ReactOS and older computers...

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nute
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ReactOS and older computers...

Post by nute » Fri Apr 10, 2009 3:29 am

I know that the goal of the ReactOS project is
the Windows NT architecture and that makes
sense. Trouble is, ReactOS requires at least
a Pentium II with at least 128 megs of ram to
run comfortably, if I am not mistaken.

Why does ReactOS need that much processing
power and RAM? Second, what about the little
ol 486 DX2-66 with 32 megs of ram running
freedos?

I recently got Windows 3.1 to run on top of freedos,
but it was no picnic and I seemingly had to make
freedos fairly unstable to do it.

I wish someone would make a clone of Windows 3.1,
call it Windows lite, that will work on 286s on up.

One of the reasons Windows 3.1 runs on old computers,
where ReactOS doesn't, is that the graphics requirements
of Windows 3.1 are very low.

Two downsides to running Windows 3.x on freedos:

1) It belongs to Microsoft still and it is not supported.

2) Freedos doesn't interact well with it.

My mouse, a logitech 3 button serial mouse, is on com4
where Windows 3.1 doesn't seem to have any drivers for
com4.

I realize that there have been discussions before about
cloning dos based Windows that have been rejected on
here, but what if someone could improve
freedos/Windows 3.x integration and release a service
pack that takes care of date and possibly other
problems in Windows 3.1?

Z98
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Re: ReactOS and older computers...

Post by Z98 » Fri Apr 10, 2009 5:17 am

The memory requirement has gone down considerably after Alex's fixes. As for processor, quite frankly, at a certain point a processor is at its end of life. A 486 definitely fits that category, considering it's nearly two decades old. We require a Pentium class processor as a minimum because we need certain instructions that were introduced with it. I mean, what use is a processor that old besides some kind of embedded system? And there are OSes designed for embedded systems, but they were designed to work with these limitations and the functionality they provide reflects that.

Anything involving an actual DOS operating system or extending it or supporting it is outside the purview of this project and we're not really interested in doing it.

nute
Posts: 251
Joined: Tue Aug 29, 2006 1:30 am

Re: ReactOS and older computers...

Post by nute » Fri Apr 10, 2009 6:53 am

It will be years at the rate that ReactOS is developing before there is a Windows
compatible alternative OS for Pentium and newer computers. Why do you need
the processing power of a Pentium for ReactOS anyways? What instructions
provided by the Pentium do you really need for ReactOS that a 486 with a math
coprocessor does not have?

Z89, you didn't answer the why on earth does ReactOS need so much processing
power question.

You also didn't talk about which Pentium instructions ReactOS needs.

Didn't NT 3.51 run on the 486?

You know what programming for an older computer might do, it might
improve the code because the resources are tighter.

Why is a community trying to clone Windows NT not interested in making it
fast enough to run on older computers with limited resources?

ReactOS would be more valuable if it could run on older pre Pentium machines.

In 1996 when this project started, 486s were still commonly used. Granted, by
that time the Pentium had come out.

Believe it or not, the Pentium is about as old as this project.

Haos
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Re: ReactOS and older computers...

Post by Haos » Fri Apr 10, 2009 10:27 am

Yawn... you can run XP on P1 133 with 32 mb RAM.

Win 3.11 is not an OS. Please do not compare it to ANY OS of NT family.

There is no real use for CPUs older than 80586...

Poor troll attempt.

Lone_Rifle
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Re: ReactOS and older computers...

Post by Lone_Rifle » Fri Apr 10, 2009 10:32 am

nute wrote: Z89, you didn't answer the why on earth does ReactOS need so much processing
power question.

You also didn't talk about which Pentium instructions ReactOS needs.
He ignored the processing power question because it is irrelevant. Tailoring any program to target a 486 as opposed to a Pentium is no longer worth the extra trouble. One should also consider that the Pentium instruction set is present in every single architecture after the Pentium itself, and writing for the 486 instruction set would just hinder the quick operation of the OS on these systems, due to absence of said Pentium instructions. Do you actually know anything about computer architectures?

