Re: Porting UNIX to AS/400

Hello Bob,

The AS/400 supports the POSIX Spec1170 APIs.  Check the UNIX API section of the 
System 
Programmer's Reference.  That almost makes it Unix and with the QSHELL you'd be 
hard pressed 
to know the difference -- Oh, yes, the 400 doesn't fall over as often :)

However, Unix is not Unix (Open Systems? Hah! It depends very much on your 
definition of 
"open") and porting between Unix systems usually involves some conversions.   
The same is true 
of the AS/400.

The AS/400 has an ANSII C compiler so you should be able to port the Unix code 
(assuming it is 
written in C).  COBOL is also straight-forward.  It will be much easier if you 
stay with the 
current HLL rather than convert the language as well as the application.

The screen handling is likely to be the most painful since I doubt the 
application use STDIN 
and STDOUT to communicate with the user.  The 400 does not provide support for 
X or curses so 
you will need to change this.  

You may also need to change the file handling.  Stream files should port 
painlessly but 
database files may have major dialectic differences.

I believe there is an AIX version of the IPCS but you'll have to beg favours 
from the right 
person to be able to get that PRPQ.

All in all it can be done and isn't that hard.  Make sure you know how much of 
the existing 
application with need to be changed.

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> X-Mailer: Worldtalk (NetJunction 4.5)/MIME
> Date: Mon, 17 May 99 17:54:24 -0500
> From: "Marion, Bob" <Bob.Marion@ps.net>
> To: "'Midrange List'" <Midrange-L@midrange.com>
> Reply-To: MIDRANGE-L@midrange.com
> Subject: Porting UNIX to AS/400

> Greetings:
> 
> I am researching for options that are available to port a unix application to 
>an AS/400;  
load the files in to the IFS and port/convert the programs via? to what 
language?.  The 
location of a white paper listing the options would be ideal along with any 
additional 
personal experiences.  Many of my apps runs on the AS/400, however this app 
does not and if 
the AS/400 could run some type of unix emulation, or run a different 
personality, or can it 
run on the IPCS card?   We would move the app over and run as is and then 
convert to the 
native 400 packages at a later time.
> 
> TIA 
> 
> 
> Bob Marion
> AS/400 Technical Support
> Phone:  972/461-3186
> Fax:  972/461-3030
> EMail:  bob.marion@ps.net

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