Re: Is an RTOS Required for Ada?

[Rakesh Malhotra <rakesh.malhotra@pop.safetran.com>]

Tramse wrote:
> 
> I have an application in which Ada95 is required.  The target microcontroller
> is the Motorola 68336.  It a real simple application, it only needs to
> read/write to fixed addresses (ports/data) and respond to a interupts.  We have
> a real fast boot up requirement and small RAM resource (7.5K) and can't afford
> the boot time and RAM requried for a RTOS.
> 
Yes you can certainly use Ada.  I have done so several times by
targetting the 68302, 68332, 68030 etc.

Regarding your point that you cannot afford the extra RAM required by an
RTOS or startup time - that is dependent on the compiler you use and
what features of Ada you want to use. 

e.g. On one project I worked on we used the Alsys (Ada83, company is now
called Aonix) compiler and a kernel called the SMART kernel.  If memory
serves me, the runtime portion (kernel + library) was only about 2KB or
2.5KB.   Everything on top of that was my application.   However, SMART
imposes many restrictions e.g. you cannot do tasking.  There are other
features of Ada that SMART will not allow you to have.    Also the
startup time is very fast - in msecs.
Alsys also comes with a full kernel but then that is a lot bigger and
also has higher latencies.

There are other Ada compilers also that have a no-RTOS option or minimal
RTOS option.  If your compiler has this then you are ok.   I think there
is a version of GNAT called GNORT - GNAT with no run-time.  I have also
used the Rational Verdix cross-compiler that had similar options.


> Can we use Ada and compile direct to 68K code without using an RTOS (like we
> could in C)?

Yes.

Rakesh