So USB or PS/2?

[kruluk]

I have been reading some about the difference between USB and PS/2 but still don't quite understand the difference. I am going to be buying an IPac either today or tomorrow. I understand that the USB version comes with a "conversion cable" so I guess it just plugs into a USB port on the computer? But what I don't understand is the PS/2 version. Does the PS/2 version plug into the purple keyboard port on the back of computers?

Also I am not really understanding the difference in setting up a PS/2 IPac or a USB IPac is one easier than the other? People say USB won't work in DOS? Does that mean if you want to use USB you have to use Mame32 and can't use the command line version? Does that also mean that the USB version would not work in MameWah? Be cause isn't MameWah running in DOS?

  I really have tried reading about this stuff but it seems like every article I read simply assumes you understand what they mean by the USB and PS/2 and that is like a different language to me  But I am trying to learn! 

[AcidArmitage]

it doesn't really matter which one you would pick other than what port you wanna use at the back of your computer, USB is more common nowadays but yes PS/2 is the purple keyboard port. As for DOS, nobody really uses DOS anymore (including Mamewah) so I wouldn't worry about that

[Blanka]

I would say go for the USB cable. There are still some nitwits including purple ports on mobo's, but another 2 years and they are gone forever. For the emulators is does not matter. All emulators accept command line, whether they are for Windows, Linux, DOS or OS X. I also don't know if you can program the IPAC over PS2. I guess PS2 is a one-way protocol.

[fronty]

.

[Cananas]

If you have an PS/2 connection, I will go for PS/2. What other thing you could connect there? Reserve the usb port for other things. Dont't worry if you can connect a keyboard. The ipac have a Bypass for a keyboard connection.

I have and Ipac Ps/2. I can program it and I can press 10 buttons (the fingers in my hands) simultaneous without problems.

[AndyWarne]

Also I am not really understanding the difference in setting up a PS/2 IPac or a USB IPac is one easier than the other? People say USB won't work in DOS? Does that mean if you want to use USB you have to use Mame32 and can't use the command line version? Does that also mean that the USB version would not work in MameWah? Be cause isn't MameWah running in DOS?

The command-line version of Mame does not run in DOS. I think you are confusing "Windows Command Line" with DOS. This is not DOS.
DOS is not practical on modern hardware for all kinds of reasons, best not to use it because you are likely to end up with a machine which is slow, with choppy video and sound (or no sound at all on many motherboards which dont have any DOS sound drivers). Video will not be accelerated, no D3D, no stretch.

So USB can be used on all practical Mame installations. PS/2 cant always be used as it has been dropped by all the big-name manufacturers although many motherboards still have PS/2 ports.

[AndyWarne]

I really have tried reading about this stuff but it seems like every article I read simply assumes you understand what they mean by the USB and PS/2 and that is like a different language to me  But I am trying to learn! 

Basically if you go with PS/2 then your computer will see your joysticks and buttons as one glorified keyboard. E.g. press a button and your computer sees it as if you were pressing a key on the keyboard.

With USB your computer will see your joysticks and buttons as an gamepad with lots (and I mean lots) of buttons. You press a button and your computer sees it as exactly that (a gamepad button).

There are deeper technical differences which you can search the forums. Basically PS/2 has a limit of simultaneous keypresses which keyboard encoders circumvent in their own way. USB encoders don't have this problem and benefit from being recognized as gaming devices.

Ummm.... Unfortunately the above information is pretty much all incorrect...not sure where to start really, its just, well, all wrong..

[Jack Burton]

To start with, USB keyboards aren't gamepads, they're keyboards. 

[CheffoJeffo]

I think that FrontyDev is confusing USB and PS/2 with keyboard encoders and gamepad encoders.

As far as the simultaneous keypress issue goes, here is my recollection as posted in a recent thread on the subject:

USB keyboards have a maximum of 6 simultaneous keypresses (plus modifier keys -- Ctrl, Alt and Shift).

Last I heard, in USB mode, the IPac has a maximum of 16 simultaneous keypresses (plus modifier keys).

USB gamepads have a maximum of 64 simultaneous inputs.

NOTE: The above is my recollection based on the "Great USB vs PS/2 and Keyboard vs Gamepad ThreadWars of 2005"(tm)

For more info, I refer the ambitious reader to TigerHeli's Arcade Interfaces Page, which includes technical discussions by the major participants of said ThreadWars.

