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8 décembre 2010 3 08 /12 /décembre /2010 16:27

This serie of 4 articles will cover in deep sound in a PC.

Part One : The basics and theory of sound

Part Two : Implementation of the Sound Processing at the Hardware level

Part Three : The various standards in Sound ( Cables, Standards, Hi Definition )

Part Four : Various topics and issues about PC Sound ( EAX, HDCP, PAP, Software issues )

Part Two : Implementation of the Sound Processing at the Hardware level

The different hardware sound architectures :

Sound is implemented at a hardware level using different hardware architectures : codec, soundcard, hdmi audio bridging, hdmi with discrete audio codec.

1. Audio using a codec

The codec implementation is by far the cheapest and most widespread implementation of audio in a PC these days. Codec implementation has reached a high enough quality to be fully satisfying to most users.

Here is the basic design ( click to enlarge ) :


Chipset Codec


The Audio Controller, located in thhe southbridge, performs most of the tasks : mixing channels, setting levels, special effects. It should be notted that the Audio Controller is just a controller. The actual computing is done by the CPU.

The Audio Codec is a separate chip, located on the motherboard. These days it is merely a ADC / DAC converter, not even mixing channels anymore, the mixing duty being done by the Audio Controller. This Codec chip is also named an AUDIO PHY.

Let's look at some detailed technical diagrams now. Here is an Intel southbridge Audio Codec implementation ( click to enlarge ) :


Notice the two Serial Datas links between the southbridge and the codec, and the digital and analog lines from the codec to the back panel IOs.



Let's look at the implementation on an AMD 785G chipset board ( for an example : ASUS ASUS M4A785TD-V EVO. 785G Northbridge, SB710 Southbridge, VIA VT1708S Audio Codec ). This is a pretty good multimedia / HTPC motherboard,  so we'll look at its specs all along this ' Travelling with sound ' serie ( click to enlarge ) .



( source : AMD official documentation )


Here is the internal diagram of a part of an Intel Southbridge. Notice the Intel High Definition Audio block in the diagram ( click to enlarge ) :



( source : Hardware secrets )



and last, here are the internal diagrams of the AD1888 and AD1988 A/B Audio Codecs ( click to enlarge ).

AD1888 :



the AD1988 A/B ( click to enlarge ) :


AD1988A 1988B






( To Be Continued ... )


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1 décembre 2010 3 01 /12 /décembre /2010 12:59

A fast and lean PC

A good OS installation requires only a few key steps that will ensure
the best efficiency and speed. Let's see these steps


1. drivers check

Unless you use the CD-ROM that comes with your brand new motherboard,
you may want to do a fast format and install, test the drivers installation,
to be sure of your drivers choice. PC manufactures' sites are sometimes
very unclear about drivers choice, and a good OS install requires a rule :
a perfect drivers install. Installation is not the time for drivers troubleshoot,
if you want the best installation

2. Partitionning scheme

A good partitionning scheme ensures the best reliability and performances.
( See the page post : Neat Partitionning )

Use full format for the final installation ( no fast format )




3. Proceed in dure ways and order :

     a) Partitions + OS install

     b) Services Packs install

     c) Drivers install ( reboot after each driver installation )

     d) Softwares install



4. Softwares

The rule is to keep it light and essential, to really have a fast, stable and neat PC.
So only install the mimimum ( and really needed ) motherboard softwares,
use lightweight softwares for common needed tasks ( pdf reader, codec packs, ... ).

The fewer and the lighter the softwares are, the faster and the more efficient your PC will be



5. Let it breath

During installation, after each reboot, wait a few minutes, so to allow the PC to finish its
complete boot process.

When installation is complete, disable Windows updates, reboot, install Antivirus software,
connect to Network ( internet ), make Antivirus database update, reboot, enable Windows Updates,
.... and let the PC rest for a time, performing its updates all by itself.

Only connect the ethernet plug at the last step, and then go for your Antivirus software immediately
( If you have it on CD it's the better : first install it, then plug in the ethernet )

I prefer to disable Windows Updates, and only re-enable it as the last final step, when all is in place,
secured, and rebooted, so it won't mess with important steps ( Service packs installation, .. )




Conclusion :

A good OS installation requires many tips, skills and care to really bring the best efficiency,
reliability and speed. Even security aspects are involved. It's really a crafting skill, that is worth
time and patience, to bring the best of our PCs.

