PC still playing Amiga catchup

[Karlos]

So sorry, you still can't grasp the simple file I wrote and rather opted to be mislead by some speculator who is already known to have mislead people.  When you press the fire button and let go and move the joystick, you can go through a few states of a joystick that require millisecond accuracy.  In fact, it can be less.  Now your bullcrap about two clock crystals not giving exactly the same timing is just that-- a separate argument and just bullcrap since the crystals only need to be as accurate as to produce the timing needed for the system and there are ways to insure they all have consistent timing.  Perhaps, you want to read up on how they actually get Coppers, CIAs, Audio Interrupts, etc. to get the same timing rather than blurting out some blind assertion to mislead people.

Temper, temper. Just mirroring your pedantry. Struck a nerve, did it?

[koaftder]

He was lying (concocting things to confuse people) and you were biased enough to fall for it without any evidence.

No, he's not lying. He took at look at the data and came to the same conclusion that I did, he just managed to drop his post a few minutes before I got done with mine. I actually dumped your table into excel and did some analysis.

To begin with, you didn't disclose how you got this information. You didn't tell us what the other bits are for either. The first issue alone makes your data worthless. Another, more important issue is that you have no idea how often the software polls the port and you stated as such.

Your data shows state changes on the joy port with a time interval of 0.01 milliseconds. This is physically impossible for a human and mechanical switches are unable to guarantee a clean state at this frequency.  It's classic undebounced garbage signal noise. I see that you've slammed folks about one thing or another about the chipset, yet you seem to know nothing about basic hardware issues. For all your hemming and hawing about cycle count this and sync that on ancient hardware, you fail to unserstand how a contact switch works.

[kolla]

0.01 millisecond? Or 0.01 second?

[koaftder]

0.01 millisecond? Or 0.01 second?

The data the guy posted and is defending has sub millisecond entries. He's arguing that 10 microsecond state changes on the joy port are important for playing games.

[shoggoth]

Wrong.  When you move the joystick, left to right you go into a state of no-press for extremely small amount of time (sub millisecond); that's what you see there.  I only mentioned 1Khz; if you took that into account as relevant you would need much higher than 1Khz.  Your speculation that it's contact bounce is just that -- speculation.

No, it's fairly obvious that it's contact bounce:

239 0.034183 ms
231 0.011827 ms
239 0.011782 ms
231 0.034382 ms

1/(0.01ms / 1000) = 100000Hz. This is not joystick input from the user, this is contact bounce/noise. This is not speculation, it's an obvious conclusion based on your own readings. You on the other hand have interpreted this as "holy cow, this is accurate" - while it's actually not accurate at all.

[shoggoth]

If you sample at higher rates, you will capture more of the human reaction on the joystick than if you sample at lower rates.

That's true until you sample faster than the switch time of the joystick switches. Then you're recording contact bounce. Which you did.

[Karlos]

Thought experiment:

Suppose you took an analogue joystick and used the X/Y potentiometers to control an independent left/right output volume from a oscillator (generating a note at let say several kHz)  then fed that into your basic sound card and sampled this signal at 44.1kHz. You could then calculate the RMS intensity of each channel in frames of 441 sample chunks and use that (suitably calibrated) to represent the original X and Y potentials. 441 samples at 16-bit precision would be ample data to get a decent value for the RMS intensity of a simple tone in the kHz range.

That should be pretty damn close to 1kHz sampling of your joystick position

(note, simply sampling a DC potential across the potentiometers with a soundcard isn't likely to work well, or possibly even at all due to the frequency response of the sampling hardware. Not many record 0Hz too well)

I'm actually really tempted to try this for real now :lol:

[warpdesign]

That's funny

Once upon a time, Amiga was a superior machine (in terms of hardware) as anything else... So Amiga fans were using this as an argument for the Amiga's superiority.

But then, PC catched up, and even went beyond, with faster gfx, more colors, even smooth scrollings, etc... Sure, it took time. But meanwhile, Amiga only went from OCS/ECS to weak AGA.

And AGA was inferior to anything else, be it consoles of the time or even PC. So Amiga fans had to use another argument... So they switched to the OS, and the fact it was small, when compared with bloated Windows (or Linux,...). And could do preemptive multitasking while OS of the time couldn't (well, MacOS couldn't, but Windows had preemptive multitasking starting from Win95, although the full OS wasn't yet 32BIT).

Today, well... OS are still bloated, but processors are so fast and you have so much memory that's it's not really a problem, especially when compared to the services it gives you: 3D, Games, Video encoding/decoding, webcam, huge frameworks,... And all OS can do preemptive multitasking, even MacOS, yes!

And well, AmigaOS became bloated too: while original AmigaOS could run with as little as 256kb RAM, I doubt you could run the latest with less that 40Mb RAM... And that's without running the bloated browsers that can easily eat as much as 32Mb RAM for a single webpage ! So well... not only the OS isn't that light anymore, but it's also lagging in term of services, functionnalities, security, etc.. no memory protection, no resource tracking, no advanced 3D support (T&L ?), weak USB support (especially for OS4, since Poseidon is quite advanced I have to admit).. So you can't really use the OS anymore as an advantage, or you can use stupid things like "it boots fast"... but since you can reboot every hour or so because program x brought down the whole OS, I really don't see it as an advantage. The last time I rebooted my WinXP machine must have been 3 months ago... and it's no even long compared to today standards.. It's just normal.

