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What is an emulator ?
=====================
an emulator is an something that simulating something . an emulator
can be a simply machine or an pice of an software that runs on
your computer . Which means a machine that simulates another machine.


Why emulators ?
===============
When you install and run windows operating sysetm you are restricted to
a one operating system and a one machine architure. what about you can
feel , the old ms-dos games are not running under the current versions
of the windows . That the place you needs to get an emulator . In this
case you really can use the DOSBOX emulator .

[img]http://img182.imageshack.us/img182/3654/skynetunderdosboxcv9.gif[/img]

[img]http://img182.imageshack.us/img182/759/skynetunderdosbox1ia7.gif[/img]

[img]http://img182.imageshack.us/img182/483/skynetdosbox2ya6.gif[/img]

SKYNET game is running under the DOSBOX in winxp]

These are the screenshots that DOSBOX running SKYNET game. (SKYNET is
an good game however that was too old now ).

Yeh ! You really can use emulators to play those old games under the
windows . But what about this . you really can use them to run the TV
games like nes also . Nes means a completely different processor
architure than the x86 . And there are really nice games that you can
find for it . In this nes games you rally insert an Card into the game
set and let the ROM inside that Card to load as a game . But when you
are running those nes games under the emulator, you can download free
but illeagal , *.nes files to drag and drop into your emulator . and
then it really opens the game that you experienced inside your TV game
set with an card.

[img]http://img182.imageshack.us/img182/3540/tvgamesrunningunderxoue2.gif[/img]
[nes game running mario under an emulator]

If you are a really a game killer like me , you will find this as an time
wasting machine. But I really use emulators for some different purpose also
I have an windows xp computer , then i needs to really boot up a operating
system that supports an different processor system .What should I do ? I really
got software emulators to work for that . For an example for the intel x86
family you can find a good free emulator called an bochas. bochas is an
emulator that integraded with an debugger .Thus beacuse that emulator is
integraded with an debugger you really slower can run that you are emulating.


[img]http://img165.imageshack.us/img165/5141/screenshotbhocsrunningure0.gif[/img]
[screenshot bhocs running under the xp puppy boot screen]

However the bohas is very slow relatively to the other emulators when comparing.
But you can use the qemu, another emulator that I freely find on the internet.
I runs puppy under this emulator you can see the screenshots , and I really
experienced a good performance under qemu when comparing to the bochas.

[img]http://img266.imageshack.us/img266/5311/puppyunder64bitxpof6.gif[/img]

screenshot of the qemu running pupuy linux].
HMMM ! really you can experienced with more and more operating systems using
emulators . Have a fun with emulators .


How to find those emulators .
=============================
to find the emulators like qemu you can really google it .use these
search strings .
"qemu"+"windows"+"download"
and you will really find an link to download qemu. I really happy
with the qemu , thus beacuse it can execute protected mode os es and
it has a very good speed .

you can download those freedos img files form here.

www.freedos.org

you can download the dosbox here

http://www.dosbox.com/download.php?main=1

when you downloading the DOSBOX you have to make sure that you are

downloading the dosbox for windows.

If you are really interested to the emulator with an debugger you
can use bochs . Bochs for the kernel level developers . When you
experimenting with the operating system kernels , Bochas is a
great tool that you can use . If you are an kernel programmer you
want to know the inside and outside of your operating system .Therefore you
really needs an tool like bohcs.

DOSBOX
======
you can download the dosbox at no cost or little cost . form the web site
. You really download dosbox for free. Its freely av . but a real
stroy is that if you are a game killer you need dosbox .DOSBOX is mostely
using for the running old MS-DOS games under the windows. However it aslo
can use to experiment those old ms-dos programs and you even can run the
windows 3.1 operating system under it . Really ! I like to play the SKYNET
under it . SKYNET is a game that needs the protected mode , but you can run
it under the DOSBOX .that means DOSBOX supports that feature. or else you
can also boots up a little tiny operating sysetm under the dosbox , for an
example I boots freedos under it .

[img]http://img101.imageshack.us/img101/5200/dosboxfreedosho6.gif[/img]

[freedos running under the dosbox]

Note: freedos is an real time operating system that made for the x86 computers
,representing the old dead dos world .You can download that boot image at
(means *.img file) for the freedos website .For more operating systems that are
free you can visit to the web site that www.freeos.com for having a fun with
it .

I really tries to load small linux version (10Meagabyte) , under the dosbox , but that
really hurts . Does not works . Howver you can load it under the qemu . I will show
how to.

Running FREEDOS under the DOSBOX
================================
Did you got freedos *.img file form their freedos site ? Wonderful .Really wants to
run it . Oky there are two ways that you can choose . The first one is you can
burn it into a floppy (usually img file) or burn into a CD-ROM (usually iso file). You
can use the linux dd command to copy the img file into your floppy or bootflash disk .
that means you are going to physically reboot your computer and boot it physically.