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1 décembre 2010 3 01 /12 /décembre /2010 12:56


The second part of the virtualization will show a step by step

OS virtualization, using a light OS


It will underline many little tips, that can be troublesome for beginners


The choosen OS is Windows 98 SE, because installing a heavier OS

may take a somewhat long time. A light OS is a good choice for a first try.







I. installing Windows Virtual Server 2005


launch setup32.exe

from the start menu, go to Microsoft Virtual Server. Two icons are really usefull :

Virtual Server Administration Website

Virtual Machine Remote Control Client


You may want to copy the two links to your Desktop, for quick and easy access.

Virtual Server Administration Website is where you control your Virtual Server 2005 : making settings and administration.

Virtual Machine Remote Control Client is where you open a window to one of your virtual OS, allowing to actually use it.




II. Installing a Windows 98 SE virtual OS


Creating your virtual machine

As a first funny step, we're gonna install a light virtual OS. I did choose Windows 98 SE, but any light OS will do fine ( DOS, Windows 95, Windows 98, Windows 98 SE, Windows ME )


1. I like to use separate folders for virtual machines, so I go to :

C:\Documents and Settings\All Users\Documents\Shared Virtual Machines

and creat a new folder named W98SE :

C:\Documents and Settings\All Users\Documents\Shared Virtual Machines\W98SE


2. Lauch the Virtual Server Administration Website

( tip : sometimes, Virtual Server Administration Website refuses to launch. Using an account with administrator rights seems necessary, using an account with password may sometimes resolve some loging / securit issues )



3. On the leftside menu, choose virtual disk ) Fixed size virtual hard disk


4. Choose your virtual hard disk settings :

location : none



Virtual hard disk file name: C:\Documents and Settings\All Users\Documents\Shared Virtual Machines\W98SE\HD1.vhd

Size: 5 GB ( your choice here !! )


5. click Creat button


6. now we're gonna install our virtual Windows 98 SE :

on the left side, choose : Virtual Machines ) Create


7. Choose your virtual machine settings :


Virtual machine name

Virtual machine name: C:\Documents and Settings\All Users\Documents\Shared Virtual Machines\W98SE\W98SE.vmc


Virtual machine memory (in MB): 64


Virtual hard disk :


Use an existing virtual hard disk :

location : none



Virtual hard disk file name: C:\Documents and Settings\All Users\Documents\Shared Virtual Machines\W98SE\HD1.vhd

Bus: IDE

Virtual network adapter

Connected to: not connected


8. click Create !!


Your virtual machine has been created ! Now we're going to launch it :



Launching your virtual machine


9. Minimize the Virtual Server Administration Website window


10. Lauch the Virtual Machine Remote Control Client


11. Type in the path window :




( a few explainations here :


pc1 is my ( real physical ) computer name. replace this by your computer name


5900 is Windows Virtual Server default port


W98SE is your virtual machine name )


12. click the Connect button !!


Using your virtual machine


A few notes here about using your virtual machine :

You have to click with your mouse on the virtual machine screen to ' enter in it '. If there is a simple dot on the screen and the mouse cursor is not moving, left click on the virtual machine screen !!


There is a special key : it's the Host key. it's used to perform some special task.

by default, the host key is the ALT key at the right of the space bar. Here is what you can do with it :

Host key + ENTER = Toggle full screen

Host key + DELETE = CTRL + ALT + SUPR

Host key ( hold a few seconds ) = to get the mouse cursor out of the virtual machine


There is a menu at the top of the virtual machine window ( when it's not in full screen mode ).

this menu ( Remote Control ) allows you to :

use special keys ( like screen capture )

(re-)connect to server : by default, if you let your virtual machine iddle for too long ( 15 minutes ), it will disconnect

from the server ( althrough still running and well ) : use the ' connect to server ' menu choice to reconnect your virtual machine.


( Tip : some users may want to change the Host key : in this menu, there is a set Host key option. For exemple, I changed the Host key from (Right) ALT to (Right) CTRL, because I need the (Right) ALT key to be usable in DOS mode so that I can type in the ' \ ' character in files paths )


How do you turn off your virtual machine when in ' POST / DOS ' mode ? Go to the

Virtual Server Administration Website


either go to : Virtual Machines ) Configure ) W98SE


: navigation ) Master Status

there is a mini-screen caption of your virtual machine. At the right of it, there is written : W98SE

hover your mouse over the WIN98SE word : a menu will appear. You can there ' Turn Off ' the virtual machine


( to re-launch your virtual machine, go to the ' Launching your Virtual Machine ' step )


some last notes here : while in POST / DOS mode, the CPU keeps running 100% . Be carefull with your CPU over-heating ! ( When your virual machine enters GUI mode ( like windows 98 desktop ), the CPU returns to normal use )


important : toggling between ( Physical ) PC Desktop and Virtual PC Desktop seems to mess with the num-locks status light. This can be very troublesome when trying to type password when logging-on an account when using a virtual machine, because you can't see what you're really typing. If your password is rejected, toggle the key-pad num lock, whatever the num-lock light is indicating.


