Whats the point of USB mice/keyboards?

[Roots]

Keyboards and mice are output devices (not I/O). As far as I know they don't receive any input from other portions of the computer other than maybe signals to verify the existance of the device. So why are so many companies making their mice and keyboards USB? USB is high speed, and I think that one shouldn't waste their USB ports with simple devices that already have a PS/2 port neatly placed for them that works just fine. The only reason I can think of to have a USB keyboard is if there are additional USB ports on the back so you can hook up your USB mouse/game controller/whatever to the keyboard rather than the back of the PC.

And yes, I know there exist converters from USB to PS/2. I just don't understand what the big deal is. One of my friends was saying that you MUST have a USB keyboard/mouse (for popularity purposes); It just doesn't make any sense to me.

 

[stevewm]

USB, since its design, was meant to replace the several low-bandwidth I/O ports (Serial, Parallel, Game, and PS/2) presently in PCs. The high speed extension to USB, USB 2.0; was just a logical upgrade to USB. USB 2.0 gives USB more flexibility as you can connect higher speed devices, such as network cards and soundcards that would normally require a internal ISA or PCI slot....

Consolidating all those into one port is a move to make things a bit simpler, going all USB also gives mobo manufactuers more room on the PCB to add more features. And it allows for even smaller form factor PCs.

Just as DDR RAM replaced SDR, and just as SerialATA will eventually replace Parallel ATA; USB will eventually replace all your low bandwidth I/O ports. Though the latter 2 will occur very slowly over the next few years.

 

[Thor86]

When USB first came out, it was slow as hell on older/slower systems. Nowadays, no problems with USB peripherials, but I still use PS2 for keyboard/mouse personally.

 

[igowerf]

Well, I know that with PS/2, you're not supposed to just yank out or plug-in devices while your system is on. With USB though, you're allowed to do that. I think the main reason for all the USB keyboards and mice is just marketing. At least when PS/2 gets phased out, we'll have plenty of USB keyboards and mice on the market.

 

[Peter]

The big goal is to get rid of the ancient keyboard controller (an ancient 8-bit ISA bus device designed back in 1977). The plan for legacy-free PCs is to have USB replace all the low speed I/O (serial, parallel, keyboard, mouse, floppy). The benefits of course are elimination of the Super-IO chip and the ISA bus altogether (even its low pin count "LPC" implementation currently used on mainboards); and of course having a pile of multipurpose USB ports instead of a handful of single-purpose dedicated ports.

 

[eklass]

it's for diptars who like to have problems

i neve rhave problems with a ps2 mouse, but consantly run into issues with usb mice

now... if i decide to get a wireless keyboard mouse combo (as opposed to my wireless mouse and wireless keyboard) that has 1 RF transmitter that plugs into a USB port, i may opt for usb then

 

[scythe4ever]

Personally USB might turnout to be a good option in the next year or so, but at the moment i find my ps2's sufficent, other than that Igowerf my ps2 mouse or keyboard work perfectly even if i yank them out and plug it back in while my system is on.
Take care
Scythe

 

[Peter]

You wouldn't be the first to zap the port on the mainboard. None of the legacy ports are made for hot plugging. That'd require sequenced contacts, frame ground first, then power, then I/O lines - as seen on USB.

 

[igowerf]

Originally posted by: scythe4ever
Personally USB might turnout to be a good option in the next year or so, but at the moment i find my ps2's sufficent, other than that Igowerf my ps2 mouse or keyboard work perfectly even if i yank them out and plug it back in while my system is on.
Take care
Scythe

Chances are, you wouldn't run into problems yanking out your PS/2 devices. I used to do it a lot with my keyboard. There have been stories of people killing their PS/2 ports from doing that though. I suppose new motherboards can handle it.

 

[Peter]

Unplugging isn't nearly as dangerous as plugging. From electrostatic discharge over blown power fuses to frying chips because the actual I/O pins get connected before the chip gets power, there are plenty of ways of toasting something expensive.

 

[HappyCracker]

HA! Toasted my onboard keyboard on my lappy pulling out an external ps2 keyboard. i learned my lesson. Still use ps2 for keyboard and mouse, but I'm a lot more cautious

 

[corkyg]

Originally posted by: Roots
Keyboards and mice are output devices (not I/O).

Not exactly correct. A keyboard and mouse are classiffied as INPUT devices in the world of peripherals. They input scan codes from the user to the computer.

USB has some advantages - primarily the ability to be hot plugged and unplugged. PS/2 ports can't do that. And, unless your mobo supports USB in DOS, you can't have any mouse support in DOS with USB devices. My mobo is fairly new (Asus P4PE) and it will not allow USB to be active in a DOS boot situation such as HDD cloning.

So, I use both. My keyboard and mouse are USB - my Wacom digitizing pad is USB. It works for me.

 

[WannaFly]

Originally posted by: Roots
Keyboards and mice are output devices (not I/O). As far as I know they don't receive any input from other portions of the computer other than maybe signals to verify the existance of the device. So why are so many companies making their mice and keyboards USB? USB is high speed, and I think that one shouldn't waste their USB ports with simple devices that already have a PS/2 port neatly placed for them that works just fine. The only reason I can think of to have a USB keyboard is if there are additional USB ports on the back so you can hook up your USB mouse/game controller/whatever to the keyboard rather than the back of the PC.

And yes, I know there exist converters from USB to PS/2. I just don't understand what the big deal is. One of my friends was saying that you MUST have a USB keyboard/mouse (for popularity purposes); It just doesn't make any sense to me.

As stated above, You must've failed intro to computers 101 . Ok, mice and keyboards are input devices, not output. I love and only purchase usb keyboards/mice just because i like the idea of being able to unplug them and connect them to another computer without harm. With the number of USB ports on computers now adays, why not? Also, i think i read something on how some of the high resolution HAVE to use USB for the data rate.

my .02

 

[beatle]

What about the maximum 125hz refresh rate on the usb bus as opposed to 200hz for ps2? I use ps2 mice specifically for this reason.

 

[Zepper]

For victims of the government school system who no longer have the capacity or attention span to figure out which jack to plug kbd/mse into. Nor are they able to RTFM...
.bh.
:beer: time!

 

[stevewm]

Originally posted by: beatle
What about the maximum 125hz refresh rate on the usb bus as opposed to 200hz for ps2? I use ps2 mice specifically for this reason.

Its not so much a "refresh" rate......

USB input devices are polled by the USB Host 125 times per second. PS/2 devices can be polled anywhere from 20 to 200 times per second. While technically PS/2 should be "smoother" I doubt you'll find anyone who can tell a difference!

Do a double-blind test on yourself. Have someone switch your mouse between USB and PS/2 without you knowing which port they switched to (or if they switched it at all!). I doubt you'll see ANY difference between them.

 

[Peter]

You're not going to like the system bus load imposed by polling the legacy keyboard/mouse controller that often. Again, this is an 8-bit ISA device, the I/O sequences to access this take ages.

Besides, mice aren't polled at all to begin with. It's all interrupt triggered, everything else would be extremely stupid.
That adjustable rate thing manipulates how often per second the device sends a data packet. More packets don't give smoother movement; the only thing affected is that with slow rates and really fast and wide movements, users can manage to exceed the numeric range that describes a movement. E.g. when you move the mouse really fast and the cursor goes backwards or stands still, it's time for a faster packet rate. On USB this is practically impossible anyhow, on PS2 you'll have to find a balance between mouse usability and how much system load you want to invest.

So actually, the adjustable packet rate on PS2 isn't a feature to brag about, it's rather a necessity to overcome the limitations of that connection. It isn't missing on USB, it's just a kludge that's not needed there.