Why do modern motherboards still have PS\2 connectors these days ?

[William Gaatjes]

I noticed that even today this still seems to be standard.
Is there a special reason for this ?
Seems like a bit outdated.

 

[IntelUser2000]

Most newer boards don't, but some low power and cheaper ones do like this one: http://asrock.com/mb/Intel/J5005-ITX/index.asp

That's a motherboard based on a brand-spanking-new Pentium Silver J5005, but has PS/2 ports for mouse and keyboard. I've read about it, and it has to do with compatibility with certain Operating Systems, and the fact that legacy systems are more likely to work with devices without having to download the latest drivers. PS/2 has other advantages over USB too. This thread describes it well: https://linustechtips.com/main/topic/395531-why-do-modern-motherboards-still-have-ps2/

 

[Mr Evil]

...PS/2 has other advantages over USB too. This thread describes it well: https://linustechtips.com/main/topic/395531-why-do-modern-motherboards-still-have-ps2/

That thead mentions n-key rollover a lot, but I have a USB keyboard with n-key rollover right here.

 

[mikeymikec]

I've been buying mid-range boards regularly for nearly 20 years and the number of PS/2 ports seem to have gone from 2 to 1 to 0 and back up to one or two. I think for a while the logic was that all things die regularly and so therefore going to newer technology ports made more sense, but actually it's perfectly feasible to still be using a PS/2 keyboard. My own personal keyboard is pre 21st Century, and I plugged in a keyboard from a PC running Windows 95 in 2018 into a new computer for a customer. It works. Why throw it out?

 

[Midwayman]

My own personal keyboard is pre 21st Century, and I plugged in a keyboard from a PC running Windows 95 in 2018 into a new computer for a customer. It works. Why throw it out?

Especially so with mechanical keyboards. A lot of those from the 80's are still good.

 

[rameshrr3]

I use PS/2 keyboards so i dont have to occupy the usefulness of USB slots. A big reason why PS/2 is still used ( in new business desktops and workstations) is simply put Corporate IT Security. A lot of companies simply disable all USB ports to end users to avoid the many security risks(data theft, virus and malware injection etc), that leaves a 'hapless' user with only the reliable but relatively secure PS2 port for Keyboard and Mouse. Stuxnet showed how dangerous stray or unknown USB devices are as they caused Centrifuges to spin out of control. Disabling USB ports for all non IT Admin users secures the IT corporate infrastructure by reducing available Attack surface area. Gaming desktops or home use desktops by contrast don't usually come with inbuilt PS/2.

 

[NTMBK]

Ain't broke don't fix it. There's plenty of spare room on a modern motherboard back panel- no big printer port or serial port eating up most of a row. And what are you going to put in its place, another two USB ports to go with the existing 8 ports?

It's a good connector which gives slightly better keyboard performance than USB, and keeps great old keyboards in action. Long live the PS/2 port!

 

[mv2devnull]

I have at least one motherboard, where "Optimized defaults" loads OS before USB keyboard is active. In other words, I can't access UEFI unless I have a keyboard on PS/2.

Is there a reason? I don't know, but I'm happy that the board does have that PS/2.

 

[Iron Woode]

the GA-Z270N WIFI I used in an HTPC build had PS/2.

 

[Charlie22911]

IIRC a lot of high end boards have them too since extreme overclocking can make some peripheral busses act a bit wonky.

In fact both my x99 Godlike Carbon and x299 TaiChi XE have them.

 

[DigDog]

Most hardcore eSports players still prefer ps/2, so it's not just legacy, it's actually being used today.

Dont get me wrong, it's not like you lose some "things were better in my days" obscure functionality if you go with usb (specially with 1ms polling), but it's still totally functional.

Tbh putting usb connections on devices which dont need usb is just some silly craze that happened when usb1 was the new thing.

 

[hojnikb]

SuperIO chips, used on motherboards still have ps/2 support, so it really costs just a few cents more for the manufacturer to add ps/2 support

 

[tcsenter]

There are LOT of examples where a firmware/BIOS update or CMOS reset will render USB keyboard unuseable to enter SETUP/BIOS or early boot menus (until a complete reboot), whereas the PS/2 just works. At least, there were five or six years ago.

 

[Charlie22911]

There are LOT of examples where a firmware/BIOS update or CMOS reset will render USB keyboard unuseable to enter SETUP/BIOS or early boot menus (until a complete reboot), whereas the PS/2 just works. At least, there were five or six years ago.

That actually reminds me, many “fast boot” options will skip enumeration of USB devices to speed up the boot process. It’s a bit niche, but PS/2 would be handy in that case as well.

 

[DontMessWithJohan]

Loads of people still use ps/2 keyboards and will probably for a while to come. The cheap ones are made to last. Plus you can make the argument that the port is still more reliable than USB, which is pretty shameful.

 

[Oyeve]

My latest MSI 360 Gaming Plus board came with one and I am glad it did. Never know when your USB ports go south and you need to get into the BIOS.

