sentence: at the same time , there are several projects which are experimenting with tpm support in free operating systems ; examples of such projects include a tpm device driver for linux , an open source implementation of the tcg 's trusted software stack called trousers ( also ported to windows vista and windows 7 in 2010 ) , a java interface to tpm capabilities called tpm/j , and a tpm-supporting version of the grub bootloader called trustedgrub .