According to Nintendo, "WiiConnect24 allows the console to receive downloads even when the console isn't in active use, as long as it has a working connection to the Internet." However, this is an incomplete description, as it fails to explain why there exists a configuration option to enable WC24, but disable "Standby Connect".
WC24 is actually a codename for the /dev/kd driver in IOS that allows the Starlet core to perform network-related tasks when the main CPU (Broadway) is powered off. Only a small fractional of the full functionality of this software is being used -- generally to either download large chunks of data in the background (system updates?) or keep small amounts of data continuously updated (news, weather, friend data in games, etc.)
The kd driver is large -- about 360k -- and makes heavy use of the SSL, SO (socket) and WL / ETH (wireless / Ethernet) drivers; together, this functionality comprises about 75% of the firmware.
Static analysis reveals the following main categories of functionality:
- Sophisticated task scheduler, including periodic wakeup of either processor for maintenance tasks, and tracking max duty cycle ("Too much wakeup executed recently. Need to wait."), probably used for thermal management
- SMTP engine, for sending and receiving email
- Real-time clock, with synchronization to a Nintendo-run server (over SSL)
- Logging / debug capability, e.g.
13DFA93C DCB "This report was sent from Wii to debug your scripts.",0xD,0xA 13DFA93C ; DATA XREF: NWC24WriteLogFile:off_13DB619C�o 13DFA93C DCB "The result summary is in the following:",0xD,0xA 13DFA93C DCB 0xD,0xA 13DFA93C DCB "- General information",0xD,0xA 13DFA93C DCB " WiiConnect24 result code : %d",0xD,0xA 13DFA93C DCB " Number of committed mail : %d",0xD,0xA 13DFA93C DCB " VF archive : %s",0xD,0xA 13DFA93C DCB 0xD,0xA 13DFA93C DCB "- Trigger mail information",0xD,0xA 13DFA93C DCB " Application ID : 0x%08x [%c%c%c%c]",0xD,0xA 13DFA93C DCB " Group ID : 0x%04x [%c%c]",0xD,0xA 13DFA93C DCB " Script parameter : 0x%02x",0xD,0xA 13DFA93C DCB " Time to live : %d",0xD,0xA 13DFA93C DCB " Number of attached file : %d",0xD,0xA 13DFA93C DCB 0xD,0xA 13DFA93C DCB "- Virtual machine specific information",0xD,0xA 13DFA93C DCB " Result code of the VM : %d [%s]",0xD,0xA 13DFA93C DCB " Return value of the script : 0x%016llx",0xD,0xA 13DFA93C DCB " Last PC : 0x%08x",0xD,0xA 13DFA93C DCB " Last line : %u",0xD,0xA 13DFA93C DCB " Initial free work size : %u",0xD,0xA 13DFA93C DCB " Minimum free work size : %u",0xD,0xA 13DFA93C DCB 0xD,0xA 13DFA93C DCB "For more information, please see the attached log file.",0xD,0xA
- Friend list management
The message board is a place where you can send and receive messages with other Wiis and email addresses. Games can also put messages here for accomplishments and the like. Channels can also send you updates and Nintendo can alert you when your firmware is ready to be updated. This is handled using SMTP.
See Friend Codes
Wii games using WC24:
- Big Brain Academy: Wii Degree
- Dewy's Adventure
- Jissen Pachi-Slot Pachinko Hisshôhô! Hokuto no Ken Wii
- Mario Kart Wii
- Metroid Prime 3: Corruption
- Pro Evolution Soccer 2008
- Super Smash Bros. Brawl
WiiWare games using WC24:
- Dr. Mario Online Rx
- Everyone's Pokémon Ranch
See Friend Codes
Channels using WC24:
- Forecast Channel
- News Channel
- Nintendo Channel
- Everybody Votes Channel
- Check Mii Out Channel
- Mario Kart Wii Channel
- Mii Channel
- Wii Shop Channel