As for the hardware, well, Amiga is still trying to catch up... lagging behind, because there's no development made in desktop powerpc. Cause there is no market..

So well, what's staying ?

Well, arguments as stupid as "you may poll the joystick port 1000 times a second, the PC cannot". Well, it's certainly *true*. But it is so useless that no one in the entire Amiga's existence ever mentionned or used it. No one but you...

So really, who cares ?

Now, if people could simply accept the fact that the Amiga has been catched up in every aspect, we could move on.. and work on something great, nice... a true NG Amiga... it surely wouldn't catch PC development. That can't happen anymore. But could be fun, interessting, *fresh*,... like the original Amiga actually.

Running ScummVM+SDL ports on lagging hardware, crashy, old, ugly (yes, grey 2-colours GUI was certainly ok on a TV, but on a 20 inch 16/10th monitor and such powerfull gfx boards you can certainly o better) OS isn't really fun...

Playing with a nice true NG frehs OS on powerfull common/cheap PC hardware could be interesting though... Look at Apple: seems like fun is possible with PC hardware as well... and I ask you to show me the difference between a PPC-Mac and an Intel one without opening it... except that the Intel one would be faster of course.

That was my two cents. You can keep on posting detailed reports on how you can poll the Amiga joystick port faster than anything else, but this won't change anything to that...

[amigaksi]

Yes, but the issue here is: "who cares?".

Maybe you're the only one all over the world. Doesn't this suggest anything to you?

If you don't care about things where Amiga has an advantage, then what are you arguing about in this topic.

[amigaksi]

Temper, temper. Just mirroring your pedantry. Struck a nerve, did it?

No, you didn't answer the point.  What makes the timing consistent throughout ECS/AGA/OCS if crystals are so different as you claim?

[amigaksi]

The data the guy posted and is defending has sub millisecond entries. He's arguing that 10 microsecond state changes on the joy port are important for playing games.

You are drawing that conclusion by distorting the truth.  I only stated 1Khz but if you think about it you can see that someone releasing a fire button and moving joystick can have sub-millisecond intervals as well.

[the_leander]

No, you didn't answer the point.  What makes the timing consistent throughout ECS/AGA/OCS if crystals are so different as you claim?

Erm, as was pointed to in Karlos's drumbeat example:

There is no consistant timing


Now watch and learn as the rest of your argument is slowly chewed up and spat out.

[amigaksi]

No, he's not lying. He took at look at the data and came to the same conclusion that I did, he just managed to drop his post a few minutes before I got done with mine. I actually dumped your table into excel and did some analysis.

To begin with, you didn't disclose how you got this information. You didn't tell us what the other bits are for either. The first issue alone makes your data worthless. Another, more important issue is that you have no idea how often the software polls the port and you stated as such.

Your data shows state changes on the joy port with a time interval of 0.01 milliseconds. This is physically impossible for a human and mechanical switches are unable to guarantee a clean state at this frequency.  It's classic undebounced garbage signal noise. I see that you've slammed folks about one thing or another about the chipset, yet you seem to know nothing about basic hardware issues. For all your hemming and hawing about cycle count this and sync that on ancient hardware, you fail to unserstand how a contact switch works.

You didn't plot the data where the switching does occur without the submilliseconds intervals:

239 154.648544 ms
255 572.020930 ms
251 797.851018 ms
235 15.316622 ms
239 174.151571 ms
255 253.714007 ms
247 63.774948 ms
231 109.837404 ms

You're only showing part of the data.  And your distorted conclusion that I'm talking about UAE is your speculation.  I never mentioned anything about UAE in this topic nor EVER used it in my life.  Stick to reality and drop the bias.  I don't see why an emulator could not handle 1Khz joystick input.

[Karlos]

We're yet to be convinced that:

1) Any amiga game, other than your code, samples the joyport at this rate.

The one example I can think of where high joystic sampling rates may be used would be the ZXAM tape interface.

2) That the ability to sample the joystick represents a genuine advantage. Your sample data suggests that you are able to observe the electrical properties of the micro switches as they close and open. I'm certainly not convinced that this resolution is useful unless you intend to produce time a averaged sample of the observed state at a lower resolution. For example, averaging the entire set of samples at 1kHz every frame into a value that you assume is "on" for the frame if more of the samples were in the on state than the off state. I'm not convinced any game does this. It more likely reads a sample once a frame and moves on.

3) You can't really infer what the sample rate of an application is just by attempting to sample the signal yourself and reproduce it the behaviour of the original application from it.

What you should try is sending simulated pulses at different rates to the joyport from another device from which you can control the pulse of and see wether or not the game is capable of responding to it in a predictable fashion.

[amigaksi]

Erm, as was pointed to in Karlos's drumbeat example:

There is no consistant timing


Now watch and learn as the rest of your argument is slowly chewed up and spat out.

He hasn't proven anything about the timing of audio interrupts, CIA interrupts, Copper timing being different or varying over time.

You don't need to reference him; I read his posts.

[the_leander]

He hasn't proven anything about the timing of audio interrupts, CIA interrupts, Copper timing being different or varying over time.

You don't need to reference him; I read his posts.

If there is variance of clock speed (even by a fraction of a second) between two otherwise identicle systems using the same cycle, both cycles will still be identicle, but the timing will be different. This is demonstrable for anyone who owns more then one Amiga, even of the same model.

You're mixing up your definitions again, I personally think deliberately here.