Subject: Help with Real-time Support
To: None <>
From: liu deng <>
List: tech-kern
Date: 05/11/2006 20:53:38
Hi, all:

I'm looking for some help with Real-time Support. It is very pity that
the most portable Operating System, NetBSD, does not suitable for the
real time applications. Furthermore, even the soft Real-time support
is absent from this OS compared with modern Linux.

There, I'm going to add Real-time support on the NetBSD kernel.
Although I had read some papers about those topics which introduce how
to add Real-time function on the General-Purposed OS such as Linux, I
can't find the entrance where to merge the function into NetBSD

The design issues come as follow:

1: Hard- or Soft- Real-time. Does NetBSD intend to play with hard
Real-time applications?

2: native Real-time kernel, I wish, could use the GPOS's facilities
such as APIs rather than double kernels like RT-Linux.

3: preemptable kernel. preemptable points or fully preemptable? The
Monta Vista Software Inc. had released the preemptable Linux kernel
patch for a long time. It claimed that the patch was just 1000 lines
in length in Linux2.4 kernel and did four basic changes.(preemptable
Spinlock, modified interrupt handling software,  changed Spin unlock,
and the kernel build options). Also, It said that the FreeBSD project
intend to transform the FreeBSD kernel into a fully preemptable
kernel. Unfortunately, beside some SMP related ones, I can't find any
documents describe the preemptable translation on FreeBSD website.
Anybody please send me the URL if you know that.

4: fine-grained timer. Obviously, it is important, but straightforward.

5: interrupt control. Many research products adopted a soft interrupt
emulator invented by RT-Linux. Should we?

6: framework. Frameworks introduced by RED-Linux and 'Open
Environment' are both excellent, can we integrate one of the two into

I am a postgraduate student, and I prepare about 4 - 6 months or more
to achieve this task.

any advices are appreciated.