[gulmatan]

Hi all,

When you're done laughing, here's my post:

My theory is this:

1: user presses Play,

2: iPod gathers together upcoming song/songs and places them in RAM

3: Song currenty playing (and upcoming few in buffer) are played.

4: As current song is playing, iPod gathers new song and puts that in RAM buffer on the bottom of the lists of songs currently in RAM.

cycle continues from step 2

Am I right?

[Cold Warrior]

WTF is your point?

[applemacbook]

There is no "list" within the RAM. But you're correct that it caches the upcoming songs into the cache to reduce hard drive usage.

The RAM capacity is different for every iPod, so how many songs or minutes it caches will vary for every model.

[lamewing]

Originally Posted by Cold Warrior 

WTF is your point?

What is with the bad attitude and rudeness. Kiss your mother with that mouth?

[gulmatan]

Originally Posted by applemacbook 

There is no "list" within the RAM. But you're correct that it caches the upcoming songs into the cache to reduce hard drive usage.

The RAM capacity is different for every iPod, so how many songs or minutes it caches will vary for every model.

Thank you for the courteous response The "list" to which I refer to is this--when you set the iPod to Shuffle>Songs or any other of the Shuffle options, I surmise that when you start playing a playlist, since the Shuffle option is set, doesn't the iPod generate some sort of internal list (away from the user's view, of course) to go by as it's shuffle-playing the playlist of your choice? That's the list to which I am referring.

[Cold Warrior]

Originally Posted by lamewing 

What is with the bad attitude and rudeness. Kiss your mother with that mouth?

Spare me the lecture. The dude asked a lame question. He's a big boy who can take some peer feedback.

[analogika]

nm.

[lamewing]

Originally Posted by Cold Warrior 

Spare me the lecture. The dude asked a lame question. He's a big boy who can take some peer feedback.

OR you can act in a civil manner. I bet a dollar to donuts that you wouldn't respond to a stranger in person the way you did here.

It was hardly a "lame question". Consider that there are folks who are new to the forum or just have a question that they are not clear on. Are the forums not here but to help others? Or do you feel they are here for you to act in a manner you wouldn't dare do in public?

[mutelight]

Originally Posted by Cold Warrior 

WTF is your point?

Internet tough guy!

I remember thinking about that process too when I first got my iPod because I could hear/feel the HDD spinning down between songs.

[analogika]

The hard-disk based iPods work by spinning up the hard drive, loading whatever the next 64 or 128 (or however much RAM the thing has) MB of songs the user/OS have determined to be into RAM, and then spinning down the drive. As the RAM content is played or other content is requested that's not currently in RAM, the hard drive is spun up and that content loaded.

I assume the Flash-based players don't need to pre-load, but can play directly from the Flash memory.

[gulmatan]

Originally Posted by analogika 

The hard-disk based iPods work by spinning up the hard drive, loading whatever the next 64 or 128 (or however much RAM the thing has) MB of songs the user/OS have determined to be into RAM, and then spinning down the drive. As the RAM content is played or other content is requested that's not currently in RAM, the hard drive is spun up and that content loaded.

I assume the Flash-based players don't need to pre-load, but can play directly from the Flash memory.

Thank you for a quite detailed and very much informative explanation, Just what I needed to answer my question.

Originally Posted by lamewing 

OR you can act in a civil manner. I bet a dollar to donuts that you wouldn't respond to a stranger in person the way you did here.

It was hardly a "lame question". Consider that there are folks who are new to the forum or just have a question that they are not clear on. Are the forums not here but to help others? Or do you feel they are here for you to act in a manner you wouldn't dare do in public?

Thank you LW for the courteous defense of my asking a question, Besides, I thought this would be the perfect forum, among experts who could politely and intelligently answer questions no matter how basic or complicated. Thanks again LW.

[C.A.T.S. CEO]

Originally Posted by lamewing 

What is with the bad attitude and rudeness. Kiss your mother with that mouth?

Um, the OP's title is misleading, it says "What does a iPod do?" when it should say "How does a iPod play music?".

No need to fly off the wall like that.

[imitchellg5]

How mature of you all. C'mon guys, what's wrong with a few questions?