[AcidArmitage]

who presses that many keys!


but yea.. the Ipac will alwaysbe seen as a keyboard... and the GPwiz will be seen as a gamepad (and then can be converted to keypresses with joy2key)


ANYWAYS just go with USB... its easier for everybodyyyyy 


Edit:woops

[CheffoJeffo]

KeyWiz is a keyboard encoder.

GPWiz is a gamepad encoder.

[fronty]

.

[CheffoJeffo]

If I had to choose, I would rather that people chime in to point out massive errors than chime in to complain that their massive errors were pointed out.

This time, however, we got lucky and got both!

[CathalDublin]

USB
ps2 is dying, its not on that many motherboards anymore

[Jack Burton]

who presses that many keys!

Remember that includes all players.  So for a 4 player game a maximum of 6 simultaneous key presses is unacceptable.

In fighting games it's common for 2 players to go over that limit.

[CathalDublin]

who presses that many keys!

Remember that includes all players.  So for a 4 player game a maximum of 6 simultaneous key presses is unacceptable.

In fighting games it's common for 2 players to go over that limit.

or even 4

[RandyT]

PS/2 cant always be used as it has been dropped by all the big-name manufacturers although many motherboards still have PS/2 ports.

Speaking of incorrect....

The same folks predicting the demise of the PS/2 connector "in a couple of years" made that same prediction almost 5 years ago.  I argued with them then, and I'll do it again now.  It's still present on far more motherboards being manufactured currently than not.  One needs only to go to the major manufacturers and look at their current offerings.  I went o the first "big-name" manufacturer that popped in my head (ASUS) and it's quite obvious that they have absolutely not "dropped" PS/2.  Even the current "Mini-ITX" boards from VIA still have the connectors, because those boards, unlike their other smaller offerings, have room for them.

It's still there because consumers expect it to be there, and it doesn't cost the manufacturers much to include it.  Most of the systems you will find out there that don't have a PS/2 connection are designed specifically for very low cost, or very small form factor.  Anyone who claims they know when the PS/2 connector is going away is at best, speculating and at worst, deliberately attempting to mislead.

If you have a PS/2 port on your system (and you probably do) and you aren't using it, it's an excellent, and trouble-free connection point for your arcade controls.

RandyT

[CheffoJeffo]

Did Fronty just pull an ahigh ?

Was it something we said ?

 

[ghettodish]

I had my i-pac connected to ps2, and a second keyboard to USB. The computer saw the USB one as #1, and the ps2 as #2. After I set up mame i unplugged the USB keyboard. The computer then made the ps2 (I-Pac) the #1 keyboard and I lost all my settings.

I went to Target, got a ps2 keyboard and plugged it into the I-pac like I should have done in the first place. Re-did my settings and all is well now.

I'm glad I went with the ps2. It means I have a free USB port for my Tron spinner and I don't have to use a crappy USB hub.

[Blanka]

PS/2 cant always be used as it has been dropped by all the big-name manufacturers although many motherboards still have PS/2 ports.

Speaking of incorrect....

The same folks predicting the demise of the PS/2 connector "in a couple of years" made that same prediction almost 5 years ago.  I argued with them then, and I'll do it again now.  It's still present on far more motherboards being manufactured currently than not.  One needs only to go to the major manufacturers and look at their current offerings.  I went o the first "big-name" manufacturer that popped in my head (ASUS) and it's quite obvious that they have absolutely not "dropped" PS/2.  Even the current "Mini-ITX" boards from VIA still have the connectors, because those boards, unlike their other smaller offerings, have room for them.

It's still there because consumers expect it to be there, and it doesn't cost the manufacturers much to include it.  Most of the systems you will find out there that don't have a PS/2 connection are designed specifically for very low cost, or very small form factor.  Anyone who claims they know when the PS/2 connector is going away is at best, speculating and at worst, deliberately attempting to mislead.

If you have a PS/2 port on your system (and you probably do) and you aren't using it, it's an excellent, and trouble-free connection point for your arcade controls.

RandyT

This time it is different. We are about to say goodbye to the ATX mobo-form factor for >80% of all desktops, and consider most computers sold are notebooks! Who buys a seperate mobo nowadays? Small is the new form factor, and that kills space for a PS2 port. Especially when there is a new battle between HDMI/DP/DVI that needs a playing field on the port-bay somewhere!

