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Re: 32 bits time_t and Y2038 issue

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On 19/03/2025 23:09, Waldek Hebisch wrote:
> David Brown <david.brown@hesbynett.no> wrote:
>> On 19/03/2025 15:27, Grant Edwards wrote:
>>> On 2025-03-19, David Brown <david.brown@hesbynett.no> wrote:
>>>
>>>> There are certainly a few things that Cygwin can handle that msys2
>>>> cannot.  For example, cygwin provides the "fork" system call that is
>>>> very slow and expensive on Windows, but fundamental to old *nix
>>>> software.
>>>
>>> I believe Windows inherited that from VAX/VMS via Dave Cutler.
>>
>> I am always a bit wary of people saying features were copied from VMS
>> into Windows NT, simply because the same person was a major part of the
>> development.  Windows NT was the descendent of DOS-based Windows, which
>> in turn was the descendent of DOS.  These previous systems had nothing
>> remotely like "fork", but Windows already had multi-threading.  When you
>> have decent thread support, the use of "fork" is much lower - equally,
>> in the *nix world at the time, the use-case for threading was much lower
>> because they had good "fork" support.  Thus Windows NT did not get
>> "fork" because it was not worth the effort - making existing thread
>> support better was a lot more important.
> 
> Actually, Microsoft folks say that Windows NT kernel supports fork.
> It was used to implement Posix subsystem.  IIUC they claim that
> trouble is in upper layers: much of Windows API is _not_ kernel
> and implementing well behaving fork means that all layers below
> user program, starting from kernel would have to implement
> fork.
> 
> So this complicated layered structure seem to be main technical
> reason of not having fork at API level.  And this structure
> is like VMS and Mica.  Part of this layering could be motivated
> by early Windows split between DOS and Windows proper, but
> as Grant explained, VMS influence was stronger.
> 
> IIUC early NT developement was part of joint IBM-Microsoft
> effort to create OS/2, so clearly DOS and Windows influence
> were limited.  Only later Microsoft decided to merge
> classic Windows and NT and effectively abandon other
> system iterfaces than Windows API.
> 

DOS and Windows were a relevant part of OS/2 development too.  Both IBM 
and MS were fully aware that if OS/2 and/or NT were to succeed, 
compatibility with existing software was essential.  But more than that, 
compatibility with existing software /developers/ was essential.

But you are absolutely right that the NT kernel was originally intended 
to support different API's or "personalities" (I think that was the term 
used) - at least WinAPI, OS/2 and POSIX.  It was also the intention that 
the OS/2 kernel would be similarly flexible, so that users could pick 
their base system and run all sorts of different software on top.  IBM 
and MS worked together for interoperability.  Having at least minimal 
support for "fork" would have been necessary (along with things like 
case-sensitive filename support).

However, it did not take long for MS to realise that they could stab IBM 
in the back and take everything for themselves - through a mixture of 
technical, economic, legal and illegal shenanigans, they killed off OS/2 
as an OS and as an API, and dropped everything but the WinAPI interface. 
  (As you point out, much of that was at a higher level than the kernel 
itself.)


There's a lot of interesting detail here from you and Grant, which I 
appreciate.  However, we've strayed a long way from the OP's original 
question and topic, and it's not really about embedded systems any more. 
  I hope Pozz got what he needed before we drifted!

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32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-11 16:22 +0100
  Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-11 17:32 +0100
    Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-11 23:21 +0100
      Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-12 10:33 +0100
        Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-12 16:48 +0100
          Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-12 17:39 +0100
            Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-12 18:13 +0100
              Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-12 19:18 +0100
                Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-13 09:57 +0100
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-13 16:51 +0100
                Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-14 13:27 +0100
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-14 14:20 +0100
    Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-12 08:44 +0100
      Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-12 11:14 +0100
      Re: 32 bits time_t and Y2038 issue antispam@fricas.org (Waldek Hebisch) - 2025-03-14 01:48 +0000
        Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-14 08:36 +0100
    Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-15 16:30 +0000
      Re: 32 bits time_t and Y2038 issue Grant Edwards <invalid@invalid.invalid> - 2025-03-15 17:02 +0000
        Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-15 23:26 +0000
      Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-18 09:21 +0100
        Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-18 11:34 +0100
          Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-18 17:31 +0100
            Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-18 20:29 +0100
              Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-21 09:20 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-21 13:54 +0100
                Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-21 20:53 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-22 11:19 +0100
                Re: 32 bits time_t and Y2038 issue antispam@fricas.org (Waldek Hebisch) - 2025-03-21 14:35 +0000
          Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-18 18:28 +0000
            Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-18 20:43 +0100
              Re: 32 bits time_t and Y2038 issue Grant Edwards <invalid@invalid.invalid> - 2025-03-18 20:58 +0000
                Re: 32 bits time_t and Y2038 issue Hans-Bernhard Bröker <HBBroeker@gmail.com> - 2025-03-18 23:31 +0100
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-19 11:24 +0100
                Re: 32 bits time_t and Y2038 issue Grant Edwards <invalid@invalid.invalid> - 2025-03-19 14:27 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-19 17:33 +0100
                Re: 32 bits time_t and Y2038 issue Grant Edwards <invalid@invalid.invalid> - 2025-03-19 19:08 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-19 21:14 +0100
                Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-21 09:48 +0000
                Re: 32 bits time_t and Y2038 issue Grant Edwards <invalid@invalid.invalid> - 2025-03-21 13:27 +0000
                Re: 32 bits time_t and Y2038 issue antispam@fricas.org (Waldek Hebisch) - 2025-03-19 22:09 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-20 09:26 +0100
                Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-21 22:40 +0100
                Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-21 09:23 +0000
                Re: 32 bits time_t and Y2038 issue Hans-Bernhard Bröker <HBBroeker@gmail.com> - 2025-03-21 22:38 +0100
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-19 08:24 +0100
              Re: 32 bits time_t and Y2038 issue antispam@fricas.org (Waldek Hebisch) - 2025-03-21 14:04 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-21 16:45 +0100
                Re: 32 bits time_t and Y2038 issue pozz <pozzugno@gmail.com> - 2025-03-21 22:51 +0100
                Re: 32 bits time_t and Y2038 issue Hans-Bernhard Bröker <HBBroeker@gmail.com> - 2025-03-22 00:00 +0100
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-22 14:29 +0100
                Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-22 14:46 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-22 17:57 +0100
                Re: 32 bits time_t and Y2038 issue antispam@fricas.org (Waldek Hebisch) - 2025-03-22 15:57 +0000
                Re: 32 bits time_t and Y2038 issue David Brown <david.brown@hesbynett.no> - 2025-03-22 18:02 +0100
        Re: 32 bits time_t and Y2038 issue Michael Schwingen <news-1513678000@discworld.dascon.de> - 2025-03-18 18:44 +0000

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