[Atheist]

Exactly... give the guy a break will ya. So the title of his post wasn't as explicit as it should have been.... what a bunch of freakin' prima donnas.

[abbaZaba]

scoundrels

[Nodnarb]

howstuffworks.com is a great website

Has all of the info you want, plus loads of other stuff you probably already know or don't care about

enjoy

[Gamoe]

Originally Posted by analogika 

The hard-disk based iPods work by spinning up the hard drive, loading whatever the next 64 or 128 (or however much RAM the thing has) MB of songs the user/OS have determined to be into RAM, and then spinning down the drive. As the RAM content is played or other content is requested that's not currently in RAM, the hard drive is spun up and that content loaded.

That's why indecision will shorten the battery life of an iPod. If you leave the iPod alone to play from the current selection (whether it be a play list or by artist, shuffle, or any other order) it won't have to spin up the hard drive as often, conserving battery life.

If, on the other hand, you are like me, and change songs often, it'll drain the battery more quickly. I'm not sure just how much this would affect flash-based iPods, though, though there is always some drain every time you interact with the iPod (it needs to process your clicks and, more significantly, turn on the backlight).

RAM is still separate from the flash storage, though, right? So, changing songs would still require some energy, though probably significantly less than spinning up a hard drive would.

[analogika]

Originally Posted by Gamoe 

RAM is still separate from the flash storage, though, right? So, changing songs would still require some energy, though probably significantly less than spinning up a hard drive would.

I'm not sure.

Is there a reason why Flash-based iPods shouldn't be able to read directly from flash memory?

Does reading from Flash memory use significantly more power than reading from RAM?

[Dork.]

The iPod is running some kind of stripped-down OS on its little processor, which requires some RAM to be there. Something has to accept user input and make the display, after all.

Flash chips are not necessarily as easy to access as RAM. Playing MP3's involve reading a little bit of data at a time and processing it in time to make the sound coming out of the device continuous. I don't know what type of Flash chips Apple is using in the iPods, but some flash chips may require you to read data a block at a time, and may not take kindly to reading that block a little at a time. So, it may need to be read a block at a time out of flash, and buffered in RAM so it can be retrieved and decoded at the rate it needs to be.

Reading from flash probably doesn't consume all that much power, especially when compared with SDRAM which needs refreshing every so often. (I don't have the relevant datasheets in front of me, though, so don't hold me to that.) I'm pretty sure, though, that writing flash consumes a lot more power. However, an MP3 player doesn't need to write to flash when it's not connected to a power source.

[applemacbook]

Originally Posted by Dork. 

The iPod is running some kind of stripped-down OS on its little processor, which requires some RAM to be there. Something has to accept user input and make the display, after all.

I disagree.
The NEW iPod has a stripped down Mac OS, but the older versions were based on an entirely different system that was developed solely for the iPod.

Flash chips are not necessarily as easy to access as RAM. Playing MP3's involve reading a little bit of data at a time and processing it in time to make the sound coming out of the device continuous. I don't know what type of Flash chips Apple is using in the iPods, but some flash chips may require you to read data a block at a time, and may not take kindly to reading that block a little at a time. So, it may need to be read a block at a time out of flash, and buffered in RAM so it can be retrieved and decoded at the rate it needs to be.

I would agree that reading from Flash is substantially slower than reading from Flash.
It would be interesting to see the technical specifications for the new iPods - how much RAM it has, what kind of processor handles the graphics, etc..

[Eriamjh]

Originally Posted by applemacbook 

I would agree that reading from Flash is substantially slower than reading from Flash.

I completely disagree with that statement.

[Dork.]

Originally Posted by applemacbook 

I disagree.
The NEW iPod has a stripped down Mac OS, but the older versions were based on an entirely different system that was developed solely for the iPod.

It's still running an OS, just not Mac OS.

[besson3c]

Originally Posted by C.A.T.S. CEO 

Um, the OP's title is misleading, it says "What does a iPod do?" when it should say "How does a iPod play music?".

No need to fly off the wall like that.

I hope that as you grow a little older the anal retentive streak you have adopted gets pushed aside.

We are very poor role models for you to be following, I hope you realize that.

[imitchellg5]

Us youngins are more mature than you old guys sometimes. It's okay though, everyone has their bad days.