Couple of questions about HD Loaders

[unclejun]

When the HDD in installed, the behavior of the power/reset button changes, I read it in a Sony document from the sdk iirc...
Press it once and the PS2 shutdowns, you can force the shutdown by holding the button down, it is not recommended though, corruption can occur.
To reset the PS2, tap the button twice rapidly.

[iCEQB]

Corruption to the system or to the HDD ?

[dlanor]

Corruption to the system or to the HDD ?

The PS2 does not have an operating system to get corrupted.
All it has is a bios, and that is stored in ROM so it can't get corrupted by normal drive access.

So what he was talking about is potential corruption to the HDD, which is particularly risky if you are using HDD-based VMC as well, since this involves write operations to the HDD, and not just read operations as is normal for simple CDVD emulation on HDD. But even with pure read access it can be dangerous to force power-off while a drive is in use, as this can cause the reading heads to 'bounce' on the disc surface, creating corrupting surface damage in each 'landing'...

That is why it is important to use normal 'shutdown' methods on computers (and the single-short-press on the PS2 power/reset button), so as to allow the normal system routines time to 'park' HDD access heads in 'safe' areas before turning power off.

This is a classical problem affecting all traditional HDD usage as well, and has been the cause of considerable design changes in later-day HDD models to minimize the risk of such damage. But the risk is still very real both for computers and gaming consoles, whenever sudden power spikes or power outages occur. I've lost several computer HDDs due to such events myself.

Best regards: dlanor

[alexo]

When the HDD in installed, the behavior of the power/reset button changes, I read it in a Sony document from the sdk iirc...
Press it once and the PS2 shutdowns, you can force the shutdown by holding the button down, it is not recommended though, corruption can occur.
To reset the PS2, tap the button twice rapidly.

Interesting. Can you point to the documentation that says it? Thanks.

[urbigbro]

That is why it is important to use normal 'shutdown' methods on computers (and the single-short-press on the PS2 power/reset button), so as to allow the normal system routines time to 'park' HDD access heads in 'safe' areas before turning power off.

This is a classical problem affecting all traditional HDD usage as well, and has been the cause of considerable design changes in later-day HDD models to minimize the risk of such damage. But the risk is still very real both for computers and gaming consoles, whenever sudden power spikes or power outages occur. I've lost several computer HDDs due to such events myself.

Best regards: dlanor

I understand that the best way to turn off the PS2 when using a HDD based game or application is to either IGR out of the game and then use uLE's or another homebrew's app to power off the PS2 via software, but what should we do when this is not available. For instance a game that is not compatible with IGR, using HDL, USBA, or a game just freezing hard?

Is holding down the PS2 power button still likely to cause the heads to park in unsafe areas and cause damage?
I of course never just flip the switch on the back when using the HDD.

[dlanor]

I understand that the best way to turn off the PS2 when using a HDD based game or application is to either IGR out of the game and then use uLE's or another homebrew's app to power off the PS2 via software, but what should we do when this is not available. For instance a game that is not compatible with IGR, using HDL, USBA, or a game just freezing hard?

Well, in such cases there is not much choice available. All we can do is to click the switch briefly a time or two hoping it will work, but if that has no effect we can only choose between using a longer press to force it off or let it remain frozen forever, which is not a real alternative (I'd rather crash the disk knowingly). But it is still a good idea to wait a few minutes to give the drive a chance to auto-park, if it has that feature (and many modern drives do).

Is holding down the PS2 power button still likely to cause the heads to park in unsafe areas and cause damage?

Not really likely, thought there is always some risk. But if you've waited long enough to be sure that the program really is frozen, then it is quite likely that the HDD itself will have auto-parked the heads already...

I of course never just flip the switch on the back when using the HDD.

Good, as that is the worst case possible.

One reason this is worse than forcing standby mode by long pressing of the reset/standby button, is because the physical backside switch directly interrupts the mains current feeding the switched power supply, and that can cause highly abnormal voltage spikes throughout the console. Hopefully damping capacitors will reduce that, but voltage spikes are always a bad thing, no matter how you look at it. Putting it differently, using that backside power switch has exactly the same effect as physically yanking out the power cord out of the back of the unit. And either way that sort of thing should only be done with the console already in standby mode.

Best regards: dlanor

[alexo]

My PS2 with a hard drive will only reset on a short press, the long press one is needed for shutting it down.

Also:

[...] it is still a good idea to wait a few minutes to give the drive a chance to auto-park, if it has that feature (and many modern drives do).

All modern drives auto-park on power off.
For example: http://en.wikipedia.org/wiki/Hard_di...oad_technology

[dlanor]

My PS2 with a hard drive will only reset on a short press, the long press one is needed for shutting it down.

That is how all PS2 consoles in the entire world work normally, before activation of the HDD drivers.
And this is true regardless of whether they have an HDD physically connected or not.

But proper activation of the HDD drivers modifies the response to that button, such that a single short press also causes power-off, but only after explicit termination of all HDD accesses (file closure etc), which should also include explicit parking of the heads.

Unfortunately the code to handle this is subject to crashing, like any other RAM-based software, and when such crash has occurred the brief pressing of the button has no effect at all. But the long button pressing still works then, because that is implemented in hardware/firmware, not software.

All modern drives auto-park on power off.

They try, but they are not perfect at it, unfortunately.

Those methods work best when the head is not really engaged in accessing data,
but power loss while doing that can still have very destructive results for the disk surface.

I should know, as I suffered two major crashes of this kind around 6-8 months ago.

One was due to abnormal voltage spikes on the local power grid, frying my main CPU and crashing some HDDs. Here a lot can be blamed on the spikes of course, as it was not just a power outage. In any case I then had to replace my main computer.

