On Wed, 13 Feb 2008, Derek Smithies wrote:
Linux is a monolithic kernel + modules - it is not a micro kernel. John's original subject line says it quite nicely "of not quite monolithic kernel" However, he then went on to talk about micro kernels and linux. Which is misleading...
The reason for the mention of Microkernels was... One of the much trumpeted benefits of microkernels were that drivers were "Just Another Userland Process". As such, if a driver goes mad, the bad madness is constrained to only that process. And the driver can be restarted without restarting the whole kernel. My posts highlights a case where... * A driver had gone Mad and Bad. * The Madness and Badness had, without the strong protection of a hardware mmu, been constrained to only that driver. (The system is still up and working and I'm typing this on it.) * The driver had been "restarted", even though it can't be thought to exist in a "process". ie. One of the prime claimed benefits of a microkernel, had, in one instance, been achieved in practice in a "not quite monolithic" one. The other coolness factor of the whole event was that _only_ the removal of the module by the superuser was required. Udev had automagically and instantly seen to the reinsertion. John Carter Phone : (64)(3) 358 6639 Tait Electronics Fax : (64)(3) 359 4632 PO Box 1645 Christchurch Email : [EMAIL PROTECTED] New Zealand
