A dirty Bit is computer lingo. When the "bit" tells the computers OS or operating system that it is about to write new data to a disk. Once the new data is being added the "dirty bit" is usually removed. a single 'bit" of memory.
A guy you probably have worked with that will sleep with anything propped up on two legs with an ass (preferably when she is really really drunk). Usually will consider himself a pimp and wear Cadillac hood ornaments and have huge stupid sideburns. His fingers smell of a whore’s ass and his flat is usually decorated with stupid shit like bullhorns and other phallic trash.