The second method is load it using an emulator. you can use an emulator DOSBOX to run it
. DOSBOX boot command let you to boot an img file , as a way it loads an new operating
system .So download the dosbox and install it and run it . YOu will find an screen like
this an prompt like z:\

[img]http://img142.imageshack.us/img142/3291/dosboxwelcomelk5.gif[/img]


[dosbox ]

You should unzip your freedos download into a folder called c:\newfolder, (make a floder called
c:\newfloder and unzip it ).
so the *.img file should be inside your c:\newfolder ,
then you start dosbox ,
One thing that you have to remember that your system , your filesystem , your operating
system is completely independent form the whatever running on DOSBOX . But you can mount
your c:\newfolder as an disk .under the dosbox this is the command .

mount c c:\newfloder
Then you will get the C:\newfolder as the c: under your dosbox

then you can type c: to move to the c:
C:\> dir
Directory of C:\.
. <DIR> 10-02-2002 14:45
.. <DIR> 01-01-1980 0:00
FDBOOT IMG 1,474,560 01-02-2002 20:32

like this you can get when you have the FDBOOT.img file as in the c: but it really in the
c:\newfloder. But the DOSBOX sees it as the c:
then you can run it .

C:\>boot fdboot.img
and you will recieve the screen that loads freedos bootup screen.

!!!Really !had the fun inoguhf with the freedos . Let's try to emulate the linux under an
emulator .


Here that above screenshot is an puppy linux running under QEMUL emulator inside windows .you
really does not believe that thing if I really cut out the other background in this screenshot.
sorry for the slow download times . However donwload the qemu now . unzip the zip file into you
foler that any you like . In my it was c:\qemu-0.9.0-windows\ however , then go to the
command line and change to that directory.

c:\qemu-0.9.0-windows>

like this . in this directory you can find qemu.exe file . that was the emulator that we are need
to run. so what to run ? well we needs to download a version of small linux form the internet or you
can use the small linux version that comes with the emulator something 10meagabytes . I said you
earliear that i failed to run it under the dosbox . However you does not even needs to go to the
command prompt even if you need to run only it . you can simply double click the bat file in
the qemu directory to start a little version of linux that comes with it . However if you
really needs to load a another linux version you really needs to read the documentation that
comes under that emulator . the doc are there . I don't really read the docs. But I read the
above metioned bat files code and knows how to load linux . I download the iso image form the
internet puppy.iso and hit this command in the command line


c:\qemu-0.9.0-windows> qemu.exe -L . -m 256 -cdrom puppy.iso -boot d

as you can see the boot screen and the screenshot under puppy is above . try it find it !

Then i got the boot screen of the puppy linux . Do you really wonder why I mention that puppy linux
, what about other linux distributions . But I love puppy , buy my best is knoppix . you can download
puppy linux iso files in this web site .


What about the Bohch emulator ?
That will be too little compilcated for a beginer who are interested to emulators . If you
really interested please email me if you stuck . I can help what I know and simply said I
don't know if I really or have not time I will say don't know .You you really interesting
about the kernel programming and operating system design you really needs a tool like an
bohch , unlike other emulators you can , for an example if there is an kernel pannic in your
developing operating system you need a tool like this . Something that is similar to the
black screen of death inside windows , that the places that you never recieve a crash dump
file . then using this shuch a tool you can trace what's went wrong. There are some debuggers
that running under or with this emulator for an example softICE . softICE is an hardware level
debugger , means that you can debug the windows kernel inside softice too . That its name
soft ice , an software in-circuit-emulator! , that mainly used in the developing the embedded
system operating system kernels .For an example look at what I got when I loading puppy linux
under bohcs on the console window . when puppy linux initializes the keyboard , look carefully.
But this really takes my 11/2 hours to load up to puppy to this stage.(!!!!!Bochs is slow!!!)

[img]http://img340.imageshack.us/img340/6154/puppykeyboardinitializeqb9.gif[/img]


[consloe output of bhocs when loading the keyboard driver]


Hi my name is Sanzilla !
>>>>> I like beatiful person like me , beatiful_person++
>>>>> I like good people like me , good_people++
>>>>> I like Smart people like me , smart_one ++
<<<<< I hate dirty people , dirty_people--
<<<<< I hate bad people , bad_people--
<<<<< I hate curl evil people , evil_people--

If you beatiful , nice , smart and good you welcome !

If you like my little article about emulators or does not like , or have bugs please email me !
sanzillajackcat@gmail.com
sandundhammikaperera@yahoo.com

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