I'll plead ignorance of mainframe OS historical idiosyncrasies.

(but observe IBM's aggressively making progress on hosting linux on 390's)

> From: "Bradd W. Szonye" <xxxxxx@szonye.com>
> Date: Fri, 13 Feb 2004 19:04:01 -0800
> To: xxxxxx@srfi.schemers.org
> Subject: Re: Encodings.
> Resent-From: xxxxxx@srfi.schemers.org
> Resent-Date: Sat, 14 Feb 2004 04:04:11 +0100 (NFT)
>
> On Fri, Feb 13, 2004 at 09:19:21PM -0500, Paul Schlie wrote:
>> From the best I can tell, there is no difference between opening a
>> file using C's fopen function in binary mode or text mode, with the
>> exception Of local conversion of new-line marker character(s) in VMS,
>> MS-whatever, UNIX, MAC, etc.; both can be read/written logically
>> sequentially ....
>
> Yes, the "text is filtered binary stream" abstraction is very common.
> But it is not universal. It is not true on MVS, for example. (When I
> wrote "VMS" earlier, it was a typo for "MVS.") Indeed, it's partly
> because of systems like MVS that C makes the distinction between text
> and binary mode. If you insist on forcing that abstraction into Scheme
> standards, then you make it impossible to sensibly implement Scheme on
> many mainframe computers and anything else where that abstraction is
> invalid.
> --
> Bradd W. Szonye
> http://www.szonye.com/bradd
>