OS/2 is older than that, but since ArcaOS is being made available nowadays, I think it's fair that it should current monitors of the day. I don't know how you get to decide what's more important. This is pretty damn important to me.
OS/2 development ceased around 1996. It would be really nice, to support "monitors of the day". In fact, it is amazing how well monitors that are not too old, are supported, considering that ONE guy does most of that, along with USB 3, WiFi, wired NIC drivers (MultiMac), AHCI, ACPI, and a lot of other things. If you are capable of writing, or modifying, video drivers, I am sure that Arca Noae would welcome the help. If not, you can wait for it, with the rest of us. We need USB3, then WiFi, UEFI, GPT disk support, and a dozen other things, before we need higher resolution screens. I hear that USB 3 is getting closer, but it doesn't exist, until it is announced.
Yes, actually, I have played around with guest and with installers, and ACPI, and never had any luck getting more than 1 CPU to show.
Show where? In the VBox settings, or in the guest? If in the guest, does it have the SMP kernel installed? The SMP kernel works fine, in one CPU, and
*may* load if you define 2 CPUs, but it still doesn't work very well, if at all, in a VBox with more than 1 CPU defined. The UNI kernel will only run 1 CPU. The setting in VBox should be obvious.
Any specifics as to which settings you changed that improved results ? One thing I found is that using Intel HD audio for the emulated sound device is much better. AC 97 caused sounds to break down early. Even the startup system sounds are cut off.
The best sound device is SB16 (even with win XP as a guest, I use SB 16 - newer versions of windows won't support SB 16). More advanced devices will cause sound break up. That has always been the case in VBox. The startup sound is often cut off, it is best to eliminate that all together.
The most important settings are:
Use SATA with AHCI for disk access, also check the box that says SSD, AFTER you get it working with SATA and AHCI, (The default Virtual Machine installer settings do not support that, use the full ACPI setting). If converting, add the OS2AHCI driver, before deleting the DaniS506 driver, and changing the virtual controller settings. Add the parameters "/n /f" (without the quotes) to the OS2AHCI driver, AFTER you get it working (just like in a real machine).
Use enough memory that it never needs to swap (1536 MB is usually adequate). It cannot be more than about 3.5 GB.
Enable I/O APIC, before you install. This probably needs ACPI.
Set Paravirtualization to Default, and enable VT-x/AMD-v and Enable Nested Paging.
Video has been discussed. I never enable 2D, or 3D, support. I doubt if either one actually does anything in OS/2. There are some new settings for Graphics Controller. I haven't tried them, yet.
Audio: as mentioned above, use SB 16, and the PNP driver.
USB: select USB 2.0, until we have a USB 3 driver.
Shared folders has been enabled (in the guest) recently, in two ways. Start without that, to prevent confusion. So far, I haven't got around to trying either one seriously, and I have heard comments that neither one actually works 100%.