2Dave Yeo: Yes, good note! Modern videocards have too much on-board RAM. Mine, for example has 256 MB (it is Radeon 9600 XT), so I decreased memory mapping to 16 MB in SNAP, which is sufficient for 2D acceleration and my FullHD screen to work. This will greatly economize the kernel address space. The key for VBox to work is to get more available address space to userland (hence, increase VAL to 3072). But increasing VAL requires decreasing JFS cache, if it is too much, and THREADS (to e.g., 511)/PROCESSES (to e.g., 128). Also, you need to control how much free space remained in the kernel arena, with Theseus (see the end of System->Kernel Information->Kernel Memory usage report):
allocated committed present resident Totals
-------- -------- -------- --------
38133000 12D93000 12D15000 111E3000 Total (in bytes)
918732 308812 308308 280460 Total (in Kbytes)
897.199 301.574 301.082 273.887 Total (in Mbytes)
< End of THESEUS4 (v 4.001.00) output @ 3:01:58 on 15/4/2018 >
You can see that here is 897.199 of 1024 MB is occupied. So, 100+ MB is free, which is sufficient. I have VAL=3072, PROCESSES=156, THREADS=511, and JFS cache set to 128 MB explicitly:
VIRTUALADDRESSLIMIT=3072
EARLYMEMINIT=TRUE
DLLBASING=OFF
PROCESSES=156
THREADS=511
ifs=d:\os2\jfs.ifs /autocheck:* /cache:128000 /lazy:8,60,5 /p1
PS: Also, you can try to decrease Video memory used by your video card in BIOS, if you have such setting (in case you have an integrated video card).
2Dariusz Piatkowski: Documentation is good enough, at least, most needed configuration options are described ok. You can ask develpers, if in troubles, they are on this forum and on IRC.
Installation is simple, as any other OS/2 kernel. You have to copy kernel and os2ldr instead IBM's ones, or install QSINIT, which is better to use. Both QSINIT and OS/4 os2ldr support multibooting several kernels. (But there is a number of drivers supplied with the kernel, which should be copied to \os2\boot. These drivers have no name conflicts with existing drivers. AlexT wrote a short HOWTO for quick setup, which is included in latest kernels. Also, there is doscalls1.dll which is optional. It is compatible with IBM's version). Also, there is a multibooting feature of OS/4 os2ldr (and QSINIT works the same time, I use it). So, you can boot multiple kernels from the os2ldr menu (it is better described in QSINIT documentation). Also, OS/4 has built-in CONFIG.SYS editor (activated with Alt-E in loader menu), which is handy if you need to REM out or add something temporarily. It has a good logging feature (a central system log, available for reading via a COM port, or via "copy KERNLOG$ kernlog.txt" after the system booted successfully). Very handy for developers, to debug drivers. Also, there are some enhancements, like hi-res HPET timer support (no hi-res timer bug in apps like Mozilla, like ACPI.PSD has), support for CPU rendez-vous (running the code on all CPU's in parallel), which is used in VBox for VT-x/AMD-V support etc., etc.
Regarding ACPI, yes, OS/4 devs got boring patching each time every new version of ACPI.PSD, so they gave up. But they created their own ACPI module (which is not yet released, it is available for testers, and those who is not too lazy to debug it to make it working, with devs' help). So, ACPI.PSD should be not a problem too.