Then I had some simple but repetitive power outages one day some time later (new local power grid faults, but without spikes), resulting in additional HDD damage.

So no one can convince me that all drives today are fully protected against head crashing, regardless of when power loss occurs. I just don't buy that sales talk.

The only way to be fully safe at power off is if the head is already parked when it happens,
and when done properly as described before that will normally be the case. And this same reasoning (among HDD manufacturers) is also the reason why most modern drives do auto-park their heads during any long-ish access pauses.

Best regards: dlanor

[alexo]

Hi dlanor,

That is how all PS2 consoles in the entire world work normally, before activation of the HDD drivers.
And this is true regardless of whether they have an HDD physically connected or not.

But proper activation of the HDD drivers modifies the response to that button, such that a single short press also causes power-off, but only after explicit termination of all HDD accesses (file closure etc), which should also include explicit parking of the heads.

Interesting. How do I activate the drivers then?

Those methods work best when the head is not really engaged in accessing data, but power loss while doing that can still have very destructive results for the disk surface.

Um, no. The mechanism that parks the head is mechanical, not electrical.
Basically, a spring. When power is applied, the voice coil works against the resistance of the spring. When power is lost, the spring moves the head away. Another method is using the rotational momentum of the drive to move the head away. In any case, the head does not go down on the data portion of the platter when power is cut off.

I should know, as I suffered two major crashes of this kind around 6-8 months ago.

One was due to abnormal voltage spikes on the local power grid, frying my main CPU and crashing some HDDs. Here a lot can be blamed on the spikes of course, as it was not just a power outage. In any case I then had to replace my main computer.

Then I had some simple but repetitive power outages one day some time later (new local power grid faults, but without spikes), resulting in additional HDD damage.

With all due respect, but I don't think that you have the equipment to accurately diagnose the actual cause of the crash. A spike can forcefully drive the head into the platter, which is what probably happened happened in the first case. I don't know what exactly happened in the second case but the cause should have been something other than a power loss.

So no one can convince me that all drives today are fully protected against head crashing, regardless of when power loss occurs. I just don't buy that sales talk.

Nobody claimed total protection against head crashes. I said that they eliminated *one* possible cause of a head crash -- power loss. And that's engineering talk, not sales.

Here's an article I found from 2004:
http://www.pcguide.com/ref/hdd/op/actParking-c.html

[dlanor]

Interesting. How do I activate the drivers then?

Normally this should be done properly by whatever software is used to access the HDD, but the homebrew drivers used for this differ wildly, so not all of them work the same way, as originally intended. Some simply cause brief pressing of the reset/standby button to be completely ignored (eg: HDLD_svr), while others correctly cause a proper termination of all ongoing file access followed by powering off the console (eg: HDLoader).

Um, no. The mechanism that parks the head is mechanical, not electrical.
Basically, a spring. When power is applied, the voice coil works against the resistance of the spring. When power is lost, the spring moves the head away. Another method is using the rotational momentum of the drive to move the head away. In any case, the head does not go down on the data portion of the platter when power is cut off.

Such faith in the infallibility of these implementations is almost touching.
But with my experiences in tow I am unable to share that faith, regardless of your eloquence.

With all due respect, but I don't think that you have the equipment to accurately diagnose the actual cause of the crash.

I never claimed to make a detailed step-by-step diagnosis. I merely claimed to have seen what happened and the result thereof. And that is enough.

A spike can forcefully drive the head into the platter, which is what probably happened happened in the first case.

Yes, which is the kind of reason why I too said that the first incident could be blamed on those spikes. But it is even so an example of how an external power event can cause damage to the disc. And surely you too must be familiar with the fact that simply cutting off current to any circuitry containing inductors can produce voltage spikes...

So simply turning off the main power breaker while the equipment is running might in some circumstances cause harmful voltage spikes.

I don't know what exactly happened in the second case but the cause should have been something other than a power loss.

Never-the-less a power loss was the only external event that occurred, and the result was disk damage. Whether this was caused by a direct or indirect effect of the power loss is of course impossible to say with certainty, but the fact is that it occurred, and nothing you say will change that. Nor will it change the fact that similar events have happened, and continue to happen, for others than myself too.

It doesn't really matter one way or another whether the connection between cause and effect is direct or indirect. What matters is that this kind of power-loss can cause damage, and that the danger of such damage is higher if it occurs during active data access. So regardless of what protection modern drives contain it still makes good sense to continue with the same old protective measures as with older stuff, of making sure that all data access is terminated before we turn the hardware off.

Nobody claimed total protection against head crashes. I said that they eliminated *one* possible cause of a head crash -- power loss. And that's engineering talk, not sales.

A lot of it is engineering talk, of course, but I do not think that any honest engineer would claim 100% protection efficiency. And when that claim is made I do regard it as sales talk and nothing else.

Here's an article I found from 2004:
http://www.pcguide.com/ref/hdd/op/actParking-c.html

I don't care how many articles you find nor where you found them. Stating a claim over and over again does not make it true when the experience of many users is that the claim is overstated.

I am not alone in having lost HDD drives due to power loss incidents, it has happened to lots of people, and most likely to many in these forums too.

I agree that the improved protection against head crashing in modern drives is a very good thing, but it does not give the total protection against damage in power loss that you say.


For one thing, it should be obvious to anyone that during the act of writing data to the HDD surface any kind of interruption at all will prove fatal to the integrity of the data, which will then be crashed even if the surface itself is undamaged. And this kind of power-loss damage to data is something that no mechanical systems can protect against.


In any case, I don't think either one of us is going to budge on this, and I don't think we are contributing anything constructive to this thread. So perhaps it is best if we just 'agree to disagree' on this topic and drop it for now. OK ?

Best regards: dlanor