{"id":182,"date":"2008-05-25T22:59:26","date_gmt":"2008-05-25T22:59:26","guid":{"rendered":"http:\/\/www.reactivated.net\/weblog\/?p=182"},"modified":"2008-05-25T23:37:01","modified_gmt":"2008-05-25T23:37:01","slug":"libusb-10-enters-beta","status":"publish","type":"post","link":"https:\/\/www.reactivated.net\/weblog\/archives\/2008\/05\/libusb-10-enters-beta\/","title":{"rendered":"libusb-1.0 enters beta"},"content":{"rendered":"

I’ve been making good progress on libusb-1.0<\/a>, which has now entered beta. Features over libusb-0.1 include:<\/p>\n

    \n
  1. Asynchronous transfer capabilities (in addition to the synchronous style presented by v0.1)<\/li>\n
  2. Support for transfers to isochronous endpoints<\/li>\n
  3. Significantly faster bulk transfer performance for large transfers (several kilobytes or more)<\/li>\n
  4. Detailed API documentation<\/a><\/li>\n
  5. Power saving: on systems running recent Linux kernels, libusb-1.0 does not wake up all the USB devices plugged into the system during device enumeration<\/li>\n
  6. Greatly reduced CPU usage while waiting for results of bulk\/interrupt transfers (libusb-0.1 was waking up every 1ms)<\/li>\n
  7. Thread safety<\/li>\n<\/ol>\n

    Backwards compatibility<\/b><\/p>\n

    As noted on the homepage, libusb-1.0 is entirely incompatible with libusb-0.1. However, it is designed to install in parallel, in the same way that you can have GTK+ 1.2 and GTK+ 2.x installed on the same system and in use at the same time.<\/p>\n

    I have also produced a compatibility layer which replaces libusb-0.1. libusb-compat-0.1<\/b> looks and smells exactly the same as libusb-0.1 (same library name, API, header file, etc) but internally it just converts libusb-0.1 calls to libusb-1.0.<\/p>\n

    This means that existing libusb-0.1 applications can take advantage of some of the new libusb-1.0 hotness mentioned above: improved bulk I\/O performance, decreased CPU usage, power saving. These improvements appear without any modification<\/em> to the original application, provided that the user has uninstalled libusb-0.1, and installed libusb-1.0 plus libusb-compat-0.1.<\/p>\n

    Status<\/b><\/p>\n

    I’m hoping this release will result in:<\/p>\n