[VxW] Re: Common address space

[suresh nayak]

I would like to add on what Joe said...

POSIX standard wants that all the processes should have protection....it
means that process A cant do anything which belongs to process B,
directly. VxWorks doesn’t really behaves like POSIX and believes that
taking care of address space is programmers botheration and not of OS.

Its because of this startegy that the VxWorks is able to achieve
benchmarks. But even VxWorks developers know that there startegy wont
work in some cases, so they have come up with memory protection which is
a scalable component of vxWorks OS and its not FREE.


Thanks and Regards,

Suresh Nayak
Research Engineer
Are Technologies Ltd.
Email: suresh.nayak at aretechnologies.net
Tel: +91 22 2857 6222 Fax: +91 22 2857 2635
Address: #406-B, Oxford Chambers, Saki Vihar Road, Andheri (East),
Mumbai - 400072, India
 
Please visit http://www.aretechnologies.net; http://www.acewp.com  for
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-----Original Message-----
From: vxwexplo-bounces at csg.lbl.gov [mailto:vxwexplo-bounces at csg.lbl.gov]
On Behalf Of arvind M
Sent: Monday, March 08, 2004 11:51 AM
To: vxwexplo at csg.lbl.gov
Subject: [VxW] Re: Common address space


> 
> 	I don't know about calling it an advantage, but the basic
difference 
> is that with a common address space, all globals are _really_ global.

> vxWorks tasks are in effect, threads.  If you didn't have this 
> feature, you could make tasks into processes, which do not share 
> visibility of infomration between themselves.
> 
> An effect is that task A can write into things that task B is supposed

> to be worrying about (accidentally or deilberately), and vice versa.
> 
> Speaking only for myself,
> 
> Joe Durusau

Thanks joe,
          But if the user task  tries to write anything onto the kernel
space wont a exception will be raised.I am talking about vxworks5.4.Also
when we delete a task or a task gets out of existance ,will it free also
free up the memory space which was occupied by it.

Thanks and regards,
Arvind M

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