Intel does not get it right now with this crap. Where is DVI? What is that GODZILLA PORT doing there? It looks like a MAC PLUS FLOPPY PORT. What TF is GMA 950, my Commodore 64 had more graphics power! Looking at the mounting holes, I guess you are supposed to put it in a huge tower either with the giant void filled with concrete to make it "dead" silent, with the giant void as hamster cage with a running wheel to cool the Atom or to accommodate a 12 disk floppy raid. That GODZILLA port is a custom 12 channel USB raid port after all! Although I have to say 60 euros for almost a new computer is pretty much ok.


Asus packs the same chipset a lot better:

This EEE box is amazing. It can replace 90% of all business desktops and is a whopping 220 euro including a Windows licence! BTW, do you see the PS2 port on that?
But Nvidia gives us an idea, more compact than a flopyy drive was in 1984!, of what a PC will be like next year (one of the big toasting-iron makers goes for low-power video chips now!):

This years atom is still a slouch, but the 2011 one baked on 32nm is like a good core2quad today! If the videocard makers manage to create a compact PCI-X variation and to get real 3D power back under 20 watt or so, our kids won't get the concept of a miditower anymore.

Résumé: in 2011 the desktop looks like an EEE-box, has the power of a Q9550 and the videopower of a 8800GT, uses 30 watts, costs 200 bucks, still has no Blu-Ray and definitely has NO PS2 port and YOU would be stupid to put anything else in a MAME box! The cut power bill moving here from that old P4 you put in today makes it earn itself back within 2 years of moderate use.

[richms]

Friend got a motherboard with just one PS2 on it - cant recall if its a mouse or keyboard one - but they are going away slowly.

[Hoopz]

Did Fronty just pull an ahigh ?

Was it something we said ?

 

Damn.  I thought the ahigh reference was funny but seeing someone kill there account is never a good thing. 

[RandyT]

This time it is different. We are about to say goodbye to the ATX mobo-form factor for >80% of all desktops, and consider most computers sold are notebooks! Who buys a seperate mobo nowadays? Small is the new form factor, and that kills space for a PS2 port. Especially when there is a new battle between HDMI/DP/DVI that needs a playing field on the port-bay somewhere!

The reality of these tiny, power-packed, power efficient devices is still a long way off.  The value is also questionable.  Small costs more, and is less convenient for a lot of applications.  Separate boxes and power supplies for all of your peripherals and storage devices?  No expansion or upgrade options outside of USB? Really?  No thanks......  For a dedicated application like a MAME box, assuming the price becomes something other than obscene for the "good stuff", maybe.  But once you add room in the box for a couple of drives, it's pointless to pay more for a smaller MOBO.  Simple economics.....

Keep in mind that the "Euro" market differs from the US market as well. 

Friend got a motherboard with just one PS2 on it - cant recall if its a mouse or keyboard one - but they are going away slowly.

It still has the keyboard PS/2 port, which is the important one.  The fact that they dropped the mouse and kept the keyboard should prove to the skeptics that the value of that port is still very much understood by the manufacturers and users.  The loss of the PS/2 mouse port on models where they are trying to save space is a no-brainer.  You don't need a mouse to configure the hardware, and the PS/2 keyboard almost always works better for that task.

RandyT

[CheffoJeffo]

Damn.  I thought the ahigh reference was funny but seeing someone kill there account is never a good thing. 

Agreed, but deleting all of your posts first is pretty damned douchy.

It also seems that his website is gone.

 

[Blanka]

The fact that they dropped the mouse and kept the keyboard should prove to the skeptics that the value of that port is still very much understood by the manufacturers and users.

The problem is that they still haven't killed the BIOS. How am I going to explain my kids Bios in 2017? Intel managed to sell its successor only to Apple. So as long as there is BIOS, there will be some PS2 around. They are Siamese twins. Kill Bios and PS2 will be dead next week.

[RayB]

LOL
If anything, people should be debating why the parallel port is still there!

[Blanka]

LOL
If anything, people should be debating why the parallel port is still there!

Read my previous post. It's there for the magnificent 12 channel USB floppy RAID.

[RandyT]

The problem is that they still haven't killed the BIOS. How am I going to explain my kids Bios in 2017?

Heh...you worry a long way into the future......by 2017,  the PC as we know it could be history and a completely new technology platform, with equally new associated interfaces could be commonplace.  The PC industry is hitting the limits of conventional technology, which is why the current trend is parallel computing.  Anything in the way of real advancement is going to take a very different shape, but speculating at what that will be and when, is a probably a bit premature at this point.

