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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/28/26 22:20, Jari Ruusu wrote: > With CONFIG_X86_LEGACY_VM86=y set in 32-bit Linux kernel, > currently running linux-6.12.91, one memory+CPU intensive > operation in DOS version of WordPerfect takes less than 0.5 > seconds. With CONFIG_X86_LEGACY_VM86 not set, same operation > takes about 2 seconds. Just out of curiosity, what operation is that? How often do you do that operation in a day or a month? >> I'm also curious why modern virtualization hardware >> doesn't help either. > > My current setup uses virtualization: > > 64-bit x86 host + 64-bit Linux kernel/distro + Qemu/KVM > --> boots 32-bit Linux kernel/distro ( X86_LEGACY_VM86=y ) > --> boots dosemu + FreeDOS > --> runs DOS version of WordPerfect Just like Brian asked, I'm confused why this needs the 32-bit Linux distro in the mix. But, if I were you, I'd just keep the 32-bit distro image around, off the Internet, and never update it. Just like the version of DOS you have and WordPerfect. The 32-bit distro doesn't need a mainline kernel. It just gets frozen in place with a 2026 kernel, just like your 1994 version of WordPerfect and DOS are frozen. As I'm sure you know, that 32-bit distro is getting harder and harder to keep updated. I've jumped around distros for 32-bit testing a few times in the last decade as folks retired their 32-bit x86 ports. With Debian gone, I'd expect its derivatives to die off in the next few years, making this whole thing even harder.