A bunch of those points about ps2 are no longer accurate, it’s emulated on modern computers.
Yeah but try pressing more than 4 keys at once on the PS2 keyboard and get back to me
That is a limitation of the keyboard not PS/2. Unlike USB which is limited to 10 simultaneous key presses, PS/2 supports full n-key rollover.
USB is not limited to 10, or 6 as is sometimes stated.
This, it’s why I still use the PS2 interface. Full n-key rollover is impossible for me to do without.
I think you’re confusing USB and PS/2. USB has (or used to have?) a limit on the number of keys you could press, whereas PS/2 supports n-key rollover.
USB: Many designs and revisions, none of them perfect
Nah, USB 3.2 Gen 2x2 SuperSpeed is the best! And it took me only 30 minutes of reading articles and wiki pages to get that information! although I’m not sure what USB4 Gen 3×1 is, but it’s only x1 so can’t be that good, right?
I know this is a shitpost, but what’s interesting is that even though USB doesn’t directly interrupt the CPU it’s still faster. USB is able to get the entire packet sent before PS2 even sends one. It’s very interesting. So if you ever see anyone unironically saying there is less latency call them out!
Are PS/2 ports still operating on hardware interrupts these days? I would expect these to be emulated as USB devices at this point, depending on whatever I/O chipset is in play.
The bit about USB asking the CPU is kinda true? My understanding is that it’s a packet protocol of sorts, so it’s really just writing post-it notes for each button press and leaves them on the CPU’s whiteboard for later.
I haven’t seen a device with those in a very long time.
Same as VGA, shit just works, don’t need to worry about drivers or OS. So if your server shits the bed, you don’t need to worry about these things not working so you can can figure what went wrong.
In a server environment it’s perfect. Have multiple baremetal servers in the rack?
No problem, all you need is a PS/2 + VGA KVM and you can control them easily without fiddling. No protocol handshake, no HDCP in the way.
I don’t know what server you’re running, but I have never had any issues with USB keyboards. They just work, including in the firmware. No drivers needed. Besides, a proper server motherboard will have IPMI so you can just remote into it.
I’ve had KVMs that don’t like the ‘fancier’ USB keyboards with NKRO. It would work, but it wouldn’t listen for its own ‘switch to different console’ hotkeys. Reconfiguring the keyboard to run in 6KRO-only mode addressed it, but not every keyboard can be configured that way.
For most workflows, especially text, 720p is more than enough.
That said, DisplayPort >>>>> HDMI
If there is a fault in the PS2 device it literally breaks the rest of the computer.
A little more than 15 years ago I had to fix my PS2 keyboard because it crashed everything. Not even a BSOD, just colors.
looks nervously at my 3070ti and ibm model m haha so was there any permanent damage or like
No. It was when I was younger and I smacked the keyboard at some point. The whole computer crashed with random pixels all over the screen. I tried rebooting many times. I came to the conclusion the cable inside of the keyboard must have been slightly disconnected and pushed it further back into it, and my PC worked again.
Computers are really resilient to permanent damage to be honest. I once dropped a screw into a running computer and it short-circuited with sparks and all. I was still able to boot it, but it was extremely slow. After a few reboots it was back to normal.
Your story reminded me of when I set my pc on fire!
No idea how or what happened but the PSU shot sparks, lit up and tried setting the house on fire. Amazingly everything worked right after replacing the PSU, but the Mobo was the next thing to blow up.
So while they are indeed resilient af, you’re likely not coming out unscathed if sparks fly.
If there is a fault in the PS2 device it literally breaks the rest of the computer.
That must be OS dependent
My keyboard uses PS/2 and although I do have a PS/2 to USB adapter, i prefer using my computers PS/2 port because it means one more USB port can be used for something else.
30+ years old and it runs flawlessly.
Isn’t almost any keyboard able to last that long?
I make sure any motherboard I buy has at least 8 USB ports, so I know I’ll have enough. It does make sense to use the PS/2 port if you have the peripherals. What advantage does USB have over it anyway?
I go through a cheap Logitech keyboard just about once every three years. I replace them when a a couple of keys stop working or when the nubs wear off of the center keys and can no longer blindly find where my hands go.
Isn’t almost any keyboard able to last that long?
In theory, yes. In reality… not so much. Bluetooth keyboards are a joke for longevity, and a lot of wired keyboards these days just have piss poor build quality.
I don’t think PS/2 inherently has major advantages over USB but as someone who uses a small PC with few USB ports, I appreciate having a PS/2 port available.
Usb keyboards can have n-key rollover which let’s you press more buttons simultaneously, whereas PS2 has a hard limit of like 5 or so
Refer to below comment
It’s actually the other way around. Check out Ben Eater’s awesome videos for technical details.
TLDR: PS/2 sends separate key up and key down events, sequentially - like - - - - each in separate message, allowing for theoretically infinite rollover (excluding certain edge-cases). USB, on the other hand, polls only for keys being pressed at the moment. By default, the keyboard responds with a 8-byte message, with 1 byte being the bitmask for 8 modifier keys (4 on each side), a spacer, and 6 bytes/slots for identifiers of keys being held down. If one identifier is present in one response but is missing or replaced in next one, the system assumes a key-up event. It is possible by USB spec to negotiate connection in such a way that the keyboard responds with a bitmask for every single key it has. But this is not well supported by things like BIOS and KVM’s, so very few keyboard manufacturers bother implementing it. Most keyboarrds advertising NKRO are actually only capable of doing so via the PS/2 adapter.
I’ve often thought this about older or less generally useful ports, but then it just keeps coming back to the fact that, if I had the same number of spare ports, plus one more USB that I useD for this keyboard instead of a dedicated PS2 or an old USB 2, I’d be in the same situation but with at least one more useful and fast USB that maybe I might for some reason want to use without my wired keyboard plugged in.
It makes sense in terms of cost, because the older more narrowly useful port is hopefully cheaper, but otherwise it’s just unnecessary and more limiting than the same overall number of ports where all of them are the most widely useful and fastest possible throughput.
