Why aren't computer clocks as accurate as cheap quartz watches?

D

How about offering some insight rather than just a big buzzer?

Depends on the version really, Win 3.1 and earlier didn't offer pre-emptive multitasking, when an application was minimized it generally ground to a halt. Win 9x was a big improvement over this but still mediocre. Win NT/2K/XP is better still, and are generally quite good OS's, but the multitasking is still rather poor compared to several other OS's on the market. Of course any OS is a compromise, what you gain in one area you often lose in another.

Poor calibration at the factory, and the fact that the clock time is often a blend of RTC time and various real or imaginary timers inside the OS.

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There's much more than that. There's NTP, which will keep your system clock accurate to within milliseconds without too much trouble. You can also get radio-controlled hardware clocks for installation inside the machine, as well as GPS clocks for even better accuracy. Radio-controlled clocks and NTP over broadband are grossly comparable, but GPS is more accurate still. All of these are far more accurate than the basic clock in the PC alone, which is often off by seconds per day.

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The truth is, I could care less about what you think about what I say. You are in no position to tell me what I should or what I should not do or have done. If you where a man worth listening to, you would simply post your opinion with no need to tell others how they should or should not have written there post. Truth is, you get off on taking jabs at other rather than simply posting what you think, (typical of a NG twit who cannot be aggressive in the real world for fear of getting bones crushed) Oh, and by the way, What you think it not, nessiccarily the only opinion that counts or matters. So, like I said before, f*ck you! And I'll post answers in what ever fashion I wish and I will be the judge whether what I post is relevant to the conversation. I don't need you to tell me that either.

Who the f*ck do you really think you are? Cause you aint shit to me....

And by the way, your little game of taking bits and pieces of previous threads is as annoying as the five second sound bite that removes the true context of the conversation and twists the words to suit your own purpose. It is quite transparent as we can all go back and read the thread as it was originally posted. Idiot.

Truth of the matter is that the program, "D4" is relevant to this conversation as somebody else may come along and read this thread who never knew the situation could be correct with a small transparent bit of software. That person may appreciate the fact that I brought that subject to the table. Oh, and By the way, the OP might as too. You see, the world doesn't revolve around you and what you think..

Oh, and here is my complete response to Rick Yeager

So what? I had offered an answer to that as well as offering a solution. Perhaps you didn't read that part of the thread.

Now, Had I said your pc's clock will run slow because magic trolls and ferries sneak in make adjustments to the master oscillator. That might warrant an attack. But the rest of this crap is just that, crap!

you see my mind is not one dimensional, I might take a question and expound on the answer to not only give a reason why this happen but also offer a way to correct it.

And by the way, my last comment was prefaced, "Just in case anybody is interested". Obviously you are not so the post was not intended for you. In other words, Bug Off, pedal on and get a life!

You took 8 word out 4 paragraphs... Who do you really think you are?

I'll ask you again to kindly f*ck off.......

If you want time that is perceptibly correct (that is, no perceptible difference between the PC clock time and a reliable standard reference when you watch or listen to both), you need to reset the clock of most PCs several times _per day_, as it may be off by as much as several seconds in a day.

There's also a registry entry that can be modified to make the system synchronize more often.

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Sixteen-bit versions of Windows never did preemptive multitasking. Thirty-two bit versions did and do, for 32-bit applications (but not for 16-bit applications). Windows NT does it for all applications, although a single MS-DOS virtual machine counts as one application (so multiple 16-bit apps running inside it are not preemptively tasked among themselves, for compatibility).

It would not grind to a halt if the current application relinquished control properly and frequently. However, all applications in the system had to be well behaved in this way, or things would stall.

It only did it for 32-bit applications, and overall Windows 9x was very poorly written.

Not true. Multitasking on all the NT-based versions of Windows is excellent. On those rare occasions when one application stalls another on an NT-based OS, it's not because of any defect in multitasking, it's because of interprocess signalling that stalls applications by (potentially poor) design. For example, the Windows Explorer is a potential source of multiple-application stalls, although the latest versions of Windows Explorer are far better behaved than the original (which was lifted from Windows 95, and was thus very poorly written).

