benefits of user space
Posted Sep 8, 2006 3:11 UTC (Fri) by pjm
In reply to: Support for drivers in user space
Parent article: Support for drivers in user space
Indeed: I'd have thought that one of the primary reasons for userspace drivers is for the greater fault isolation. Many device drivers have noticeably lower quality code and tend to have more bugs per line of code than the rest of the kernel. Moving to userspace (separate address space, more familiar programming environment) reduces the harm that can be done: buggy userspace device drivers can still bring down the system, but there's less opportunity for bugs to silently corrupt unrelated parts of memory (for example).
(Device drivers tend to be written by people with knowledge of / access to the device in question, and are often not regular kernel developers. The limited pool of people with access to a particular device means that fewer eyes pass over the code, and in particular that fewer exceptionally good programmers look at the code as some of the rest of Linux.)
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