Re: non-ASCII environment

[Stephen Powell <zlinuxman@wowway.com>]

On Fri, 9 Apr 2010 13:18:29 -0400 (EDT), Eduardo M KALINOWSKI wrote:
> On Fri, 9 Apr 2010, Jerome BENOIT wrote:
>> Hello List,
>>
>> I am writing some C code which involves ASCII characters:
>> in C related books, we can find a lot of comments about
>> ASCII character issues, as far as we are concern with portability.
>>
>> Nevertheless, something bothers me: where non-ASCII environment can  
>> be found ?
>>
>> Furthermore, can such an environment be created on a Debian box ?
>> The aim is to check the portability of my code.
> 
> There are still IBM Mainframes around that use EBCDIC (yes, that is  
> not just an IT legend). I don't know if they can run a UNIX-like OS  
> and if you can compile your C code to run on it, but even if you  
> could, I'm not sure someone in possession of such mainframe will lend  
> it for you to run your tests. :-)
> 
> IBM Mainframes apart, I don't think any machine that you should  
> actually care for is non-ASCII.

Eduardo is correct.  IBM mainframes do use EBCDIC.  They always have.
They always will.  (Changing to ASCII now would break EVERYTHING.)
I am a systems programmer for IBM mainframes, and have been for the
last umpteen years; so I speak from personal experience.  And yes,
modern mainframe operating systems do have a POSIX interface.
z/OS (MVS) calls it "Unix System Services".  z/VM calls it
"OpenExtensions".  It is a Unix-like interface, but it uses EBCDIC
internally.

You can also run GNU/Linux on a mainframe, either directly in an LPAR
or in a virtual machine under z/VM.  But GNU/Linux is an ASCII-based
operating system, even when running on a mainframe.  Linux device
drivers for the s390 architecture talk EBCDIC when necessary to
communicate with EBCDIC devices (such as I/O to the 3215 virtual console
under z/VM or reading the disk labels of OS- or CMS-formatted disks),
but as observed by an application program running under Linux on
the s390 architecture, it is running in a pure ASCII environment.

-- 
  .''`.     Stephen Powell    <zlinuxman@wowway.com>
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