If one OS is clearly noticable faster than another OS, what are the causes?

I think it's because of the memory management but he says it's about speed; I'll just use his quotes because I actually don't understand the guy totally:

"Also, your claim above, how the speed difference in OSes is with memory management. Thats not true either. All the commands to the processor are made at Compile time. That means, its up to the Compiler how memory is managed in each program, and how each command is done within the processor."
I think that it only affects programs individually and the OS with his program slicer/process manager has the final word about it.

The initial thing was about Win XP vs Win 2k. And he thinks that 2k is faster because it's a faster OS than Win XP. (His reason for being faster is because it has more speed )

What you think of this academical computer science student?

Faster in what way, exactly? Do you mean in terms of how long it takes for a program to load? How fast it draws things on the screen? How quickly it can solve mathematical problems or finish a 3D rendering? How long it takes to open, save, copy, or delete files? How many frames per second you get in games?

There are a lot of factors that influence the "speed" of a computer. Hardware is probably one of the most important - what speed your CPU is, how big its cache is, how much RAM you have and what speed it is, how well your motherboard integrates with all your other hardware, the seek time of your hard disk, and so on. The operating system can be a factor, since it handles most of the interaction with the hardware, but a good operating system can't really make up for poor hardware. And of course, the way a program is written has a significant effect, as well; if a program does things efficiently, it will be "fast".

Another thing...the compiler certainly has say over when and how much a program asks for as far as memory goes, but it is not the compiler but the kernel that decides what memory a program gets, and where it comes from....

I think he has no idea of how an operating
system works :}



Cheers,
Tink

Also depends on time since install.

Due in part to fragmentation, but mostly the bloody registry - a freshly installed (same hardware / software / tweaks) windows system will outperform an identical box that was installed "x" months ago.

Is it possible for two different programs written by two different authors to take different amount of time to accomplish the same task? Sure it is. One author may write very efficient code while the other may not. Now expand the concept of the operating system to just a large collection of programs, and make the same assessment. It's possible for one to be faster than the other.

Is one OS always faster than another? Maybe. One might one thing better while the other is faster at another task.

Thanks for all the response already!

Wapcaplet; I'm not talking about RAM or hardware (I'm not retarded lol); but it simply comes down to this (so forget about hardware; they are the same on both computers):

IF Windows 2k goes notably faster than Windows XP in executing an identical program on identical computers..... What can be the causes or do you think it's impossible? I think it might be possible but then only because of memory management.

What do you think about it?
A) It's impossible
B) It might be possible but if it's noticable faster than it must be memory management.
C) It might be possible because "2k is simply faster than XP".

Tink; this guy(Tarential) read the topic and he thinks your comment is directed at me. Could you plz name the person (Hermes=me) or Tarential(him) for who the post was directed at?

The answer, in your A), B), C) Multiple choice is D) none of the above

There is more then just memory management involved, there is process management, and other things going on that can effect it.

From my understanding, and this could be totally off kilter, is that XP is simply a bloated version of Win2k. It's based off the Win2k kernel, but it also has other crap that you don't necessarily need in it. Plus, it has more background processes than Win2k. I would have to say, and this is all speculation, since I havn't worked much with Win2k, is that 2k is quicker than XP because it's more bare and efficient. XP simply has too many background processes, and stresses too much simplicity that it takes over the computer. Much like what cars are doing these days, taking away the thrill of driving....

Well, if it actually happens, then nobody can really claim it's impossible But if an "identical" program can run on both of the operating systems, then they can't be all that different from one another.

Memory management is just one of the factors affecting perceived speed. Again, it depends on what kind of speed you're talking about; you didn't specify what kind of program it is, or what the program is doing. If it's a program for copying files, and on Windows 2K it copies them twice as fast as it does in Windows XP, then it probably has more to do with buffering and the efficiency of the filesystem and related file I/O than with memory management. If it's a 3D application and you're talking about frame rate, it probably has more to do with how well the OS interfaces with the 3D hardware.

It is rarely as simple as "2K is faster than XP", though. Sure, I can imagine a scenario in which operating system A is written so much better than operating system B that practically everything is faster on operating system A (not naming names here, of course, ahem), but there is probably also always a pathological case in which operating system B outperforms operating system A. For example, a program that was written specifically for B, in the same inefficient way and using the same inefficient functions, might do better on B than on A.

You could also make a case like "Windows XP is faster than DOS", but if you tried to run them both on a 386 with 4MB of RAM, DOS would probably perform better

If the things you are comparing are Windows XP and Windows 2k I am pretty sure the main difference is the fatter user interface and the other added processes that run in XP vs. 2k. It is hard to say without actually seeing the source code, but the kernel for Win2k reports as being NT5.0 Build blah blah blah and WinXP resports as being NT5.5 build blah blah blah. I am guessing how they do things like process management and memory management, while maybe not being exactly the same, is pretty darn close. People give MS a lot of grief but I don't think they would have put a worse memory management system into the WinXP kernel then the one they already had for Win2k.

I am going to go ahead and quote a book that perhaps you and this "computers science" student should pick up and read: Applied Operating System Concepts, by Abraham Silberschatz, Peter Galvin, and Greg Gagne.

"We can view an operating system as a resource allocator. A computer system has mayn resources (hardware and software) that may be required to solved a problem: CPU time, memory space, file-storage space, I/O devices, and so on. The operating system acts as the manager of these resources and allocates them to specific programs and users as necessary for tasks".

Now that was a very general definition given on the 4th page of the introduction to the book, but the point of giving it to you is to say that an operating system is in charge of doing quite a lot of things. The methods operating systems use to do these things can very tremendously from one OS to another. This often results in some systems doing some things "Faster" and others doing other things "Faster".

If you are really interested on specific differences between different OS's the book does a case study on UNIX, Linux, and Windows NT and how they choose to do things.

jtshaw is right. Speed is a lot of things combind. But I doubt that Win2k and WinXP vary very much from each other as far as i/o, memory, process, etc.. mgmt. Why would Microsoft redesign everything for XP??? It works very well in 2k, and I am sure they paid quite a lot of money to get it to the point where it is. You don't make billions of dollars without being cheap. I doubt the code for a "message box" has changed very much from win95 to xp. The main differences come in extra features for easy use. Disable pretty much every "extra" feature of XP and 2K and you'll find XP does perform at the level of 2k. I am sure that XP and 2K's memory management are nearly identical as well.

Ok; sorry; this guy changed subjects now; he's now about the compiler; he says:
"You go like this:
"int i;"
The compiler translates this into machine code. Tells the machine to set aside a certain number of bits for an int. So yes, the compiler controls memory usage, as does, in respect, the programmer."

I tried to explain him 10 times that a compiler doesn't do any kind of memory management; but he keeps saying it! He think I know nothing about computers and it's annoying. Can anyone say that I'm right and that compiler has nothing to say about the OS' Memory Management?