Of course, systems such as UNIX have been successfully multitasking since the beginning, given that they were originally timesharing systems by design.

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No, windows NT does not pre-emptively multitask.

This is because it only multitasks, but it is not pre-emptive multitasking. The kernel does not have complete control of each application.

It is very good, but it is not pre-emptive. OS/2, for one, uses pre-emptive and it is so far ahead and superior to the way windows works, folks would not believe it. The difference between the two is beyond night and day.

The difference will prove to be in your definition. The original definition has been absconded with by microsoft in order to make it appear that their inferior implementation actually meets the requirements, so if it is really important that you 'win' that's okay with me.

Mark

Win 16 code on Windows 95 executes "cooperative multitasking". The application program must volunteer to pass CPU access to the next application. Furthermore Win16 code is non reentrant.

Windows 95 could only execute Win32 code using a flag called Win16Mutex so that Win32 code, designed for pre-emptive multitasking environments, would not crash in the 'mostly' Win16 environment of Windows 9x/ME.

To run Win16 applications in the preemptive multitasking environment of NT, those Win16 applications would execute under NTVDM. Therefore Win16 applications could execute in a pre-emptive multitasking environment called Windows NT.

To be a true multitasking system, all threads must be reentrant. This NT does. To be preemptive multitasking, the OS rather than the application programs must determine which code has CPU resources. This too is done by NT. Neither is done in Windows 9x. Some still confuse this difference between Windows 9x/ME and the Windows NT/2000/XP operating systems.

NT, however is not a superior real-time pre-emptive multitasking (MT) system. NT was not designed as an efficient real time OS because response to interrupts can take a millisecond. But this discussion is about preemptive MT. Windows 9x/ME is not pre-emptive multitasking. It is cooperative MT. A legacy of DOS and Win 3.1 upon which it was constructed. NT was built from scratch in the earliest 19990s to use Win32 code (code that is also reentrant) and to be preemptive multitasking. XP being only the latest version of the NT Operating System.

Some preemptive multitasking OSes take it to the next level

- real-time preemptive multitasking. NT can perform real time operations - just not fast enough - microsecond response - as some high performance systems require.

OS/2 did provide preemptive multitasking when Windows 95 could only do cooperative MT. However OS/2 has no useful graphical interface. Therefore OS/2 ended up in embedded applications such as ATMs - where the system must be more reliable - therefore system required a preemptive MT OS. Obviously Windows 9x/ME suffer from that reliability weakness. But NT is preemptive MT and has a graphical interface. NT was Microsoft's answer to OS/2 when IBM and Microsoft finally had a parting of the ways in early 1990s.

BTW, the early OS/2 that was first dem>> Sixteen-bit versions of Windows never did preemptive multitasking.

Yes, it does. I've seen the code.

It does preemptively multitask, and the kernel has complete control of all applications.

You're still applying the principles of 16-bit Windows and Windows 9x to the NT-based operating systems. The latter are completely different operating systems, though, rewritten from scratch, and they don't have anything in common with other versions of Windows except for the look and feel of the user interface.

It is both good and preemptive.

OS/2 is dead and gone, and although it was superior in design to the old versions of Windows, it was not superior to NT.

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No you haven't No one person has seen all those lines of code. If you want people to believe you are privy to the inner workings of the NT kernel, you will have to explain how you found the time to read and understand so much of it that you can make such a bogus statement in the first place.

Talk is cheap on usenet. No one is impressed. Hey, for all you know, I was on the development team.

Nope. Like I said, you do not have the proper defintion, or if it makes you feel better, we are not applying the same definition.

Everyone knows NT/XP/2000 is not windows 95. Don't treat your readers like they are dummies.

Nope. Sorry.

Hardly dead, and oh by the way, NT was built on early OS/2 code. NT and

2000 had plenty of OS/2 code in their kernel, and can even run text mode OS/2 apps. If you had seen the code...... you would know that.

I am not advocating it, I only pointed out that its multitasking was true, pre-emptive, and vastly superior to any MS product. Oh, BTW, the first versions of windows wouldn't even run a day without crashing and had more bugs than lines of code. So what does that have to do with anything?