The specific Pentium instructions needed can be found by disassembling the binary and referring to the relevant Intel manuals. We compile with the Pentium instruction set by default, so if you must, you could change the compiler settings when you create your own build of ROS to use the 486 instruction set.

Z98, I suggest giving him what he wants and overloading him with information, telling him the instructions present in the Pentium that are not present in the 486. At best, he'll kill himself trying to understand it due to his sheer ignorance, and we'll have one less annoying forum user to deal with.

hto
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Post by hto » Fri Apr 10, 2009 3:31 pm

nute wrote: I wish someone would make a clone of Windows 3.1, call it Windows lite, that will work on 286s on up.
http://www.reactos.org/forum/viewtopic.php?f=13&t=6735
What instructions provided by the Pentium do you really need for ReactOS that a 486 with a math coprocessor does not have?
ReactOS needs cmpxchg8b, which is only in Pentiums. Nobody volunteered to add support for 80486 since making use of this instruction. Simply compiling for i486 is not enough.

Pentium itself is already sixteen years old…

vicmarcal
Test Team
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Re: ReactOS and older computers...

Post by vicmarcal » Fri Apr 10, 2009 6:09 pm

nute wrote:I know that the goal of the ReactOS project is
the Windows NT architecture and that makes
sense. Trouble is, ReactOS requires at least
a Pentium II with at least 128 megs of ram to
run comfortably, if I am not mistaken.
This is totally False :)...
ReactOS right now is running in Pentium 1 and Pentium MMX without problem, and using 64MB RAM.
nute wrote: Why does ReactOS need that much processing
power and RAM? Second, what about the little
ol 486 DX2-66 with 32 megs of ram running
freedos?
I dont think that Pentium I and 64 Mb ram are too much power,imho. Compare them to the minimum/recommended XP hardware specifications.
BTW, testing with this "High ;) " amount of Ram and this "High ;) " power points you to a new problem: "most of the apps cant run",since they have more needs than the OS itself. Try FF 2.0 with that amount of Ram. So now ReactOS needs less hardware requirements than the apps which are running on it. This can sound indeed stupid,as too logical, but there are OS which have more needs than the apps running on it (look Vista or 7).
And no...you cant compare lemons with oranges,or freedos with ReactOS, or MS-Dos with WindowsXP. Or yes, if FreeDos is able to run FF 3.0...
nute wrote:
I wish someone would make a clone of Windows 3.1,
call it Windows lite, that will work on 286s on up.
286?Who have those processors?are still alive?I like your wish, but...imho Windows NT has more life in the future than 3.1

One of the reasons Windows 3.1 runs on old computers,
where ReactOS doesn't, is that the graphics requirements
of Windows 3.1 are very low.
nute wrote: Two downsides to running Windows 3.x on freedos:

1) It belongs to Microsoft still and it is not supported.

2) Freedos doesn't interact well with it.
Then post this in Freedos forum :)
nute wrote: My mouse, a logitech 3 button serial mouse, is on com4
where Windows 3.1 doesn't seem to have any drivers for
com4.
Well, you cant have the wish of using windows 3.1 in 286 with com4. If you want to use windows 3.1 then use ALL the supported hardware. Doesnt have sense to install Windows 3.1 and use a USB 2.0 mouse :)
nute wrote: what if someone could improve
freedos/Windows 3.x integration and release a service
pack that takes care of date and possibly other
problems in Windows 3.1?
We dont have the manpower for our NT goal,imagine to try to recreate a 3.1 ;)...impossible ;)
Image

nute
Posts: 251
Joined: Tue Aug 29, 2006 1:30 am

Re: ReactOS and older computers...

Post by nute » Fri Apr 10, 2009 11:30 pm

First off, my 486 doesn't have USB. It has four serial ports. Fortunately,
I replaced the first two and managed to get the mouse working under
Windows 3.1 which will only run in standard mode on top of freedos.

