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O'Reilly Network: Linux Device Drivers Update

Jun 10, 2001, 22:29 (0 Talkback[s])
(Other stories by Allen Noren, Derrick Story)

LWN's Jonathan Corbet sits down for a quick interview regarding the state of Linux device driver support and a look at what's ahead.

"Perhaps the biggest change, one that will affect every driver author, is the incorporation of fine-grained locking in the kernel. In 2.0, everything was protected by the "big kernel lock," and device drivers had no need to deal with concurrency on SMP systems. Version 2.2 had split that up somewhat, but it's only in 2.4 that locking has, in many cases, been pushed down into the driver level itself. Any device driver that is not written with SMP in mind is not correct in 2.4.

Beyond that, there have been numerous changes to many kernel subsystems. Bottom halves have been replaced with tasklets, the scheduler queue has been replaced with a new event-scheduling mechanism, and the block and network driver interfaces have been substantially changed. The number of platforms supported has increased significantly, as has the number of devices. Many things have been cleaned up; the 2.4 driver interface is much nicer to work with than earlier versions."

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