Even worse, the

And when first released, windows was a total disaster. Again, so what? Stay in the present. At its peak in the late 90's, OS/2 was a cadillac to M$'s yugo. You can always argue app support, but technically, nothing holds a candle to OS/2. If MS was allowed to be crap for 10 years, and is now glorified, why do you think it matters that OS/2 had problems at first as well? The SIQ was the cause of just about any hang on any OS/2 system. When that was not an issue, NT could not stand up to OS/2 for stability. When Billy glued that dopey GUI onto NT, its reliability tanked.

There is a reason why OS/2 ran every ATM on the planet until the banks sold out to billy. If your ATM works, its OS/2.

OS/2 was not profitable for a lot of reasons, the largest of which came out in the MS trial, when we all learned that gates blackmailed IBM into killing it off. Again, totally irrelevant to the topic at hand.Profits do not equate to quality and features. I would take a BMW over a Ford any day, but Ford sells more product. Doesn't mean their cars are better, it just means they sell more of them. Again, so what?

According to some people's warped definition of preemptive multitasking, but NT's "idea" of it was not what preemptive really is, as demonstrated in OS/2 (not early releases, like you are whining about)

Wake up. NT WAS OS/2 as taken by gates when he split from M$ Everyone knows bill never invented anything, or wrote an OS from the ground up. He took NT from IBM as part of the parting of the ways, and found people to embellish it, except he took what you are whining about which is the versions that could not do preemptive multitasking. Shoot, he couldn't even pull the OS/2 code from the kernel until XP came around. Such a brilliant mind he has.....

Wow. Dumbest statement I ever read on usenet. Apparently, you never, ever saw OS/2 on a desktop. Most people will agree that the OS/2 Object Oriented interface is superior in every way to anything M$ has ever stolen. The OS/2 desktop is legendary. Can't believe you never saw it.......

Guess that pretty much blows any credibility you were hoping to show off around here.

No useful graphical interface. Yikes.... You really are clueless.

Uh, yes, I have.

I haven't read every line, but I've seen most of the cool stuff. It was a hobby of mine at one time.

You don't need to look at the code. Just write a program that runs in a tight loop, and run it. If you can still switch to other tasks in the system, you have preemptive multitasking. And on NT and its descendants, you can do exactly that.

No, you weren't.

I've spent part of my time writing operating systems for a living. I have the right definition.

But many of them don't seem to know much more than that, and they don't seem to realize that NT/XP/200x have nothing to do with Windows

95 at all. They are a completely separate family of operating systems.

I try to adapt as the situation warrants.

NT was built from scratch, as far as I know. There were disagreements on development directions between Microsoft and IBM, and Microsoft decided to go its own way.

You can run MS-DOS apps, too, but that doesn't mean that NT contains MS-DOS code.

I don't remember if I ever looked at compatibility stuff. I wasn't much interested in emulation.

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NT's multitasking is true, preemptive, and as good as any.

The present is 2005, not the late 90s, and OS/2 is history.

Explain the exact differences in multitasking between the two systems, and why OS/2 multitasking is "better."

Sometimes it's hard to keep track of the stories about whence NT was "stolen." One day it's VMS, another day it's OS/2 ...

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Oye! I was right, you don't know what pre-emptive multitasking is...... Wikipedia is not the source of all knowledge.....

It is not emulated, it is OS/2 base code that runs native. You must be aware of that.

As if bill gates would allow OS/2 emulation to be built into HIS operating system

Gates and co. did NOT write NT from scratch. They based much of it on the code developed at IBM for OS/2 when there was no mickysoft. Really, anyone who was around at the time, or who bothers to check even for a moment knows that. The only code any microsoft person ever wrote from scratch was Bob....

OS/2 has no useful graphical interface? Thanks, I will remember that one for a long time :-)

Either way, have a nice day. No point in wasting bandwidth on the same old stuff year after year. Doesn't really matter in the long run. Take a shot back to make you feel even. No big thing.....

Does anybody really 'know' what time it is?

Does anybody really care?

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I don't see the connection.

As I've said, I wasn't interested in compatibility stuff.

Why not?

"Based"? What does that mean?

Well, I _did_ check, and they _did_ write it from scratch. Of course they adopted ideas that had been used in other various operating systems, but every OS does that.

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about time?