DOSBox FAQ
20 Δεκ 2004 11:30 #3342
by adreasnaxos
DOSBox FAQ was created by adreasnaxos
Q. What is DOSBox?
A. DOSBox emulates a copy of good old DOS running on a 286 or 386 PC. An emulator is, in simple terms, a programme that runs on your computer that enables you to run other programmes that were developed for a different computer or operating system. DOSBox was specifically designed to run old games that will no longer run on modern operating systems. In our case, that usually means: Windows XP and MacOS X.
Q. Where did DOSBox come from?
A. Another planet. Well, it may as well have. We PC gamers tend to embrace a rather narrow world view that is confined to Microsoft Windows. Fortunately for us, there are a lot of Linux and MacOS X users out there who are avid gamers as well. They wanted to run DOS games on their computers and thus, we suspect, DOSBox was born. It runs on: Windows, Linux, and MacOS X, to name but a few. It is an open source project, and that means it's free for all of us to use... subject to certain restrictions, like that you don't try to sell it to your unsuspecting neighbour.
Q. Surely a modern computer can run some manky old DOS programmes!
A. If only it were that simple. But Microsoft have been trying to distance themselves from DOS for years. Among its most frustrating limitations: DOS can only do one thing at a time, and it is liable to crash if any programme does something... naughty. The break from DOS started with Windows NT (New Technology). NT got rid of the DOS limitations, but at the expense of backwards compatibility. Fundamentally, it no longer allowed programmes to directly access the hardware (which they were primarily doing for performance reasons), so old programmes that did this would no longer work in NT. But the system was more robust as a result. It was a trade-off. Windows XP is from the same stable as Windows NT, and thus you have the same problems trying to run those old 'misbehaving' programmes.
Q. How does DOSBox work?
A. Easy one
It uses a thing called the Simple DirectMedia Layer (SDL) to 'abstract' itself from the actual operating system and hardware. SDL provides a library of software that emulates (yup, there's that word again) old PC hardware, and makes it look the same on every operating system that it supports. Then DOSBox puts another layer on top of that that makes it appear as if DOS is running. But all this wonderfulness comes at a cost: it is relying on the fact that machines nowadays are many, many times faster than they were, say, 10 years ago...
Q. Could we have that again in plain English, please?
A. What DOSBox does is emulate (he's boring me now with this word, you say) a certain amount of 286/386 processor instructions per millisecond. Because this is done in software, you need a much more powerful machine to get the same kind of performance you got with that old 386 PC. The requirements vary from game to game. Attempting to keep up with a game like Realms of the Haunting that even stretched the limits of a high end 486 machine takes a lot more processing power than something like Hitchhiker's Guide to the Galaxy, a static text adventure with no sound. But this 'instructions per millisecond' concept has a hidden benefit: you can precisely control how fast a game runs, thus obviating the need for special 'slow down' programmes like Mo'Slo...
Q. So, what are the system requirements for DOSBox then?
A. As alluded to above, it depends. To get a decent frame rate out of Tex Murphy: Under a Killing Moon, for example, I found that you need at least a 2GHZ processor. Older DOS games, like most 2D adventures, can get away with much less. A 500MHZ PIII might do. You just have to experiment. But even then there are things you can do to increase performance in extreme cases. There is a parameter called 'frameskip', for example, that allows you to skip a number of frames when rendering graphics to get a better video frame rate at the expense of less quality. In the Windows world, DOSBox will run on: 95/98, ME, NT/2000/XP. But it is unlikely you will be running something like Win 98 on a machine that is powerful enough to emulate(!) even a slow 386, so beware. Having said that though... if you happen to be running Win 98 on a relatively fast machine, then it is actually easier to get old games running on DOSBox than it is to muck around with config.sys and autoexec.bat in an effort to get enough free memory, etc.
