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i586 kernel support for Pentium MMX and AMD K6-2 processors

Posted: Wed May 18, 2016 7:45 pm
by jimmychonga1028
Will ReactOS eventually support older i586 processors like the Pentium MMX and AMD K6-2? The current kernel causes a reboot from the Pentium's/K6's missing i686 assembly instruction "CMOV".

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Thu May 19, 2016 12:47 am
by karlexceed
Since the current compatability target is Server 2003, if your hardware can run that, it should run ROS. Anything beyond that is not guaranteed...

From: https://technet.microsoft.com/en-us/lib ... s.10).aspx
Windows Server 2003, Standard Edition: System requirements
To ensure adequate performance, make sure that computers on which you install or upgrade to Windows Server 2003, Standard Edition meet the following requirements:

For an x86-based computer:
One or more processors with a recommended minimum speed of 550 megahertz (MHz). The minimum supported speed is 133 MHz. A maximum of four processors per computer is supported. Processors from the Intel Pentium/Celeron family, AMD K6/Athlon/Duron family, or compatible processors are recommended.
256 megabytes (MB) of RAM (recommended minimum). 128 MB is the minimum supported, and 4 gigabytes (GB) is the maximum supported.

For an x64-based computer:
One or more processors with a minimum speed of 1.4 gigahertz (GHz). A maximum of four processors per computer is supported.
512 MB of RAM (minimum).

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Thu May 19, 2016 12:51 pm
by middings
This page https://www.reactos.org/wiki/ReactOS_ports describes the CPU architectures toward which the developer team put their primary attention.

Hint: x86 and x64.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Thu May 19, 2016 8:31 pm
by jimmychonga1028
I can run Windows Server 2003 on an AMD K6-2 with 512MB RAM with no problems. But ReactOS causes an instant reboot when the CD boots. Are you implying that ReactOS ripped off Microsoft's kernel binaries byte-for-byte? If not then your compiler for ReactOS probably introduced some i686 assembly instructions not supported by the K6-2.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Fri May 20, 2016 7:07 am
by Black_Fox
Yeah, it seems your question was misunderstood by the guys. I think that CMOV-supporting CPUs will be the minimum also for the future, but we need a developer to confirm. If you need a quicker answer, I recommend visiting IRC, that's where the developers are. Only a part of them come to the forums.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Fri May 20, 2016 12:16 pm
by erkinalp
. I think that CMOV-supporting CPUs will be the minimum also for the future,
However, there may be unofficial ports to older CPUs like Debian ports.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Fri May 20, 2016 7:18 pm
by jimmychonga1028
An unofficial port for older CPUs would be wonderful. I look forward to testing it out on a bootable CD. 8-)

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Fri May 20, 2016 11:21 pm
by middings
Pentium MMX turns 20 years old in January of next year. Machines with that processor were typically shipped with Microsoft Windows 95 and Microsoft Windows 98. The Pentium 4 turned 15 years old late last year. Most Pentium 4 machines were shipped with Microsoft Windows XP. ReactOS will work best on machines that were built to support Microsoft Windows XP and Microsoft Server 2003.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Mon May 23, 2016 11:30 pm
by Z98
I'm pretty sure internally a decision was made to support only i686 and later to make the lives of the people maintaining the build system simpler.

Re: i586 kernel support for Pentium MMX and AMD K6-2 process

Posted: Tue May 24, 2016 12:48 am
by Konata
Supporting old, outdated hardware that's not even common anymore is a bit insane, especially when ReactOS would probably just barely run on them, and not even taking drivers for said machines into account, which are probably all VxD and not WDM, and I'm not even sure if NT4 and below drivers work in ReactOS or ever will. If someone wants to make some kind of fork to support DOS-era machines with some things removed and special modifications, that would be pretty cool. But I think it would be silly to put such support in the mainstream build, especially when it would run like garbage.

This reminds me of how much I'd love an open-source Windows 9x, though. Until then, we have FreeDOS and Cobalt.