( Tip : Your virtual machine has a ... virtual BIOS setup screen, for boot order, etc ... Use the escape key to enter it,

at the beginning of the boot process. Important : type the escape key very fast, right from the start of the boot process or

you'll miss the opportunity window. you only have 1 or 2 seconds )


Installing Windows 98 SE virtual machine



well, nothing really difficult here :


just launch your virtual machine, put in the installation CD of Windows 98 SE, reboot the virtual machine, and do a regular installation.


( tip : some users may want to boot from a DOS CD-ROM, do FDISK for partitionning, do FORMAT C: for formatting, do MD WIN98 + COPY D:\WIN98\*.* C:\WIN98 for install files copying, etc ...


tip 2 : no floppy drive is present by default in your WIN98SE virtual machine. Go to the

Virtual Server Administration Website : Virtual Machines ) Configure ) W98SE )

Floppy Drive ) Physical Floppy Drive ) OK )



You may like to save a copy of your new-virtual machine for easy backup / recovery :


just make a copy of the W98SE.vmc and HD1.vhd files to another folder !!


( tip : using a freeware tool like 7zip may be very usefull. Using default compression settings, I made a compressed copy of the whole W98SE folder ( Folder + W98SE.vmc and HD1.vhd inside ) : my 5 GB fresh installed Windows 98 SE Virtual Machine got compressed to a amazingly little 176 MO !! That's very usefull for transport or CD Burning of the Backup of your virtual machine




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1 décembre 2010 3 01 /12 /décembre /2010 12:10

Travelling with Sound

This is a serie of 4 articles that will cover in deep sound in a PC.

Part One : The basics and theory of sound

Part Two : Actual implementation of the Sound Processing at a Hardware level

Part Three : The various standards in Sound ( Cables, Standards, Hi Definition )

Part Four : Various topics and issues about PC Sound ( EAX, HDCP, PAP, Software issues )

Part One : The basics and theory of Sound

The signal path :

The path the sound uses through the process can be thought off in three parts :

1. Source input ( and eventually Analogic to Digital Conversion )

Soundwawes have to be of numeric form to exist in a PC world. There is two cases then :

. Either the source is numeric ( a CD for an exemple ), then the PC will directly process this
numeric content

. Either the source is analogic ( a microphone or an analog line in plugged into the PC), then
the PC will have to digitalize it ( to make it into a numeric format ) : this is named ADC ( Analog to Digital Conversion ). Then, the PC will process this digital content.

2. Signal processing

The numeric signal will be processed in different ways by the PC ( decodig logics, formats conversion, mixing, special effects ). Exemples of decoding logics are Dolby DIgital 5.1 or EAX.

3. Source output and Digital to Analogic conversion
After this numeric content has been travelling and processed in the PC, it will have to be made into an analog format, before being amplified and sent to a speaker. This is named DAC ( Digital to Analogic conversion ). There are two cases here too :

. Either the PC makes the Digital to Analogic Conversion ( DAC ) itself, and the analogic signal is sent out to a sound amplifier, using an analog cable plugged into the PC. This will use the analog outputs of the PC

. Either the PC sends the numeric signal directly out of the PC to an amplifier that has numeric inputs using a numeric cable plugged into the PC. The amplifier will make the Digital to Analogic Conversion ( DAC ). This will use the numeric outputs of the PC : Coaxial SP/DIF, Optical SP/DIF, HDMI.

This final Analogic signal is then amplified, and sent to the speakers. This is the whole signal path.

Sound caracteristics :

Digital sound has a number of characteristics that are important to understand clearly.
They are bit depth, sampling rate, and encoding.

Analogic sound, as well as ADC and DAC conversion, have characteristics that are important to understand too : SNR, Frequency response, Dynamic range, THD, signal level.

1. Digital Sound characteristics

This is the picture of a basic digital sound :


( image from wikipedia )



The red line is the digital signal. The grey wave is the Analogic signal it corresponds to.