Q. OK, you've piqued my interest. How do I get this thing?
A. Go to the DOSBox project site and download the latest version for your operating system. At the time of writing, the version was: 0.63. It practically installs itself. In the case of Windows, just double-click on the .exe file you downloaded.
Q. Downloaded and installed it, what next?
A. Well... there are various graphical user interfaces (GUIs) for DOSBox that are supposed to make it easier for the average person on the street to use, but I'm one of those Luddites (relatively speaking, of course) who prefers to hand-edit configuration files. And it's really quite easy as there are only three things in the 'dosbox.conf' file you usually need to mess with to get any game running... you can probably see where this is all leading. Yes, I'm attempting to create an army of geeks to keep me in good company.
Q. So where is this 'dosbox.conf' file and how do I edit it?
A. If you installed DOSBox to the default folder, which would be something like:
C:\Program Files\DOSBox-0.63
Then just browse to there using Windows Explorer and open 'dosbox.conf' in Notepad. You will want to set up three important things:
Full screen mode by default. This is easily accomplished via:
fullscreen=true
How many 286/386 processor cycles DOSBox will emulate (I grow weary, really I do) per millisecond. For modern 2D games, a good starting point is:
cycles=6000
For 3D games, you'd want at least 2 or 3 times that. Once you are playing a game, you can use the Ctrl-F11 key combo (to slow a game down by 20 cycles) or Ctrl-F12 (to speed a game up by 500 cycles). Once you get the setting to the way you want it, Alt-Esc out of the game and DOSBox will tell you what the current setting is. You can then enter this value permanently into 'dosbox.conf'. Remember, you can also set this parameter artificially low (like: 2500, or even 1000) to slow down really old games that are running too fast.
There is a section at the very bottom of 'dosbox.conf' that is used to set up your CD-ROM and hard drives. You should just copy and paste the following lines into 'dosbox.conf', right over the [autoexec] section that is already there:
[autoexec]
# Lines in this section will be run at startup.
mount D D:\ -t cdrom
mount C C:\
C:
If your CD-ROM drive is not D:, then just substitute E: or whatever for the D: above.
Q. How do I start up DOSBox?
A. Just open a Command Prompt via:
Start -> All Programs -> Accessories -> Command Prompt
Then go to the folder where you installed DOSBox to, like:
cd \program files\dosbox-0.63
And finally, you enter:
dosbox
It's that simple! After DOSBox starts up, you just navigate to the folder where your game is installed, and run it with whatever DOS commands are necessary.
Q. My DOS game won't install in Windows. What do I do?
A. Start up DOSBox, and then install the game that way. Quite often an old game will do the sound configuration at install time, so you need to be running the game installation in DOSBox for this to work anyway.
Q. What sound settings should I configure for my DOS game?
A. I found that you get the best trade-off between quality and performance if you set the game up as if it's using a SoundBlaster Pro. If the game doesn't support a SoundBlaster Pro, then go for the basic SoundBlaster. Alternatively, you can let the game in question auto-detect the sound hardware. But of course, this will only work if you are running DOSBox at the time you install the game.
Q. Can I avoid having to edit 'dosbox.conf' each time I want to swap games?
A. A relatively simple solution that works for me: keep the copy of 'dosbox.conf' that is tailored for each game in that game's installation folder. Then just copy it over the top of the one in the C:\Program Files\DOSBox-0.63 folder before you start up that game.
Q. How do I configure a floppy drive?
A. In the [autoexec] section of 'dosbox.conf', just add the following line (right after the line that begins with "# Lines in this section..."):
