[Info-vax] misstatement of Unix origin [was Re: A portable VMS, was: Re: OS Ancestry]

[Arne Vajhøj]

On 5/24/2021 8:01 PM, chris wrote:
> On 05/25/21 00:58, Dave Froble wrote:
>> On 5/24/2021 2:05 PM, Simon Clubley wrote:
>>> On 2021-05-24, John Wallace <johnwallace4 at yahoo.co.uk> wrote:
>>>> On 24/05/2021 13:28, Simon Clubley wrote:
>>>>> Yes, oops. :-) Somebody already reminded me about this a few days ago
>>>>> and as I pointed out in response this just shows how much more 
>>>>> portable
>>>>> things are when you are using an implemention language not tied to the
>>>>> architecture.
>>>>>
>>>>
>>>> Yeah sure, UNIX code was so portable that back in the 1980s anything
>>>> much more complex than "Hello World" had little chance of being 
>>>> portable
>>>> between (e.g.) BSD and System V even on the very same hardware.
>>>>
>>>> When the two main camps can't even agree on the basics of opening a 
>>>> file
>>>> from C,
>>>> as in fd = open(...),
>>>> it's no wonder there was a customer/vendor need for a Single UNIX
>>>> Specification.
>>>>
>>>> Fortunately times have moved on since then.
>>>
>>> You are confusing functionality of an operating system with the
>>> portability of an operating system between architectures.
>>>
>>> Your comments above talk about functionality within an operating
>>> system. I am talking about the ease of porting an operating system
>>> from one architecture to another.
>>>
>>> The choice of implementation language does not decide the functionality
>>> of an operating system. It is however a major factor in how easy or not
>>> it is to port that operating system to another architecture.
>>
>> Even when (hawk, spit, gag) C doesn't work the same on different
>> architectures?
> 
> No problem if you write portable code and don't rely on invisible
> underlying architecture or OS differences. Code I wrote decades ago
> is still usable now...

It is certainly possible to write portable C code.

But it is not trivial to write portable C code. Usage
of implementation specific behavior, assumptions
about various sizes etc..

Arne