The more vertical subdivisions there are on the vertical axis, the more accurate the digital signal will stay to the Analogic signal : this is Bit Depth

The more horizontal subdivisions there are on the horizontal axis, the more accurate the digital signal will stay to the Analogic signal : this is the Sampling Rate.

The higher these two values, the more precise and accurate the sound will be.

For an example, a CD is 16 bits ( bit depth ) and 44,1 kHz ( sampling rate ) sound.

An analogy to Video signal quality would be bit depth = number of available different colors and sampling rate = number of FPS ( Frames per Second, ie Images per Second ).

A third caracteristic of a digital signal is its encoding. While the above exemple is a simple digital signal ( that is named PCM or LPCM ), several digital signals can be compressed and/or coded into a specific bundle : MP3 ( compression ), Dolby Digital ( Multichannel +
compression, etc ... )

Bit Depht and Sampling Rate are important in ADC and DAC conversion too, as they decide the conversion quality.



( image from wikipedia )


2. Analogic Sound characteristics

The Analogic parts of the signal path have some very important caracteristics too. They are :

SNR : Signal to Noise Ratio. This is the ratio between the actual sound and the background sound ( white noise, ... ) that is added to the signal by a particular device. To hear this noise, start playing a CD, pause it, and turn the volum high : the hissing sound you hear is this added noise. The SNR is expressed in decibels. The higher the number in dB ( decibels ), the less noise will be added to the original sound.

Sound devices always create some noise : Amplifier, Sound Card, ...

Frequency response : The width of the frequency band a device can reproduce. Human beings have an average hearing range from 20 Hz to 20 KHz. The device should be able to reproduce as much as this range, and with the lowest volume modifications from the original signal depending on frequency. The Frequency response is expressed in Hz ( band width ) and Db ( volume accuracy ).

A close to ideal Frequency response would be 10Hz-30KHz ( band width ) 0 dB ( volume accuracy ). The highest the first number, and the lowest the second, the more accurate the sound will be.

Dynamic range : Dynamic Range is the ration between the lowest volume and the highest volume a device can process. It is expressed in dB. The higher the value, the better. An analog cassette has a Dynamic Range of 60 dB, a CD 100 dB.

THD : Total Harmonic Distortion, expressed as a percentage. It is the level of harmonics added to the original signal. The lower is the better.

Signal level : Analog line signal has to have a good voltage value, so that the signal is carried strong and clean. A good signal level helps avoid noise to be added during the signal travel, either trhough the device, or from device to device. It is expressed in V (Volts ) and has to be high.

Other values: There are some others numeric values sometimes quoted :

Stereo crosstalk : noise and sound induced between channels

IMD : ( Inter Modulation Distortion : Distortion not harmonically related, expressed as a percentage.

THD+N : Total Harmonic Distortion + Noise, expressed as a percentage. It is the level of harmonics+noise added to the original signal. The lower is the better

IMD+N : IMD + Noise. Distortion not harmonically related + noise added to the original signal. Expressed as a percentage,the lower is the better

These last four values have to stay has low as possible.

Amplifiers also state output power, that is the highest sustainable non-clipping non-distorded sound an amplifier can send to the speakers. This value is expressed in Watts. The higher the better.

Conclusion :

The sound path is a complexe and long travel through digital and analogic devices. It needs a clear understanding of both this path and of the numerics used to evaluate it.

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4 octobre 2010 1 04 /10 /octobre /2010 17:16




GPU Monitoring and performance evaluation is not a so simple task. While PC / OS monitoring is quite simple

( using the task manager to check memoty usage, pagefile usage, CPU load ), there is no native tool in Windows

for GPU. I'll explain the basic steps for GPU Monitoring / Troubleshooting




1. GPU-Z

The freeware GPU-Z is the basic tool. Using the second tab ( Sensors ), you can check the instant values,

as well as the min and max values for each parameter. Click the pull-down menu next to each value, to toggle

instant / min / max values. This way, after a couple of hours of GPU use ( ie playing some graphic intensive game ),

you can check the max loads, the current temp, the max temp, as well as checking the temp decrease while back in

Windows Desktop.

Remember to click the two checkboxes : ' log to file ' and ' Continue refreshing this screen while GPU-Z is in the background '







2. Graphs tracing using GPU-Z


GPU-Z will save a GPU-Z Sensor Log.txt on your desktop. You can use this file to make graphs.

I'll tip on how to do this, using Open Office Calc.