mount A A:\ -t floppy
Q. My CD-ROM drive doesn't recognize my CDs, or I can't change CDs!
If the game is on a single CD, first thing to try is using Windows Explorer to determine the CD's label and then feeding it to DOSBox like this:
mount D D:\ -t cdrom -label DISK1
If that doesn't work you can try drilling down progressively closer to the hardware. As mentioned earlier, the hardware is abstracted by the SDL library, so you can't directly access it. However, to solve problems reading CDs and the like, because there are so many variations from different manufacturers, you can get closer to the hardware Next, you can try using lower level SDL support, like this:
mount D D:\ -t cdrom -usecd 0
Usually, your CD-ROM drive will be number 0, but you can use: 'mount -cd' from within DOSBox to determine the number if you're not sure. If that still doesn't do it for you, then you can go the final step and specify input/output control (IOCTL):
mount D D:\ -t cdrom -usecd 0 -ioctl
This will only work for Win NT/2000/XP. In the case of Win 95/98, try using ASPI via:
mount D D:\ -t cdrom -usecd 0 -aspi
Q. What if the sound doesn't work?
A. The section in 'dosbox.conf' that relates to the setting up of your sound card looks like this:
[sblaster]
# type -- Type of sblaster to emulate:none,sb1,sb2,sbpro1,sbpro2,sb16.
# base,irq,dma,hdma -- The IO/IRQ/DMA/High DMA address of the SoundBlaster.
# mixer -- Allow the SoundBlaster mixer to modify the dosbox mixer.
# oplmode -- Type of OPL emulation: auto,cms,opl2,dualopl2,opl3.
# On auto the mode is determined by sblaster type.
# oplrate -- Sample rate of OPL music emulation.
type=sb16
base=220
irq=7
dma=1
hdma=5
mixer=true
oplmode=auto
oplrate=22050
Usually, the only thing that will differ from game to game is the IRQ (Interrupt Request line). For instance, most Sierra 'Quest' games expect the IRQ to be 5, instead of the default which is 7. So, for these games you would set:
irq=5
If in doubt, either the sound set-up for the game, or the manual, should give you some clue as to what the possibilities/expectations for the IRQ are.
Another thing that could happen regarding sound is that your PC will normally be utilizing full hardware sound acceleration - something that did not even remotely exist back in the good old DOS days. If you suspect this might be a problem, try the following:
Start -> Run -> dxdiag.exe
Then go to the Sound tab, and knock the 'Hardware Sound Acceleration Level' down a notch or two. Start up DOSBox again, and see if that gets you some sound.
Q. What if the sound is stuttering or the video is going too slow?
A. The sound is rarely going to be crystal clear because we are not using real sound hardware, remember? But if there are too many 'clicks', or the sound is cutting out, or the video is going too slow in a 3D game and you just keep spinning around when you try to move... then you are probably trying to emulate (sigh) more cycles per millisecond than your machine is capable of handling. There are several things you can try to remedy this problem:
You can reduce the number of instructions DOSBox is trying to... execute per millisecond via Ctrl-F11 (use Ctrl-F12 to increase again). Once you get the setting to the way you want it, Alt-Esc out of the game and DOSBox will tell you what the current setting is. You can then enter this value permanently into 'dosbox.conf' via:
cycles=?
Likewise, you can try skipping video frames via Ctrl-F8 (use Ctrl-F7 to add them back in). Skipping frames will decrease processor requirements at the expense of video quality. You set this value permanently into 'dosbox.conf' via:
frameskip=?
Q. The video is looking a bit strange. Anything I can do?
A. This problem only happens on certain machines and most likely stems from trying to run with full hardware acceleration. Go to your Windows desktop, right-click on 'Properties' to bring up Display Properties, then choose:
Settings -> Advanced -> Troubleshoot
Crank the 'Hardware acceleration' setting down a notch or two, then try starting up DOSBox again.
Steve Metzler (Quandary, 16.12.2004)
A. DOSBox emulates a copy of good old DOS running on a 286 or 386 PC. An emulator is, in simple terms, a programme that runs on your computer that enables you to run other programmes that were developed for a different computer or operating system. DOSBox was specifically designed to run old games that will no longer run on modern operating systems. In our case, that usually means: Windows XP and MacOS X.
