Operating System: What is it, and what you should know about it

[amirm]

You have heard the names: Windows, MacOS, iOS, Android, Linux. These are all examples of very popular operating systems. Being the most critical component of our computing devices and increasingly, consumer electronics, it is important to have an understanding of its functions and capabilities.

The operating system is specialized software that sits between your computer hardware and the applications that run on top of it. The motivation for creating it was to make it easier for software developers to write their programs. By isolating the programs from the hardware, programs could more readily be moved from one hardware platform to another. Think of how you can upgrade your computer to a faster one with totally new hardware yet able to install the same software it as the old. This is accomplished by the operating system providing an interface to the hardware capabilities that does not change.

Read the rest here: Fundamentals of Operating Systems

And ask your questions here . But do leave comments in the above article also if you are a facebook user .

 

[Jaguar]

I've recently moved on from Win 7 to Linux and will release a new machine based on a super-slim Linux version in late Dec. Our philosophy is a minimalist-approach, based on the CMP2 project. BTW, the CMP2 site is my most recommended source for DIYers who want to delve into building their own machine and the tutorial on the Genesis Loudspeaker website is also worthwhile.

Many servers out there try to be all things to all people, which is fine if you’re building a general-purpose multi-media server, but not when you’re talking about connecting it to a world-class audiophile system. In Windows, I can detect a change in audio quality just by turning off the Intel HD graphics driver and reducing the color depth to 8-bit; think about that if you’ve got $50k worth of gear hooked up to a server with HD graphics, network capability, iPad control, virus scanner, etc.

The last server, which I had in our reference system for a while, has a lightly tweaked Win 7 OS alongside a highly tweaked Win 7 audio OS. The normal boot section can connect to the Internet and is set up for Blu-ray and other video. Latency measurements in the audio boot section are less than half that of the regular section and the difference in sound quality is quite surprising, given that both OSs are booting on the same fan-less hardware.

As operating systems go for audio, a default installation in OSX (which is based on Unix) will beat a default installation in Windows (which is based on DOS) however, Windows is much more amenable to tweaking and you can disable substantial portions of it in the back end. A friend from my audio club and I compared the tweaked Windows/Foobar setup to his Mac Mini, with Pure Audio and Amarra and the Windows setup came out ahead with either player.

However, I believe Linux (which is based on Unix) presents by far the most elegant and efficient platform for audio. Unfortunately, the learning curve on Linux is quite high. When I started it took me 2 weeks to figure out how to install it and another 2 weeks to get the sound to work (this was after already knowing Windows like the back of my hand). Moving to a more compact and resource-efficient version of Linux presented a second learning curve. There are also potential hardware compatibility issues with Linux for certain sound cards or DAC with custom USB Drivers (we’ll offer the tweaked Windows audio OS as an additional option), but it’s not nearly as bad as you might think. Any DAC that doesn’t have custom drivers will work with Linux and many of those can still use the other drivers (ASIO4All works for my Wyred4Sound DAC, in Win 7, and sounds a little better than the custom driver.). My current audio OS in Linux uses approximately 20% of the memory resources as my Windows audio boot section and I still have a majority of the tweaking left to do (I think this might cut it by at least 60%).

BIOS optimization shouldn’t be overlooked either. A BIOS with default settings can have dramatically higher latency readings in the OS than with optimized settings. If you run a super-tweaked audio OS on the machine by itself you can go a little further in the BIOS in trimming the resources, but most people find it a little more convenient to have a 2nd OS to rip CDs on the same machine.

Anyway, there’s no shortage of DAC designers who will tell you that the server is irrelevant with their DAC or their async driver, etc. Pure BS in my opinion. On a highly-resolving system you will hear the hardware (motherboard, fans, drives, power supply, power cable), the OS (kernel, interfering processes and overhead, memory usage, drivers) and the player.

 

[fas42]

Anyway, there’s no shortage of DAC designers who will tell you that the server is irrelevant with their DAC or their async driver, etc. Pure BS in my opinion. On a highly-resolving system you will hear the hardware (motherboard, fans, drives, power supply, power cable), the OS (kernel, interfering processes and overhead, memory usage, drivers) and the player.

Good to see another person going down the fussy road ... :b:b

Frank

 

[Ronm1]

building a general-purpose multi-media server, but not when you’re talking about connecting it to a world-class audiophile system.

I somewhat smile when I see this term now used in describing server apps. General Purpose had a similar but diff feel when I got into the puter biz after my Navy hitch in 70'.

 

[Jaguar]

Hi Frank, I've seen some of your posts and I think you're not kidding; I'll bet you are up nights obsessing over the same stuff.

The claim that probably meets the most skepticism from audiophiles is that power in a server can affect your sound. The foremost expert on this, in my mind, is Greg Stewart, based on the amount of work he’s done on computer power supply and sound card mods (as in the post below). Linear PS for PC is not very practical, because there aren’t any commercially available options and you have to supply 3 different voltages (with a sound card). Regarding the power cable, if I only had one good one, the server is the last place I would use it. I believe the BIOS and OS are much more productive areas for gains and the quality of the clock on your DAC is going to trump everything. That said, the timing for audio bits is measured in pico seconds (billionth of a second) and with audio files there’s no fixing it once the timing is off. In other words…jitter induced by your power. 15ps is the figure I’ve seen quoted by Steve Nuggent, as the level of jitter that could probably not be detected by the human ear. And as soon as someone uses the term "bit-perfect" in your presence...run away like King Arthur and his men running from a deadly rabbit.

http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=48851

 

[fas42]

Linear PS for PC is not very practical, because there aren’t any commercially available options and you have to supply 3 different voltages (with a sound card)

Howdy, fork. Yep, I'm pretty obsessive, still trying to get a 100% handle on everything that matters!

