Now this reminds me of “turning the engine off and then back on again at 55 mph.”

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the v86-64 patch, Allows you to enter v86 mode from long mode on a 64bit linux kernel.

Basically it works just like an old school DOS Extender, where it’ll switch from long mode, to 32bit compatible mode, then enter v86 mode run some code, then re-enter 32bit mode, to jump back into 64bit long mode.

From an old mailing list:

PERFORMANCE
This 64-bit DOSEMU compile runs substantially slower than the 32-bit compile
that I used previously on this computer.  I have several rather large
PowerBASIC/DOS programs that are, in fact, the main reason why I use DOSEMU.

Up until a couple of days ago, I had Fedora 7/i386 on this computer.  I just
happen to still have the numbers when compiling one of those programs with
PowerBASIC/DOS under DOSEMU:

With F7/i386:  1686600 lines per minute -- total time to compile the program:
0.2 seconds

With F8/x86_64:  230400 lines per minute -- total time to compile the program:
1.6 seconds.

The F8/x86_64 DOSEMU is running approximately 13 times slower.

Which I bet runs a bit faster than an old 386.

2 thoughts on “Now this reminds me of “turning the engine off and then back on again at 55 mph.””

  1. This reminds me of:
    Here in Germany you can buy 2 or 4 stroke scooters limited to 25kmh. In fact their engines would do 50 or even 80kmh. The electronic ignition just turns off your motor at 25kmh. A second later you are at 24kmh. The motor turns on again.
    Sounds horrible when such a thin comes along the street 🙂

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