Q. Where did DOSBox come from?
A. Another planet. Well, it may as well have. We PC gamers tend to embrace a rather narrow world view that is confined to Microsoft Windows. Fortunately for us, there are a lot of Linux and MacOS X users out there who are avid gamers as well. They wanted to run DOS games on their computers and thus, we suspect, DOSBox was born. It runs on: Windows, Linux, and MacOS X, to name but a few. It is an open source project, and that means it's free for all of us to use... subject to certain restrictions, like that you don't try to sell it to your unsuspecting neighbour.
Q. Surely a modern computer can run some manky old DOS programmes!
A. If only it were that simple. But Microsoft have been trying to distance themselves from DOS for years. Among its most frustrating limitations: DOS can only do one thing at a time, and it is liable to crash if any programme does something... naughty. The break from DOS started with Windows NT (New Technology). NT got rid of the DOS limitations, but at the expense of backwards compatibility. Fundamentally, it no longer allowed programmes to directly access the hardware (which they were primarily doing for performance reasons), so old programmes that did this would no longer work in NT. But the system was more robust as a result. It was a trade-off. Windows XP is from the same stable as Windows NT, and thus you have the same problems trying to run those old 'misbehaving' programmes.
Q. How does DOSBox work?
A. Easy one
It uses a thing called the Simple DirectMedia Layer (SDL) to 'abstract' itself from the actual operating system and hardware. SDL provides a library of software that emulates (yup, there's that word again) old PC hardware, and makes it look the same on every operating system that it supports. Then DOSBox puts another layer on top of that that makes it appear as if DOS is running. But all this wonderfulness comes at a cost: it is relying on the fact that machines nowadays are many, many times faster than they were, say, 10 years ago...Q. Could we have that again in plain English, please?
A. What DOSBox does is emulate (he's boring me now with this word, you say) a certain amount of 286/386 processor instructions per millisecond. Because this is done in software, you need a much more powerful machine to get the same kind of performance you got with that old 386 PC. The requirements vary from game to game. Attempting to keep up with a game like Realms of the Haunting that even stretched the limits of a high end 486 machine takes a lot more processing power than something like Hitchhiker's Guide to the Galaxy, a static text adventure with no sound. But this 'instructions per millisecond' concept has a hidden benefit: you can precisely control how fast a game runs, thus obviating the need for special 'slow down' programmes like Mo'Slo...
Q. So, what are the system requirements for DOSBox then?
A. As alluded to above, it depends. To get a decent frame rate out of Tex Murphy: Under a Killing Moon, for example, I found that you need at least a 2GHZ processor. Older DOS games, like most 2D adventures, can get away with much less. A 500MHZ PIII might do. You just have to experiment. But even then there are things you can do to increase performance in extreme cases. There is a parameter called 'frameskip', for example, that allows you to skip a number of frames when rendering graphics to get a better video frame rate at the expense of less quality. In the Windows world, DOSBox will run on: 95/98, ME, NT/2000/XP. But it is unlikely you will be running something like Win 98 on a machine that is powerful enough to emulate(!) even a slow 386, so beware. Having said that though... if you happen to be running Win 98 on a relatively fast machine, then it is actually easier to get old games running on DOSBox than it is to muck around with config.sys and autoexec.bat in an effort to get enough free memory, etc.
Q. OK, you've piqued my interest. How do I get this thing?
A. Go to the DOSBox project site and download the latest version for your operating system. At the time of writing, the version was: 0.63. It practically installs itself. In the case of Windows, just double-click on the .exe file you downloaded.
Q. Downloaded and installed it, what next?
A. Well... there are various graphical user interfaces (GUIs) for DOSBox that are supposed to make it easier for the average person on the street to use, but I'm one of those Luddites (relatively speaking, of course) who prefers to hand-edit configuration files. And it's really quite easy as there are only three things in the 'dosbox.conf' file you usually need to mess with to get any game running... you can probably see where this is all leading. Yes, I'm attempting to create an army of geeks to keep me in good company.