1. Activate all logging options in GPU-Z : ' log to file ' and ' Continue refreshing this screen while GPU-Z is in the background '


2. Keep GPU-Z open on the Desktop, launch the game, and play a couple of hours


3. Shutdown the game, and wait 30 minutes


4. Shutdown GPU-Z


5. Open GPU-Z Sensor Log.txt in Open Office Calc using the file type option in the open dialog box :

file type : CSV text ( *.csv *.txt, *.xls )


6. add the ' comma ' checkbox in the text import dialog box


7. In the Datasheet, select all + order by time ( so to eliminate the blank lines )


8. In the Datasheet, select all + replace . ( dot ) into , ( comma ) ( for numbers proper handling )


9 go on the bottom of the page, grab the last line ( collumn tags ) and insert it at the top ( first line )

( so you have proper collumns tags )


10. Select all + insert graph


          graph type : lines

          check first line and first collumn as tags


11. Move and resize your graphic


12. Save the datasheet, and make screen captures using pan and zoom different options


A few captures sheet of Anno 1404 over a GeForce 7800 GT :


Whole game session ( click to enlarge ) :





 A zoom over the session beginning ( check temp rise ) ( click to enlarge ) :






A zoom over the end of session ( check temp decrease ) ( click to enlarge ) :





These three graphs show that :


 . GPU memory gets fully loaded


. GPU is working at a 100 % load through the whole game session


. GPU temperature is way high



Well, it's no big surprise Anno 1404 is a little too much for a 7800GT, but now

you can check where and how it actually have some difficulties.


Interesting too, if you notice, the temp spikes just fit the CPU use spike and the memory

controller spikes.


Tip : A GPU-Z Sensor Log.txt of a 2 hours test has many datas, so be patient for Open Office time of compute

and results display. Too, tou'll have to make tradoffs, since the whole session view shows the whole session,

but lacks dots resolution. On the opposite, close-ups zooms shows a very detailled graph, but lacks the

' whole picture ' interest. Data viewing softwares can be of some help here ( GNUPlot, ... )



Conclusion :


Having a few tools to monitor and graph GPU activity is very funny, very interesting, and ways improve your

knowledge of GPU performance. It's allways worth trying it !!!



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13 décembre 2008 6 13 /12 /décembre /2008 06:00

Microsoft Virtualisation is an awsome tool to tryout new Operating Systems, use an alternate OS without dual-booting or even having to change the Formating structure of the Hard Disk Drive, for security, or for learning purposes.

I'll explain a basic tutorial on running Windows Server 2003 on a Windows XP Pro PC.

Be sure to download from Microsoft the files version that matches your config ( depending on you're running XP SP2 or XP SP3, 32 bit OS or 64 bit OS, etc ... )

First, you'll have to download the Virtualisation software :

Virtual Server 2005 R2 SP1 ( Free ) from Microsoft website. ( 40 MB )

Second, you'll have to download the OS image :


Windows Server 2003 R2 SP2 ( Free, 30 days limited ) from Microsoft website.
Windows names these OS images VHDs ( Virtual Hard Drive ). The download is huge ( 2 GB ), so be patient, and be sure your internet connection is stable and safe.

You'll need Windows XP Pro : XP Home can't run Virtual Server 2005.

You'll need a powerfull enough CPU and enough memory to handle the virtual server extra load. I'm using right now an Athlon XP 1800+ with 768 Mo of SDRAM, and it feels like it's the minimum.

Be sure to download from Microsoft the files version that matches your config ( depending on you're running XP SP2 or XP SP3, 32 bit OS or 64 bit OS, etc ... )

One last step to prepare the installation : Add the IIS World Wide Web Service component to your OS
( Control Panel ) Add or remove programs ) Add or remove Windows Components ) Internet Services ( IIS ) ) Details ) World Wide Web Service                       )

All is ready for installation now.

( the following of this tutorial will be added very soon ^^ )



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13 décembre 2008 6 13 /12 /décembre /2008 05:45
Where is the History icon in IE7 ?

Althought IE7 offers many nice new features, like Tab navigation, one strange aspect is the diseapearing of the History icon . Actually, it is still here : It's the little yellow star at the top left of the page.
This little yellow star is named ' Favorites center ', which is confusing

Just click it ! : a panel opens. At the top of this panel, there are three icons : Favorites, RSS, History.
Click on ' History ' and you're done ! Now, each time you'll click the little yellow star, you'll have direct access to your History log ( except if you toggle so more. I'll always open the last used of the three icons Favorites, RSS and History )

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