Late to the party regarding this, but there is a lot of misinformation being stated.
USB and PS2 protocols are COMPLETELY different from each other -- barely even in the same universe. You can't "convert" from one to the other. You can talk to the mouse hardware with one protocol and then virtualize the other to the software, but you can't just plug PS2 wires into a USB port (or vice versa) by moving wires around and expect it to work. The first mice used regular serial ports (RS-232) or a special card that plugged into the spare slots that old computers had lots of (these were called bus mice). After that came the PS2 mice, which pretty much became the standard before USB was developed. When USB was just starting out, there were mice being made that understood INTERNALLY both PS2 and USB protocols and came with a simple wiring adapter. Those particular mice understood both PS2 and USB protocols, automatically detected which kind of port they were plugged into, and selected the correct internal parts to do what they needed. AFAIK those USB/PS2 "dual-mode" mice aren't being made any more, but they were popular for awhile. I think you can also still get adapters that will let you plug PS2 mice and/or keyboards into modern computers that only have USB ports, but those are much more than simple wiring adapters. There is a "block" in the middle of the cable which has a bunch of hardware and software/firmware in it that talks in two different directions with two different protocols and does the necessary buffering/translation/virtualization so the the computer believes it is talking to a USB mouse when it actually isn't. When USB was first being contemplated, one of the main goals of computer design efforts was to move everything up into the Operating System so that a BIOS was no longer needed. That goal has now essentially been achieved with modern UEFI systems that don't even have a BIOS any more. The problem with that idea was that you still need a keyboard and/or a mouse when the computer first boots up (before the Operating System even loads) so you can do things like change BIOS or UEFI settings. You also need a keyboard and/or mouse in older Operating Systems (like DOS) that were developed way before USB was created (though computer manufacturers don't care very much about that any more). The USB protocol is WAY more complicated than the PS2 protocol and they couldn't expect the BIOS manufacturers to provide USB support directly (after all, the intent was to move USB support up to the Operating System and not even have a BIOS). So they needed to come up with a way to virtualize a PS2 mouse from USB before the Operating System is loaded. This virtualization can't just occur in software, but must also be assisted by the hardware (PS2 is a hardware protocol, not a software protocol). The hardware portion of the virtualization is provided by a combination of the USB host controller, special capabilities of the PCI bus, and a special operating mode of the CPU called System Management Mode (SMM). The whole process is really a giant, complicated kludge, but was one of the first steps necessary for the ultimate elimination of the BIOS. This is a complicated subject and I can go on for awhile longer about details if anybody cares -- some if it is already discussed in the documentation provided for my USB drivers. Bottom line, though, is that you CAN'T just interchange PS2 and USB mice with wiring adapters and expect everything to work out just fine. In some cases it will, but in most cases it will not. ____________________________________________________________ Urgent Alert: Doing This In The Shower Destroys Testosterone pro.healthresponses.org http://thirdpartyoffers.juno.com/TGL3141/5d544f1d6c3a44f1d37b6st03vuc _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
