Re: Linux Kernel constraints!

Justin Bradford (justin@ukans.edu)
Thu, 21 Jan 1999 17:16:54 -0600 (CST)


> Recently(dec.) in WindowsNT magazine comparisons/similarities between
> various flavours of unix and nt had come. In the same article Linux was
> ignored as enterprise os on account of following kernel 'limitations' :

Windows NT magazine also ran an article stating all Linux programs had to
distribute their source. In the same article, they mention Oracle,
Informix, and Corel porting. So where do I download Oracle 8 source?!?
The Win NT writers either aren't bright enough to understand the LGPL,
or they're deliberately spreading misinformation.
Either way, I can't imagine any group of people less qualified to comment
on the Linux kernel.

> 1. kernel is not preemptive. ie even a higher priority user thread cant
> cause another thread to be swapped if the other thread is presently running
> in privileged/kernel context.
> 2. kernel is not reentrant. ie.only one thread in kernel context at a time.

I believe these complaints may apply to the 2.0 kernel, due to kernel wide
spin-locks, but not 2.2

> 3. kernel is not multi processing in the sense that on multiprocessor
> systems it will run on only one cpu at a time.

This I don't believe. What would be the point of SMP support if it only
used one processor at a time? So either they're looking at a kernel prior
to SMP, or they have no idea what they're talking about. Or possibly, I've
misunderstood the statement.

> will somebody can clarify these doubts and version which enabled it to be
> otherwise.

I'm by no means a kernel expert, but I didn't see any other responses.
Anyway, I might be wrong.

Justin Bradford
justin@ukans.edu

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