Cafe OS
Cafe OS is the operating system running on the PowerPC in Wii U mode. It consists of the Cafe OS kernel, the executable loader, and system libraries. Unlike on the Wii, where games ran with full hardware access, Wii U applications run under the supervision of the kernel, isolating them from each other. All applications are modified ELFs, as are the libraries themselves, and applications dynamically link with them to gain access to OS services. Cafe OS also contains a few system processes, like the home menu and error handler.
Architecture
Kernel
Loader
Libraries
Cafe OS applications dynamically link with system libraries to get access to OS services. These OS services include memory management, graphics, audio, and controller input. All libraries are RPL files, a modification of the standard ELF format with compressed sections and more Windows-like dynamic linking. The main system libraries are listed below, with some having their own pages of documentation:
- avm.rpl
- camera.rpl - Gamepad camera
- coreinit.rpl - Kernel, memory, and FS
- dc.rpl
- dmae.rpl - DMA (Direct Memory Access)
- drmapp.rpl - Digital Rights Management
- erreula.rpl
- gx2.rpl - Graphics
- h264.rpl - Support for H.264
- snd_core.rpl - Audio
- vpad.rpl - Gamepad input
- lzma920.rpl - LZMA compression
- mic.rpl - Gamepad microphone
- nfc.rpl - low level NFC library
- nio_prof.rpl
- nlibcurl.rpl - libcurl
- nlibnss.rpl - libnss
- nlibnss2.rpl
- nn_ac.rpl - Nintendo Network Auto Connection
- nn_acp.rpl
- nn_act.rpl - Nintendo Network Accounts
- nn_aoc.rpl - Nintendo Network Add-On Content
- nn_boss.rpl - Nintendo Network BOSS (Streetpass)
- nn_ccr.rpl
- nn_cmpt.rpl - Nintendo Network Compatibility ???
- nn_ec.rpl - Nintendo Network E-Commerce
- nn_fp.rpl - Nintendo Network Friend Presence
- nn_hai.rpl
- nn_hpad.rpl - Something related to controllers
- nn_idbe.rpl - Something related to crypto/downloads
- nn_ndm.rpl - Daemons???
- nn_nets2.rpl - More network functions
- nn_nfp.rpl - Nintendo Network Nintendo Figurine Platform (Amiibo)
- nn_nim.rpl
- nn_olv.rpl - Olive/OLV - Miiverse
- nn_pdm.rpl - System Play related data (play times etc.)
- nn_save.rpl - SAVE library
- nn_sl.rpl
- nn_spm.rpl - Storage related functions (USB?)
- nn_temp.rpl - TEMP library (for temporary files)
- nn_uds.rpl - UDS/Local Connection library
- nn_vctl.rpl
- nsysccr.rpl
- nsyshid.rpl
- nsyskbd.rpl
- nsysnet.rpl - BSD sockets
- nsysuhs.rpl
- nsysuvd.rpl
- ntag.rpl - NTAG high level NFC library
- padscore.rpl
- proc_ui.rpl
- snd_core.rpl
- snd_user.rpl
- sndcore2.rpl
- snduser2.rpl
- swkbd.rpl
- sysapp.rpl
- tcl.rpl
- tve.rpl
- uac.rpl
- uac_rpl.rpl
- usb_mic.rpl
- uvc.rpl
- uvd.rpl
- vpad.rpl
- vpadbase.rpl
- zlib125.rpl
Memory Map
- 0x01000000 - 0x01?????? Loader and system libraries
- 0x10000000 - 0x10?????? User-mode OS globals
- 0xe0000000 - 0xe4000000 Some sort of hardware communication area
- 0xf4000000 - 0xf6000000 Unknown
- 0xf6000000 - 0xf6800000 Unknown
- 0xf8000000 - 0xfb000000 Read-only shared data (system fonts mostly)
- 0xffee0000 - 0xfff20000 Kernel code