[Info-vax] An alternative history of computing

[Arne Vajhøj]

On 7/24/2021 10:43 AM, Simon Clubley wrote:
> On 2021-07-24, Andrew Commons <andrew.commons at bigpond.com> wrote:
>> On Friday, 23 July 2021 at 3:22:30 am UTC+9:30, Simon Clubley wrote:
>>> DECnet is not an open specification.
>>>
>>> Parts of it are fully open (the lower-level NSP and related stuff) but
>>> most of the higher-level application protocols are fully closed.
>>>
>> So, DECnet is/was an open specification.
>>
>> Some of it can be found here:
>>
>> ftp://bitsavers.informatik.uni-stuttgart.de/pdf/dec/decnet/
>>
>> The fact that the layered applications were not open does not change the
>> validity of that statement.
> 
> Unfortunately, a protocol which only opens its lower layers and only
> 1 or 2 of its upper layer protocols is not open in any way that could
> accurately be described as open.
> 
> It would be like saying that TCP/IP is open if only everything at TCP
> level and below was fully open along with FTP and a partial Telnet
> specification while everything else in the TCP/IP stack was fully closed.
> 
> The point of an open protocol is that you can fully implement another
> full version of it just by reading the specifications. You can do that
> with TCP/IP but you most certainly cannot do that with the subset of
> DECnet specifications that are available.
> 
> Not even the MAIL protocol is documented in public. That would be like
> calling TCP/IP open while keeping the SMTP specification closed.

A protocol is open if it itself is documented.

Other protocols on top of it can be open or closed without
impacting that.

There are also closed protocols on top of TCP/IP - that
does not make TCP/IP closed.

Arne