And don't forget that the millions of PC's sitting on everyone's desks won't magically disappear just because something new becomes available.  A perfect example of this is digital TV and HD.  In the US, the federal government had to legally mandate the switch.  It took years and years, and even just recently an attempt was made to extend the deadline.  MS can't even get users to upgrade their OS because there is no compelling reason to do so, and the list goes on.

Most in this hobby operate on the trailing edge, because that's where the deals are and it works for 98 percent of what one would need.  If the PS/2 port disappeared on all new motherboards tomorrow (it won't, but for the sake of discussion) the use of PS/2 controllers in MAME machines would have many, many viable years in high end machines regardless.  The "chicken little" mentality on this subject was unfounded 5 years ago, and is equally unfounded today.

RandyT

[RandyT]

If anything, people should be debating why the parallel port is still there!

Heh.  Because new PC's don't come with printers and if the consumer has one that still works, he will pass up that PC which forces him to buy a new one.

RandyT

[Turnarcades]

When it comes to interfaces we use PS/2 wherever possible. OK we use older hardware so it's not a problem, but the main reason is the simultaneous keypress restriction. Isn't it about time there was a USB 3.0 spec that did away with the 16 simultaneous limit? Plus I hate the issues with USB ID's someone described here. Considering USB was introduced to be the 'one-for-all' connection that handled all types of powered devices, it can still suffer with power issues and many OS's still have some really random issues with USB device/port assigning. At least a PS/2 keyboard connection was identifiable as just that.

[MonMotha]

When it comes to interfaces we use PS/2 wherever possible. OK we use older hardware so it's not a problem, but the main reason is the simultaneous keypress restriction. Isn't it about time there was a USB 3.0 spec that did away with the 16 simultaneous limit? Plus I hate the issues with USB ID's someone described here. Considering USB was introduced to be the 'one-for-all' connection that handled all types of powered devices, it can still suffer with power issues and many OS's still have some really random issues with USB device/port assigning. At least a PS/2 keyboard connection was identifiable as just that.

USB 3.0 largely redoes the spec, however I don't think it includes major updates to HID (which is what defines things like keyboards).

However, it is possible to make a USB keyboard that doesn't have a keypress limitation under the existing standard.  Just use variable (bitmap) data rather than array format data (or may the array length as long as the number of inputs on a keyboard encoder).  Now, this doesn't comply with the boot protocol guidelines, so the device may be unable to be used during bootup as a keyboard unless it provides boot protocol support as an alternate setting, but a USB HID compliant keyboard with no keypress limitations is certainly possible.  I've built such devices before, though they did not identify themselves as keyboards.

USB power just plain sucks.  I'll leave it at that.  I've ranted enough about the USB power situations in other topics.

As for PS/2 ports going away, they can have mine when they pry it from my cold, dead hands or provide a suitable "always works" replacement.  USB requires a fair bit of software to talk to properly since all the "brains" are in the host stack.  The PS/2 port is dead simple in both hardware and software.  I've had plenty of times when my BIOS setup program or OS (Windows, Linux, BSD, you name it) wouldn't talk USB, especially during "setup", but my trusty PS/2 keyboard always let me use my command prompt or installer just fine.

Now, for less critical input devices like joysticks, mice, or non-primary keyboards and for low-bandwidth peripherals like printers and scanners, USB is a decent option.  The HID standard is actually pretty complete without being needlessly complex, which is nice.  Just wish they would have made it peer-to-peer to begin with (like IEEE1394) rather than hacking it in later with OTG.

[csa3d]

LOL
If anything, people should be debating why the parallel port is still there!

We gotta automatically rotate our monitors some way 

-csa

[DeLuSioNal29]

Kruluk,

Best advice...  Look at the back of the computer you will be using.  If there is a PS/2 port, then go with that.  It allows for a dedicated port just for the I-pac.  Then you can plug a PS/2 keyboard directly into the I-pac.  Then you will have and extra USB port for something else.  (They get used up pretty fast).

If you have USB, then buy that version.

To "future proof" your setup is all "caca talk".  That's impossible.  Going with the logic of "future proofing" would mean that you should buy the best computer out there, so that when MAME is upgraded to later versions, it will work perfectly.  Like I said, impossible.  Eventually, newer MAME versions will come out which will require a beefier computer to run.  So a new computer will need to be purchased after all.  What makes this ANY different from the I-Pac?!?  Future proof?  I think not.

~ DeLuSioNaL

[RayB]

If anything, people should be debating why the parallel port is still there!