Q. So where is this 'dosbox.conf' file and how do I edit it?
A. If you installed DOSBox to the default folder, which would be something like:
C:\Program Files\DOSBox-0.63
Then just browse to there using Windows Explorer and open 'dosbox.conf' in Notepad. You will want to set up three important things:
Full screen mode by default. This is easily accomplished via:
fullscreen=true
How many 286/386 processor cycles DOSBox will emulate (I grow weary, really I do) per millisecond. For modern 2D games, a good starting point is:
cycles=6000
For 3D games, you'd want at least 2 or 3 times that. Once you are playing a game, you can use the Ctrl-F11 key combo (to slow a game down by 20 cycles) or Ctrl-F12 (to speed a game up by 500 cycles). Once you get the setting to the way you want it, Alt-Esc out of the game and DOSBox will tell you what the current setting is. You can then enter this value permanently into 'dosbox.conf'. Remember, you can also set this parameter artificially low (like: 2500, or even 1000) to slow down really old games that are running too fast.
There is a section at the very bottom of 'dosbox.conf' that is used to set up your CD-ROM and hard drives. You should just copy and paste the following lines into 'dosbox.conf', right over the [autoexec] section that is already there:
[autoexec]
# Lines in this section will be run at startup.
mount D D:\ -t cdrom
mount C C:\
C:
If your CD-ROM drive is not D:, then just substitute E: or whatever for the D: above.
Q. How do I start up DOSBox?
A. Just open a Command Prompt via:
Start -> All Programs -> Accessories -> Command Prompt
Then go to the folder where you installed DOSBox to, like:
cd \program files\dosbox-0.63
And finally, you enter:
dosbox
It's that simple! After DOSBox starts up, you just navigate to the folder where your game is installed, and run it with whatever DOS commands are necessary.
Q. My DOS game won't install in Windows. What do I do?
A. Start up DOSBox, and then install the game that way. Quite often an old game will do the sound configuration at install time, so you need to be running the game installation in DOSBox for this to work anyway.
Q. What sound settings should I configure for my DOS game?
A. I found that you get the best trade-off between quality and performance if you set the game up as if it's using a SoundBlaster Pro. If the game doesn't support a SoundBlaster Pro, then go for the basic SoundBlaster. Alternatively, you can let the game in question auto-detect the sound hardware. But of course, this will only work if you are running DOSBox at the time you install the game.
Q. Can I avoid having to edit 'dosbox.conf' each time I want to swap games?
A. A relatively simple solution that works for me: keep the copy of 'dosbox.conf' that is tailored for each game in that game's installation folder. Then just copy it over the top of the one in the C:\Program Files\DOSBox-0.63 folder before you start up that game.
Q. How do I configure a floppy drive?
A. In the [autoexec] section of 'dosbox.conf', just add the following line (right after the line that begins with "# Lines in this section..."):
mount A A:\ -t floppy
Q. My CD-ROM drive doesn't recognize my CDs, or I can't change CDs!
If the game is on a single CD, first thing to try is using Windows Explorer to determine the CD's label and then feeding it to DOSBox like this:
mount D D:\ -t cdrom -label DISK1
If that doesn't work you can try drilling down progressively closer to the hardware. As mentioned earlier, the hardware is abstracted by the SDL library, so you can't directly access it. However, to solve problems reading CDs and the like, because there are so many variations from different manufacturers, you can get closer to the hardware
Next, you can try using lower level SDL support, like this:mount D D:\ -t cdrom -usecd 0
Usually, your CD-ROM drive will be number 0, but you can use: 'mount -cd' from within DOSBox to determine the number if you're not sure. If that still doesn't do it for you, then you can go the final step and specify input/output control (IOCTL):
mount D D:\ -t cdrom -usecd 0 -ioctl
This will only work for Win NT/2000/XP. In the case of Win 95/98, try using ASPI via:
mount D D:\ -t cdrom -usecd 0 -aspi
Q. What if the sound doesn't work?
A. The section in 'dosbox.conf' that relates to the setting up of your sound card looks like this:
[sblaster]
# type -- Type of sblaster to emulate:none,sb1,sb2,sbpro1,sbpro2,sb16.
# base,irq,dma,hdma -- The IO/IRQ/DMA/High DMA address of the SoundBlaster.
# mixer -- Allow the SoundBlaster mixer to modify the dosbox mixer.
# oplmode -- Type of OPL emulation: auto,cms,opl2,dualopl2,opl3.
# On auto the mode is determined by sblaster type.
# oplrate -- Sample rate of OPL music emulation.
type=sb16
base=220
irq=7
dma=1
hdma=5
mixer=true
oplmode=auto
oplrate=22050
Usually, the only thing that will differ from game to game is the IRQ (Interrupt Request line). For instance, most Sierra 'Quest' games expect the IRQ to be 5, instead of the default which is 7. So, for these games you would set:
irq=5
If in doubt, either the sound set-up for the game, or the manual, should give you some clue as to what the possibilities/expectations for the IRQ are.
Another thing that could happen regarding sound is that your PC will normally be utilizing full hardware sound acceleration - something that did not even remotely exist back in the good old DOS days. If you suspect this might be a problem, try the following:
Start -> Run -> dxdiag.exe
Then go to the Sound tab, and knock the 'Hardware Sound Acceleration Level' down a notch or two. Start up DOSBox again, and see if that gets you some sound.
Q. What if the sound is stuttering or the video is going too slow?
A. The sound is rarely going to be crystal clear because we are not using real sound hardware, remember? But if there are too many 'clicks', or the sound is cutting out, or the video is going too slow in a 3D game and you just keep spinning around when you try to move... then you are probably trying to emulate (sigh) more cycles per millisecond than your machine is capable of handling. There are several things you can try to remedy this problem:
You can reduce the number of instructions DOSBox is trying to... execute per millisecond via Ctrl-F11 (use Ctrl-F12 to increase again). Once you get the setting to the way you want it, Alt-Esc out of the game and DOSBox will tell you what the current setting is. You can then enter this value permanently into 'dosbox.conf' via:
cycles=?
Likewise, you can try skipping video frames via Ctrl-F8 (use Ctrl-F7 to add them back in). Skipping frames will decrease processor requirements at the expense of video quality. You set this value permanently into 'dosbox.conf' via:
frameskip=?
Q. The video is looking a bit strange. Anything I can do?
A. This problem only happens on certain machines and most likely stems from trying to run with full hardware acceleration. Go to your Windows desktop, right-click on 'Properties' to bring up Display Properties, then choose:
Settings -> Advanced -> Troubleshoot
Crank the 'Hardware acceleration' setting down a notch or two, then try starting up DOSBox again.
Steve Metzler (Quandary, 16.12.2004)
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23 Δεκ 2004 02:52 #3360
by Real NC
Sig? We don't need no stinking sig!
members.lycos.co.uk/realnc qtads.sf.net
Replied by Real NC on topic DOSBox FAQ
Βασικά, ο καλύτερος DOS emulator που έχω δει είναι ο Pentium 133 με MS DOS 6.22 που έχω στη γωνία... 
Sig? We don't need no stinking sig!
members.lycos.co.uk/realnc qtads.sf.net
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23 Δεκ 2004 21:23 #3363
by adreasnaxos
Replied by adreasnaxos on topic DOSBox FAQ
Mπάς κι υπάρχει καί κανένα περισσευούμενο ποντίκι πεταμένο στήν άλλη γωνία; (γιά 486 τό θέλω).Real NC wrote: Βασικά, ο καλύτερος DOS emulator που έχω δει είναι ο Pentium 133 με MS DOS 6.22 που έχω στη γωνία...
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