how dose ESR work?

[angelwolf71885]

i know you need to patch a game in order to get it to work with either a chiped or soft-modded ps2

but how dose it work?

like if i put a patched burt game into the ps2 then turn it on with FMCB automatically check the disk to see if its patched then launch the game?

and also can a PS2 even remotely launch a burnt un-patched game WITHOUT swap and without a chip and without ESR?


ive searched this forum high and low and cant find ALL the info im looking for

thanks for your time

[adey]

As far as I'm aware, you don't need to patch burnt games, for them to work on a chipped ps2, you are correct though in the need for patching for use with ESR.

I'm pretty sure that there is no way to play a backup, patched or not, on an unmodified ps2, unless you use a swap method.

When you have FMCB & ESR installed to a memory card, you simply insert your patched disc and off it goes. I prefer the gui version personally, when testing a freshly burnt disc I've found it helpful, but with the non-gui version, it just boots straight into the game.

Hope I covered everything.

[angelwolf71885]

As far as I'm aware, you don't need to patch burnt games, for them to work on a chipped ps2, you are correct though in the need for patching for use with ESR.

I'm pretty sure that there is no way to play a backup, patched or not, on an unmodified ps2, unless you use a swap method.

When you have FMCB & ESR installed to a memory card, you simply insert your patched disc and off it goes. I prefer the gui version personally, when testing a freshly burnt disc I've found it helpful, but with the non-gui version, it just boots straight into the game.

Hope I covered everything.

i appreciate your response it clears alot of things up
i have a bet with my cousin that you have to patch the backups in order for them to work
or use HDL


hopefully dlanor can give a great detailed response like he likes to do LOL

[TehJawknee]

Actually, HDL will go ahead and load your ESR patched games, too. Patching your games is a good idea regardless of what you're using to run them. It doesn't hurt playability.

[dlanor]

i appreciate your response it clears alot of things up
i have a bet with my cousin that you have to patch the backups in order for them to work
or use HDL

Then you will need to modify that bet (so it applies only to burned discs) or forfeit, as OPL (Open PS2 Loader) is able to run games in exactly the same way as HDLoader does, and is also able to run games over LAN from a PC. Of course, the games do have to be installed to a fileshare folder on that PC for this to work, using installer methods similar to those for USBAdvance/USBExtreme, but these installed games do not need any patch changing the content read from the original disc. So technically I'd say your bet is already lost...

hopefully dlanor can give a great detailed response like he likes to do LOL

For the subject of burned disc backups going into the deep technical details would be pointless as their effect is well known and crystal clear. Booting burned discs requires one of the following:

1: Special developer/debugger console
2: Modchipped console
3: Discswapping method (like SwapMagic et al.)
4: ESR/Memento and using patched backup discs
5: Console emulator on a PC

These are all methods I know of that work today.

The only additional way I see of running an unpatched burned game backup disc with an unmodded normal console (but with FMCB for homebrew access) would be to make a special OPL loader core interacting with a special server on a PC, allowing you to put the burned disk in the CDVD reader of that PC and have the special server make the disc contents appear as a suitable fileshare on the LAN.

Custom loader cores already exist that can use normal ISO files, so using raw CDVD disc content the same way is not all that far off, though that will require some additional PC-side software (to make the disc appear as a fileshared folder containing an ISO file).

However, I see little point in doing this, as it is much more convenient to just fill up a large HDD partition with installed games, which are then available to any console in the same LAN running OPL. This is how I do it myself with over 150 games in a single collection that is accessible to all of my three consoles over LAN.

Best regards: dlanor

[angelwolf71885]

thank you for the reply
but do those burned 1 to 1 backups of ps2 media require patching

for example i copy my game from PS2 media to DVD-r media
will it just work? or dose ESR come into play automatically if it detects an ESR patched disk?

on chiped consoles or do they just do the memory patching on the fly because they already have the bios/FW by the balls? IE because a mod chip is a memory injection device

also dose HDL apply patches? or do they have to be patched even if backed up/installed with HDL?

[dlanor]

thank you for the reply
but do those burned 1 to 1 backups of ps2 media require patching

I'm not even sure what you mean by "PS2 media".

An HDD in a PS2 is a form of PS2 media, an MC is also a form of PS2 media, and so is a USB drive when it is connected to a PS2. Anything you can read some file from or write some file to using a PS2 console is some form of PS2 media.

for example i copy my game from PS2 media to DVD-r media

I assume that you here use the term "PS2 media" to mean a pressed DVD disc holding an original PS2 game. So that is the assumption I will base my reply on.

will it just work?

No. And a full '1 to 1' copy is impossible, for several reasons. An original pressed discs contains readable fields that lack a writable equivalent on a burnable disc, and there is also no way to hide the fact that the disc is a burnable type from the CDVD mechacon in the PS2, which is the unit that either permits or forbids further access to a disc by the PS2 programs (games or homebrew).

That is in fact what ESR uses to its advantage, as the ESR patch camouflages the disc so as to make it appear to be (as far as the mechacon bothers to check) a disc containing material of the only kind for which the mechacon will permit a DVD-R disc to be used, namely a DVD-Video movie.

