] system for handling real-time, low latency audio (and MIDI)". Jack currently also uses Alsa. Now that looks good - but Java Sound and Jack don't play together.

Java Sound has a couple of weird bits where "obviously equivalent" things aren't. I hit this first with volume control in playing a Midi file: you can't set the volume on the default device but you can if you iterate through the devices and select the default one. Then you can set the volume on it. Huh? Thanks to Greg Donahue for solving that one. You hit similar problems trying to find the sound cards and you end up either with
  • Java Sound not playing to your default card; or
  • When you explicitly select the default card then Java Sound throws an exception saying that its PulseAudio drivers can't find it.
So after all that, where are we?
  • Java Sound has latency problems
  • The inbuilt soundcard is crap
  • Pulse Audio can't properly find the USB soundcard
  • Java Sound uses Pulse Audio
  • Pulse Audio has latency issues
  • Jack is ignored by Java Sound
  • Alsa and Jack can find the USB soundcards
Is it possible to have latency-free sound on Linux? Well, Jack claims to be latency-free, but then it has to go through the Alsa layer. Can the Alsa layer be latency-free? Not completely, but I finally figured out the following test:

    arecord  -f dat -B 4  -D hw:0| aplay -B 4 -D hw:2 -f dat -

i.e record at DAT standard (16 bits, 48k samples) from the builtin mike (hw:0) played on the USB soundcard (hw:2), with 4msec buffer time. And hey! It works! No latency that my poor ear can hear. This simple pipeline isn't perfect: any overrun introduces latency into the pipeline, but that can be handled in code by dropping samples. The sample size can be increased and it still sounds okay - 4ms was the lowest I could take it.

  • the top-down approach through Java works but has latency issues
  • the bottom-up approach through Alsa handles latency
I just need to combine the two...