Second off, I'm not suggesting that this team clone Windows 3.1. I am
suggesting at most a little help to make freedos work better with Windows
3.1. I am also wondering if NT always needed a Pentium and what is so
wrong with supporting pre Pentium computers? Granted, firefox needs a
PII or later to run smoothly, but how much of that is the OS and how much
of that is firefox?

I know enough about Von Neumann architecture computers to know that
the 486 instruction set is a subset of the Pentium instruction set. Anything
compiled to run on a 486 will theoretically run on any Pentium. A 486 doesn't
have USB, so there should be some savings there. If optimization is done
properly, you should be able to simply set a Pentium flag and the OS should
compile for the Pentium. Programming as if you are on an older computer
forces you to program better.

Does the 486 not have virtual memory? I think that even the 386 has
that. Word size might be an issue. The amount of memory that 486s
support compared to Pentiums is an issue. The caches
tend to be smaller on 486s than they are on Pentiums. Pentiums have
branch prediction, which possibly doesn't exist on the 486. The 486
has a lot of what the Pentium has, without the complexity, at much
lower speeds. Okay, so no MMX, no SSE, no SSE2, no etcetera.

By the way, the 386 is apparently the most advanced computer that is
used on the International Space Station. The Pentium evidently can't
handle the space environment because the circuitry is too sensitive to
background radiation. There are times when a newer computer isn't
available and an older one has to be used. Wouldn't it be nice if there
was a free NT like OS that ran on older computers for those times?

In my case, a 486 is all I need to run Windows 98 to interface with
my old 8 bit color computer to provide a disk drive replacement. I'm
not sure about this, but a 486 might consume less power than a
comparable Pentium 4 system. For certain, 98se will have fewer
problems running on a 486 than it will running on a Pentium 4 drivers
wise.

I encourage designing ReactOS so that Pentium specific
instructions are isolated. There are other architectures like the
Power PC and Sun Sparc for example that are as fast as the
Pentium, but different at the instruction level.

It will be a while, at least a year, before ReactOS becomes stable.
Wouldn't it be nice if some level of Windows ran on top of a free
operating system comfortably before that?

Even the AMD Athlon and AMD Duron and later processors have
different instructions than the Intel Pentium does. Are there going
to be processor specific optimizations for AMD cpus in ReactOS?

Black_Fox
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Location: Czechia

Re: ReactOS and older computers...

Post by Black_Fox » Sat Apr 11, 2009 12:06 am

This sounds like 'Let's update ReactOS to use 8" monochromatic display and pre-286 computers, because some people still have these machines'. As a byproduct you could run ReactOS on a cash register</irony>.

nute
Posts: 251
Joined: Tue Aug 29, 2006 1:30 am

Re: ReactOS and older computers...

Post by nute » Sat Apr 11, 2009 12:28 am

First off, lower color density is faster. Second off, having a monochrome monitor even if you are running on
an AMD Core 2 duo is a good way to keep people from playing games. Third off, I did think when I
posted and frankly the keep the Pentium instructions isolated because there are AMD systems that don't
have the same instructions comment is very applicable. There are also Sun Sparcs, Alphas, Power PCs,
etcetera.

A little help on the freedos project to make the freedos kernel play better with Windows 3.1, even though Windows
3.1 is old and not NT based, would be very much appreciated. As far as the charge that I'm trying to get the
ReactOS community to clone Windows 3.1, I'm not. It looks like members of the freedos community are going
to organize to do that.

Haos
Test Team
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Re: ReactOS and older computers...

Post by Haos » Sat Apr 11, 2009 12:43 am

1. No 16bit support
2. No 80486 and lower cpu support. Using older instruction sets is bad for performance.
3. P1 is so low end i can not imagine anyone willing to use anything older. At AMD side, K5 is a perfect P1 replacement.
4. Please mind that this project is about 32bit or better NT. This counts out Win 3.11 (which is not a system) DOS (as it is) and specialized ISS software.
5. I remember playing really well on Hercules, so this is not going to deter anyone.
6. Different CPU architectures are different CPU architectures. If you want 486 support, please organize a port and maintain it yourself.

nute
Posts: 251
Joined: Tue Aug 29, 2006 1:30 am

Re: ReactOS and older computers...