Heh.  Because new PC's don't come with printers and if the consumer has one that still works, he will pass up that PC which forces him to buy a new one.

RandyT

Even printers have continually upgraded their feature sets and declined in price, making it easy and desirable to just ditch the old and move to new. Case in point, the very last parallel devices I've bought was a flatbed scanner around 1998 (and a Zip drive the year before that). Eventually I got sick of the space issue and dumped the scanner and printer for an "All in one" USB device for under $100 a few years ago.  Business level users might want to keep using their big old professional printers, but those kind of users will also pay a bit more for a PC with "all the fixins".

Regarding the future, it's going to lean more and more towards a "dumb terminal" model, because 90% of the users will strictly be using it for online access, and applications themselves are moving online. The success of netbooks is a great example of where things are moving for the general mass market.

[RandyT]

Even printers have continually upgraded their feature sets and declined in price, making it easy and desirable to just ditch the old and move to new. Case in point, the very last parallel devices I've bought was a flatbed scanner around 1998 (and a Zip drive the year before that). Eventually I got sick of the space issue and dumped the scanner and printer for an "All in one" USB device for under $100 a few years ago.  Business level users might want to keep using their big old professional printers, but those kind of users will also pay a bit more for a PC with "all the fixins".

No argument there.  However, if the presence of a 50 cent addition to the circuit board is going to increase sales by even 10%, the company would be foolish not to include it.  It's marketing, plain and simple.  Also keep in mind that setting up new hardware is a walk in the park for most of the users reading this board, but Mom isn't likely to take the prospect as lightly as you might.

Regarding the future, it's going to lean more and more towards a "dumb terminal" model, because 90% of the users will strictly be using it for online access, and applications themselves are moving online. The success of netbooks is a great example of where things are moving for the general mass market.

I think your numbers are a little high.  There are still plenty of "power users" and gamers out there and the cutting edge experience is still on the PC.  If only 10% of the market used a PC for anything other than "dumb terminal" applications, you'd never be able to afford a high power 3D graphics card.

Netbook sales are high right now because they are somewhat of a novelty, and as anyone who has attempted to use the web from a cell phone knows, they can provide a much better remote web access experience without the size penalty that a full-blown laptop would inflict.  I think it would be a little naive to use their sales as an indicator that the market is running in droves toward the "cloud computing" model.  That one is still a hard sell to most I have seen express an opinion regarding it.  Most "netbook" users probably have a "real computer" they use at home.

RandyT

[richms]

The space used by the parallel header can be used for more USBs or something on the back of a atx board, which is still where most of the sales are. Once you have the 6 audio plugs, 6 USB, esata, and onboard video there is no room for a relativly massive parallel port - some have a header for it because then its just putting a header on and loads of people have the fly leads from old machines around, but even then thats still relying on chipsets still supporting it. I was under the impression that there was one chip that did most of the legacy stuff, so with no floppy, com or lpt ports, then it becomes a saving on both components, and more importatnlty board spacel

[RandyT]

The space used by the parallel header can be used for more USBs or something on the back of a atx board, which is still where most of the sales are. Once you have the 6 audio plugs, 6 USB, esata, and onboard video there is no room for a relativly massive parallel port - some have a header for it because then its just putting a header on and loads of people have the fly leads from old machines around, but even then thats still relying on chipsets still supporting it. I was under the impression that there was one chip that did most of the legacy stuff, so with no floppy, com or lpt ports, then it becomes a saving on both components, and more importatnlty board spacel

This discussion is heading off-topic, but once you have a couple of USB ports and internal headers for front panel USB connections, there's really little need to keep packing on more.  USB hubs are plentiful and cheap and more connectors just add more cost. DB-25's cost about the same as a discreet USB-B connector, so it's not like the inclusion of that particular connector is going to change the cost dynamic greatly.

Most of the legacy functionality is indeed packed into the same chip.  But there's no reason why it can't reside in the same chip where the USB implementation resides.  Added functionality costs little in the way of production.  The cost and space argument against legacy support only holds water where "cost and space" is specifically an issue, i.e. boards aimed at the "cheapest" and/or "smallest" markets. And as I stated before, consumers are still looking for these ports, so the manufacturers would be shooting themselves in the foot not to include them on everything else.  MS has been trying to kill them off for many years, but they don't sell PC's and those who do have tried and found out how much the attempt cost them when much of the inventory inevitably found its way to surplus outlets.

RandyT