Regarding the PS type, strange though it may sound, in one way I think it's not such a practical problem to eradicate interference due to its operation as a switch mode: if correct engineering is used in that area it should be fairly straightforward to knock over.

I believe the BIOS and OS are much more productive areas for gains and the quality of the clock on your DAC is going to trump everything.

I think the business of trying to get the CPU operation as "clean" as possible is not the most long term beneficial way of going about "fixing" the problems: as soon as there is the slightest change in the software it may mean that all the gains to date are now less effective. My way would be to leave the processor box to be as messy as it likes, and fix the problems from the outside of that box.

That said, the timing for audio bits is measured in pico seconds (billionth of a second) and with audio files there’s no fixing it once the timing is off. In other words…jitter induced by your power. 15ps is the figure I’ve seen quoted by Steve Nuggent, as the level of jitter that could probably not be detected by the human ear. And as soon as someone uses the term "bit-perfect" in your presence...run away like King Arthur and his men running from a deadly rabbit.

As I have said elsewhere a number of times, I don't believe jitter in of itself is anywhere as much a problem as some feel. And jitter can always be fixed up after the fact, it's a straightforward engineering task. No, what's more likely, in my experience, is that there is a lot of high frequency interference coming down the cable along with the data, and that has to be stomped on. This is not trivial to do, so unless proper engineering expertise has been applied to the situation this type of "dirt" will seep through to the analogue side and muck up the sound.

Cheers,
Frank

 

[Jaguar]

I don't have much direct experience with listening to PS mods in servers. Greg is the expert. I've done small things like powering fans and drives externally and with filters, which I believe to be beneficial and worthwhile.

I can't agree with you about tweaking the OS and the BIOS. Most changes, like using a new player software, don't result in stability problems. Changing OS from Windows to Linux resulted in some issues from my BIOS optimizations; I just reoptimized the BIOS with Linux and saved the settings (I could easily switch back and forth on boot up, if I want). I believe the tweaking to be indispensable. As I said earlier, I can boot into the modified OS and then into the stock OS on my machine and there's no question that the audio OS sounds better and the latency tool shows that it performs better. Files, hardware, BIOS and everything else is unchanged. As a matter of philosophy, I don't believe in leaving something unfixed, to be caught downstream, unless there's some drawback to fixing it; I'm going to use every tool I have to fix it upstream (OS Tweaks) as well as downstream (speaker binding post filters).

Electrical interference in the machine is the root cause of some jitter. In fact, this is probably the kind of jitter we're talking about for the most part. Jitter that's consistent can probably be handled pretty well with today's DAC/Reclocker devices. From what I've read, the whole issue of jitter is really voodoo science, even to technical experts and nobody has the money to buy machines that can accurately measure jitter. There's also plenty of debate over the proper way to measure it. Plenty of debate about jitter on this forum. Much of what I do, such as throttling the CPU voltage or launching a bat file at startup to give the player CPU priority, don't have any audible effect alone, but I believe that enough of these things put together make a difference.

 

[fas42]

I can't agree with you about tweaking the OS and the BIOS. Most changes, like using a new player software, don't result in stability problems. Changing OS from Windows to Linux resulted in some issues from my BIOS optimizations; I just reoptimized the BIOS with Linux and saved the settings (I could easily switch back and forth on boot up, if I want). I believe the tweaking to be indispensable. As I said earlier, I can boot into the modified OS and then into the stock OS on my machine and there's no question that the audio OS sounds better and the latency tool shows that it performs better. Files, hardware, BIOS and everything else is unchanged. As a matter of philosophy, I don't believe in leaving something unfixed, to be caught downstream, unless there's some drawback to fixing it; I'm going to use every tool I have to fix it upstream (OS Tweaks) as well as downstream (speaker binding post filters).

I'm not talking about stability issues, rather that a gain in sound quality may be somewhat nullified if, for example, there is an upgrade to the player software, which now drives the CPU into new patterns of processing.

Fair enough to have the philosophy of aiming to fix everything, this can do no harm, only good: it's just that I would aim to fix things first that I have total control of, the physical signal after it emerges from the server box. Bomb-proofing this means that other influences, totally unrelated to the server, will restricted in their ability to cause problems.

From what I've read, the whole issue of jitter is really voodoo science, even to technical experts and nobody has the money to buy machines that can accurately measure jitter. There's also plenty of debate over the proper way to measure it. Plenty of debate about jitter on this forum. Much of what I do, such as throttling the CPU voltage or launching a bat file at startup to give the player CPU priority, don't have any audible effect alone, but I believe that enough of these things put together make a difference.

I wouldn't call it voodoo stuff, people who have to deal with this on a daily basis have a good handle on it; it's just that the crossover into the audio world seems to bamboozle a lot of people. As regards measuring it, not a problem, you can buy chips which dejitter clocks to sub-psec accuracies: you can't sell these unless you can prove their competence, with measurements.

What I will heartily agree with you on, is that everything makes a difference: the better the system, the more this is true!

Frank