Post by nute » Sat Apr 11, 2009 12:53 am

1) 386s and 486s are 32 bit computers capable of running 32 bit operating systems.
I never pushed 286's.

2) Prove that using a subset of the Pentium's instructions slows things down.

3) Most people want color when they play games, so monochrome is a deterrent.

4) If performance is all that counts, the OS needs to use the fastest and simplest
instructions. No branch and do payroll, hee hee.

hto
Developer
Posts: 2193
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Post by hto » Sat Apr 11, 2009 12:59 am

486 support does not actually require maintaining a different port, there are not so many changes needed.

Please everybody who want to add something to ReactOS, bring here a developer who will work on it. There is not enough manpower to implement everything what people suggest…

dark
Posts: 275
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Re:

Post by dark » Sat Apr 11, 2009 1:43 am

hto wrote:Please everybody who want to add something to ReactOS, bring here a developer who will work on it. There is not enough manpower to implement everything what people suggest…
You might have forgotten the bring money to pay for it option: http://www.reactos.org/wiki/index.php/CFI (which would obviously be a lot.)

Lone_Rifle
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Re: ReactOS and older computers...

Post by Lone_Rifle » Sat Apr 11, 2009 1:50 am

nute wrote: 1) 386s and 486s are 32 bit computers capable of running 32 bit operating systems.
I never pushed 286's.
You don't understand sarcasm. Get out much?
nute wrote: 2) Prove that using a subset of the Pentium's instructions slows things down.
I see you fail to understand that replacing a single Pentium instruction, say, cmpxchg8b with several other instructions that replicate the functionality and run on a 486 will obviously result in a slow down, since many more instructions will have to be executed. If you were sensible enough to actually google "emulating cmpxchg8b on a 486" instead of coming here to blab about things only you care about, you would have spotted a Linux patch which did the emulation through manipulation in memory.

Since you're ignorant, I will take the trouble to explain that doing said manipulation in memory is slow compared to using that a single instruction which operates on registers. It is blatantly obvious that modifying the codebase to accomodate a 486 will inconvenience Pentium-class and later processors, and making provisions (say, compiler macros, do you know what these are by the way?) to compile different lines of code given different compiler options for architecture is simply not worth the trouble.

Even disregarding all of the above, it's mere common sense to realise that if an instruction is present in a later architecture that wasn't present in a previous architecture, it is most likely supposed to implement some common programming idiom in a single, quick, convenient line of assembly. Going back to idiom as opposed to using this new instruction is nothing short of sheer stupidity, the latter being something I'm sure you're very closely familiar with. This is known as a computing advancement. Which, given your apparent fondness for old things, seems to be something you will also fail to understand.
nute wrote: 3) Most people want color when they play games, so monochrome is a deterrent.
I take it you don't want colour when you watch Youtube videos then, or look at your friend's photos on the internet. You must have fun watching snooker videos on a monochrome screen trying to figure out exactly which coloured balls the players are trying to pot.
nute wrote: 4) If performance is all that counts, the OS needs to use the fastest and simplest
instructions. No branch and do payroll, hee hee.
did you even realise that cmpxchg8b was indeed the fastest and simplest instruction to do something? your constant insistence of using the most common set of instructions (what you term using a subset of the Pentium instructions) underlines your ignorance to the fact that the presence of additional instructions is to get things done quicker.

hto wrote: ReactOS needs cmpxchg8b, which is only in Pentiums. Nobody volunteered to add support for 80486 since making use of this instruction. Simply compiling for i486 is not enough.
(a few posts later...)
nute wrote: If optimization is done
properly, you should be able to simply set a Pentium flag and the OS should
compile for the Pentium. Programming as if you are on an older computer
forces you to program better.
Ah, now we see the cause of your ignorance. You simply don't bother to read anything we write to you.
Last edited by Lone_Rifle on Sat Apr 11, 2009 2:54 am, edited 3 times in total.

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