Open-ps2-loader: ext2 support from E2OPL or exFAT

[eadmaster]

Backport the changes made in this fork.

Key advantages over FAT32:

• No file size limit
• No need of defragmentation

Probably the best choice over NTFS and exFAT.

[sp193]

The latter is not an advantage of the EXT2 filesystem itself, but the author added logic to handle the filesystem blocks. I was skeptical about whether he really managed to achieve that with no loss of game compatibility, since I once tried to shrink the FAT32 part of the USBHDFSD driver to being as small as possible and some games stopped working as a consequence. When I did that, I found that even adding a 512-byte buffer for storing a sector and the logic for handling the filesystem, would cause some games to stop working due to a lack of memory...

A minority of users use an OS that supports EXT2 natively.

[rickgaiser]

When I did that, I found that even adding a 512-byte buffer for storing a sector and the logic for handling the filesystem, would cause some games to stop working due to a lack of memory.

Are you sure it was becouse of a lack of IOP memory? I remember we had a conversation about this once. SLPM-66438 "Melty Blood Act Cadenza" is the game that wasn't working, but that same game was working with ETH just fine. I can test this game again with a large (64KiB?) buffer added to iop-core?

The HDD (PFS) driver is passed an array of 65 partitions/fragments:
https://github.com/ifcaro/Open-PS2-Loader/blob/ad182dcf95e3322206f5c2f5ced99666ac1621f8/modules/iopcore/cdvdman/atad.h#L84
https://github.com/ifcaro/Open-PS2-Loader/blob/3b37ef7f250ca85e03cd86eacb9e060d8f6a3413/modules/iopcore/cdvdman/device-hdd.c#L42

I've tried to do the same before for the usb mass (BDM) driver. My intention was to use it with PFS, FAT32 and EXT2 (also inspired by e2opl), but in theory any filesystem can be used.
The GUI simply passes the fragments, and when more than 65 fragments are detected an error must be shown to the user, requesting it do defragment the drive. The in-game driver is only aware of fragments and doesn't need to know anything about the filesystem itself.

[Velocet]

exFAT would make more sense than anything else:

• Supported on every major OS (Windows, Linux, macOS, Android, iOS, etc.)
• Available implementations: http://elm-chan.org/fsw/ff/00index_e.html

The mentioned implementation seems pretty nice as it doesn't consume much resources...

[hardlevel]

Hi, sorry for opening this issue again...

But just a crazy idea... Is possible to use the same fs used in internal hdd, the pfs, but on usb?

If this was possible, it could solve many problems

[rickgaiser]

Not so crazy at all. BDM was created to separate the block devices from the file systems. If this is also applied to PFS and HDD, then it would be possible to use PFS on USB. Or FAT32 on HDD. Or any other combination.

[hardlevel]

I know that pfs can fragment too, but much less than fat32... this may be a good solution, if OPL could support two formats for usb, fat32 and pfs would be amazing, considering that we already have tools to install games in this format...

[AKuHAK]

There is no benefits in using any other filesystem cause of possible fragmentation. Specially pfs, which is too specific and doesn't have many pc side utilities.
It is possible to use device without filesystem at all, just directly write ISO files and then calculate LBA offsets. @sp193 oneday worked on this, but stopped, I dont remember why (maybe no benefits in comparing with non-fragmented fat32).

[sp193]

We don't use PFS for games. It's actually a proprietary filesystem that once belonged exclusively to HDLoader. If a different filesystem is used, then there's also a question if anyone is actually interested in using yet a different fileysystem, only for the PS2.

I did try to add a micro FAT32 driver to OPL before. But stopped since I couldn't get it to work desirably, which I believed was due to a lack of memory. But as you know, @rickgaiser has a different view and I don't know why our results just differ. Neither do I remember the exact observations from what I did back then, which was 2014. It's not because FAT32 results in more or less fragmentation, but we just did not want to support a full filesystem driver - ostensibly due to memory and speed requirements.

@AKuHAK I remember once having an idea like that, but I don't remember telling many people that I wanted to try it. The concept sounds like the HDLoader filesystem. But if I did, then idea could have been thrown out, as not many people seemed to be interested in yet another fileystem; that would require totally different tools, not compatible with other game loaders (or just older versions) and the space cannot be used for other things (outside of the PS2). However, I conducted no study, and perhaps just got the idea that it'll be unpopular, from the few people I interacted with.

[ahmedmoselhi]

@sp193 one other thing to take care of that may make difference using other file systems.. i have got 128gb didcated for ps2 games but when i try to load any game i stuck at white screen after loading . the games are placed on usb using usbutil app and no fragmentation found.. when i try to place the whole iso file in opl dvd folder game load successfully! but i have limitation of 4gb file size of iso so using other file system can solve this issue

[DraconicNEO]

I find it funny how backup loaders on Wii have so many supported file systems but OPL a utility on PS2, which is by the way more popular than the Wii by a long shot and it still only supports Fat32, doesn't even support Ext file systems.

[DraconicNEO]

A minority of users use an OS that supports EXT2 natively.

It's still good to have versitile file system support. Also there's an Ext file system support plugin for Windows.