Are SD card and USB HDD interchangeable in HB development

Hi,

Currently I'm using a SD card to store a Doom 3 PK4 file. However, it takes minutes to just parse the files in the PK4. I know my SDcards only read/write about 100-150 KBytes per second, so I'm wondering if I can easily continue my development using a USB HDD instead of the SD card. My guess is that it will load files much faster then when using SDcard

I currently upload the Doom 3 executable (far from finished ofcourse) to my Wii using Wiiload Java client and the app then opens files from SDcard.

Basically I have the following questions:

* Does lib-ogc support USB HDDs? If so, what version do I need?
* Do I have to change my (hardcoded) file locations? For example, do I need to use a different drive name (i.e. instead of /apps/DoomGX /USB0/apps/DoomGX)

Does anybody use a HDD to develop any apps?

Thanks!

Danny

I remember reading you should be using full paths even when loading from SD (sd:/apps/DoomGX).

I would guess standard single-partitioned USB/FAT HDDs are supported with your current setup (usb:/apps/DoomGX). But you should be able to see the problem there: HDDs are more likely to have partitions (some of them formatted as NTFS or extN) so you would need to parse the partition table and act accordingly (adding libntfs and/or libextfs if you want to support those). You obviously need to handle it in code because the average user has no idea of whether his HDD is a standard single-partitioned USB/FAT HDD.

Also, USB2.0 is only "supported" when running on IOS58.

I have never plugged an HDD to WiiMC but I saw there's code to handle all this there. Reading partition table, mapping partitions to usb0, usb1, detecting/guessing loading/saving device, checking the IOS version, etc. That is the code you should be reading if you really think this is needed.

From what I've read, I believe if you use "fat:" instead of either "sd:" or "usb:", it'll default to SD and then go to USB is SD isn't present. Not 100% sure. I think if you want to specify which to use though, you use either "sd:" or "usb:", depending which you want to use.

I often use relative paths ( data/file.txt ) when publishing my homebrew. So that if the person installed it on a SD or USB HD it will still find the files (and not be trying to load data files from the sd:/ all the time ). The only downfall of this is that when using wiiload the root directory is always "/", so I end up having to use paths like "/app/mygame/data.txt" - EVERYWHERE but this doesn't work in all cases because some add-on libraries (such as Lua) doesn't care about chdir()/current directory when loading includes.

Thanks! Useful link. I'm currently on IOS38 (never updated it) so'll try IOS58 on my other wii first:)

Re partitions and such: you don't need to worry about that unless you specifically want to support mounting more than one partition at a time or partition types other than FAT (ext2/3, ntfs etc.). Otherwise libfat is able to parse the MBR and mount the first found FAT partition without the need for any extra code.

"fat:", "sd:" and "usb:" are not strict names, they can apply to any device and they are not always setup automatically for you. It mainly depends on how you use libfat:
- fatInitDefault() will attempt to mount the front SD slot, a USB HDD, an SD gecko in slot A, an SD gecko in slot B (in that order) using the device names "sd", "usb", "carda", "cardb". It will also try and parse the first command-line argument passed to your app to detect which device should be the default path (referenced by "/").
- fatInit() works the same way but lets you set how many cache pages each device should get and specify if the default path should be changed.
- fatMountSimple() will let you mount a single device with a given device name. So you could use this to try and mount the sd card using the name "fat", and then only if it failed attempt to mount a USB drive using the same "fat" name. Then you could use "fat:" everywhere in your code without worrying about which device it actually refers to.
- fatMount() is similar to the above but also lets you specify a specific starting sector for the partition, how many cache pages should be used and how many sectors each cache page should have.

Lastly: don't expect USB to perform much better than SD, there's actually not much difference between them unless you've got a really old SD card.

Tueidj, thanks man! Do you know any speed numbers on newer SD cards? I'm using a 5 year old 2GB card I guess. The speed I'm currently experiencing is real slow so anything that is faster is appreciated.

fatInitDefault seems to work only if the Wii sd card is inserted.

fatInitDefault is always false if I launch the dol file from an USB device and the SD is not inserted.

Is this the correct behaviour?

Quote
oibaf
fatInitDefault seems to work only if the Wii sd card is inserted.

fatInitDefault is always false if I launch the dol file from an USB device and the SD is not inserted.

Is this the correct behaviour?

the same here =)