Let's not forget X11 which has a long history as well starting in
1984. The 11th version of the protocol (X11) dates from 1987. All the
X11 versions are online still due to the X consortium. However, X10
and earlier can be hard to find. https://www.x.org/releases/ has X10R3
and X10R4, but nothing earlier. That's also a huge part of Linux since
it represents its windowing system. I used X10 on a sun 3/50 back in
the day before they upgraded it to X11. It was slower and buggier than
SunTools, but more cutting edge. suntools is dead and X11 is still
alive. suntools went directly to the frame buffer, while X always did
the protocol thing (though with many attempts over the years to make
the protocol layer optional, maybe wayland will finally succeed)...

Many of the gnu tools started life as BSD code that was hacked on and
rebranded with the GPL. Most of that original code is now gone, but in
the early days it was the source of much friction between the BSD and
GPL communities, even if a lot (all) of the code was eventually
replaced... It wasn't so much the use of the code that bothered
people, but the filing off of the original attributions...  All that's
water under the bridge, but the fact that this happened, as well as
many other incidents in the early days, goes a long way to explain
many of the hard feelings and out-sized reactions you used to see back
in the day.... This is also an important motivating factor for the
foundation that Linux was built on: This friction, the causes of which
were partially real or and partially imagined, drive much innovation
in both camps...

Warner

On Tue, Mar 14, 2017 at 10:20 AM, Arthur Krewat <krewat at kilonet.net> wrote:
> Everything. I'm trying to grok how long Linux as a whole was in active
> development. That includes all the GNU utilities, GCC, everything.
>
> Just like a "regular" corporate development environment would have devoted
> to the cause :)
>
>
>
>
> On 3/14/2017 11:57 AM, Michael Kjörling wrote:
>>
>> On 14 Mar 2017 11:51 -0400, from krewat at kilonet.net (Arthur Krewat):
>>>
>>> in reality, how much of Linux was based on previous works?
>>
>> Linux the kernel, or Linux the usable operating system (which would
>> include at least the essential userspace parts)?
>>
>