The ESR patch modifies the UDF section of the disc, which is what the mechacon checks, to make it appear exactly as a very small DVD-Video movie. The mechacon then allows programs (such as the ESR driver) to access the disc, in the belief that it is just a movie backup, even though the ISO9660 section of the same disc still contains all the game files. This in itself would not quite suffice to make the game run, as that still requires access to the original (now hidden) UDF content, which is therefore provided by the ESR driver, since this knows how that content was hidden. So with the ESR driver active, all high-level parts of the system will see the disc as identical to the original game disc, with only the low-level mechacon believing that the disc is a DVD-Video movie.

In addition to this, some very few programs, such as FMCB and uLE contain special code to identify if a disc in tray is ESR-patched or not, so as to decide whether or not to invoke the ESR program when a disc is to be booted.

This is how the ESR method of running backups really works (minus the really deep techie details, which I will not even try to speak of here).

or dose ESR come into play automatically if it detects an ESR patched disk?

ESR is never 'automatically' invoked unless you have some software running that is able to invoke it (such as FMCB when booting, or uLE when using its "PS2Disc" command), and it is then that software that does the detecting, and decides whether to start ESR. (ESR itself has no way of doing it. It is not running at that time.)

on chiped consoles or do they just do the memory patching on the fly because they already have the bios/FW by the balls? IE because a mod chip is a memory injection device

This is not just a case of memory patching, but without going into deeper details it is essentially correct that a modchip does have the bios/FW (and some hardware) 'by the balls' as you say. These methods have absolutely NOTHING in common with ESR.

also dose HDL apply patches?

No. ISOs installed for HDL are not inherently patched, unless the user does so before installing, to get around some incompatibility problem of HDL. The patch work of HDL is done dynamically at runtime, when it emulates a CDVD driver and interferes with many other operations to prevent the game from reloading various driver modules (which would kill HDL). This patching affects only in-memory data or file buffers, so it has nothing to do with ISO patching.

or do they have to be patched even if backed up/installed with HDL?

Some games need various patches, but this is not in any way related to ESR patches.

Best regards: dlanor

[angelwolf71885]

thank you so much you have answered all my questions
if there was rep here you would have a ton of it

while i may not of won my bet i was certainly correct that with FMCB you need patching OR OPL/HDL

and thats good enough for me

[ffgriever]

To be true, ESR doesn't really touch the UDF filesystem at all. It is patched only to fool the mechacon. All the games use the ISO filesystem. ESR is just a proxy to translate some of the calls and make sure the game itself won't know it's running from a DVDVideo disc.

First, it hooks some calls to always return "proper" PS2DVD disc is in drive (actually, not always, as it affects only cases when DVDVideo is in drive... with the spoof option on, it even returns that there is PS2CD in the drive).

Then it searches through the IOP memory for direct reads/writes to the CD/DVD registers. Instead of the reads/writes it patches in some static loads/stores (or inserts calls to the spoof function).

Now comes the most important part. If DVDVideo is detected, some of the functions are not available (mechacon will simply discard it, returning empty or unchanged buffers). This is where the proxy stuff comes in. It intercepts the calls to the unavailable functions, uses the ones that are available, alters the result to match the needed function and returns it to the caller.

Sometimes it requires to invoke some other functions many times. This leads to the problem, that we have to alter the way CD/DVD interrupts are handled, so we need our own handler to dispatch all that, then return to the real one if everything is done (it is important when the game waits for the data to be read, so if we would simply call some of the read functions few times, it would signalize that the data is ready in the memory after the first one, so it would most likely crash, as the memory is just partially filled). Unfortunately the buffers needed by the functions available and required differ a little bit, as the size of read sector does change in these functions. So ESR uses as much of the originally allocated (by the game read engine, cdvdman itself, sound engines, etc - simply, whichever buffer is supplied to the read function) memory and allocates the missing one (this helps to save a lot of memory on IOP side - sadly, only 2MB - but causes some additional problems if the read functions have to be invoked more than once). Fortunately, it's not the case with the newer games (IOPRP270 and newer).

All in all, the job is done. The game doesn't know the situation it's running in is abnormal, everyone is happy.

To be true, game developers could block ESR use quite easily, but they didn't do it for (most likely) few reasons:
1. It seems sony doesn't allow developers to do this kind of low level stuff, as it might affect compatibility with various console models,
2. At the time the ESR came out, there were not really much of new PS2 games releases (or some crappy, low budget games were released),
3. Sony had patched the bios to not allow fmcb/memento to work, thus disabling the easiest methods of launching ESR (the ESR itself works just fine on the new consoles, you can use eg. swap magic's mass/mc homebrew launching options to launch ESR - pointless you say? not quite, as this way you don't have to do the usual swaps, blocking sensors and such, simply launch ESR from mass, then open the cover, put ESR patched disc in and play).

Hope that answered some of your questions.

[dlanor]

To be true, ESR doesn't really touch the UDF filesystem at all.

I just wanted to add that I naturally am aware of this. ESR leaves all the UDF filesystem intact, except for patching what is needed to prevent the mechacon from seeing that it is there at all, instead making it see only the dummy DVD-Video stuff.

That is what I meant by saying that the original UDF filesystem is 'hidden' by the ESR patch.

As for the method of ESR 'unhiding' it to make the game work properly, I simplified that part a lot, just to keep the basic principle of it understandable for the non-programmers.

Best regards: dlanor