 

[mikeymikec]

I have at least one motherboard, where "Optimized defaults" loads OS before USB keyboard is active. In other words, I can't access UEFI unless I have a keyboard on PS/2.

Is there a reason? I don't know, but I'm happy that the board does have that PS/2.

For many years I think USB was still considered not quite mature and so therefore a potential liability hence that option, but I'm a bit surprised to hear of a board that must be 2011-2012 at least that till has that option disabled by default. Having said that I continued putting floppy drives into my PC builds until about 2010 IIRC ('just in case' thinking) and mainly stopped because my main supplier stopped selling them (at least for a while).

 

[mopardude87]

I remember getting this Q6600+MOBO combo at Frys and well going home being so hyped then my heart sank when i noticed ide+ps/2 all were gone. Good times freaking out rushing a return cause honestly my budget was blown and i had a ide hard drive and ps/2 mouse and keyboard lol. I think it was the G31? i thought it was just ECS being super cheap on the motherboard as usual till i found out it was the chipset.Oh the joy i ranted for quite a bit. Good motherboard though,a stock voltage oc warrantied all the usb ports to stop working. Always a good adventure with the ECS and MSI motherboards in those days.

Kind of fun to see over the years the disappearance and return of the ps/2 ports.My current Z370 has both ports wow. Yeah look out my i5 8400+ 1070ti destroys all my games at 1440p yet here i see those ps/2 that my little ECS El cheapo board back in 2008 just could not offer.

 

[fastamdman]

Because usb sucks under LN2

 

[diettweak]

The USB protocol limits the n-key rollover to a maximum of 6 meaning if you play a game that uses tons of buttons after 6 keys you start missing keys no matter how good your board is PS/2 allows full n-key rollover if your board supports it

 

[William Gaatjes]

The USB protocol limits the n-key rollover to a maximum of 6 meaning if you play a game that uses tons of buttons after 6 keys you start missing keys no matter how good your board is PS/2 allows full n-key rollover if your board supports it

That is interesting.
Did not know about that.
A quick search for HID and n key roll over made me visit the wiki page.
Indeed.

https://en.wikipedia.org/wiki/USB_human_interface_device_class

https://en.wikipedia.org/wiki/Rollover_(key)

I tested it out by pressing either 6 or more keys (by pressing 2 keys with each finger using 8 fingers) at once on my keyboard in notepad. I am indeed limited to 6 characters at once.
My system runs in boot mode.
But for me that is sufficient.

I do wonder, how do you press more keys at the same time willingly ?
By using some configurable macro key generator function embedded in your keyboard i would think.
Can some typists type that fast that they can hit more than 6 keys( + 2 modifiers ) at once ?

 

[William Gaatjes]

I use PS/2 keyboards so i dont have to occupy the usefulness of USB slots. A big reason why PS/2 is still used ( in new business desktops and workstations) is simply put Corporate IT Security. A lot of companies simply disable all USB ports to end users to avoid the many security risks(data theft, virus and malware injection etc), that leaves a 'hapless' user with only the reliable but relatively secure PS2 port for Keyboard and Mouse. Stuxnet showed how dangerous stray or unknown USB devices are as they caused Centrifuges to spin out of control. Disabling USB ports for all non IT Admin users secures the IT corporate infrastructure by reducing available Attack surface area. Gaming desktops or home use desktops by contrast don't usually come with inbuilt PS/2.

I remembered stuxnet.
Access with a usb flash drive.
But is that not easily solvable by setting up the windows group policy correctly for windows to deny any usb flash drive.
I would expect that a company would have a good IT department that has proper group policy settings set up.
Of course that would only work with the professional windows. Not windows home, which should not be used in a company.

 

[lopri]

Most newer boards don't, but some low power and cheaper ones do like this one: http://asrock.com/mb/Intel/J5005-ITX/index.asp

That's a motherboard based on a brand-spanking-new Pentium Silver J5005, but has PS/2 ports for mouse and keyboard. I've read about it, and it has to do with compatibility with certain Operating Systems, and the fact that legacy systems are more likely to work with devices without having to download the latest drivers. PS/2 has other advantages over USB too. This thread describes it well: https://linustechtips.com/main/topic/395531-why-do-modern-motherboards-still-have-ps2/

Bingo. Older OSes do not come equipped drivers for new USB controllers. So in such circumstances legacy connection is necessary. Case in point, try installing Windows 7 on new Ryzen platform without PS/2 keyboard.

 

[BurnItDwn]

I am annoyed by all the boards that are missing the PS/2 ports.
It's annoying to have to find adapters

 

[beginner99]

I am annoyed by all the boards that are missing the PS/2 ports.
It's annoying to have to find adapters

Can you even still buy such keyboards /mice? I mean keyboards and mice in my world have a pretty limited life-span og couple years beyond which even with regular cleaning they tend to get too disgusting to use. Can't imagine usig a 20 year old PS2 keyboard. eeewwwh.