3 ms·

I am somewhat curious as to how this is greatly different than QEMU?

by walrus01 4y ago

rahen 4y ago
Or Bochs, more specifically. Qemu is a frontend to various CPU emulators and hypervisors (KVM, NVMM, HAXM etc.).
- perbu 4y ago
  Qemu is a lot more than just a frontend. It contains both CPU emulation code and machine emulation code in addition to being able to leverage Linux as the hypervisor. It is a massive piece of software.
  - rahen 4y ago
    Of course. I didn't imply the various backends and operating mode of Qemu weren't part of the set. I meant that Bochs and 86box are just single commands that do a single thing. Qemu is more like LLVM and is indeed massively more complex.
- anthk 4y ago
  Qemu has a TCG accel. module.
- gattilorenz 4y ago
  Neither Bochs nor QEMU emulate a vast set of specific hardware (such as motherboards, CPUs, video, SCSI, sound and network cards) from the 90s. With 86box I managed to install and run, for example, a version of SCO Unix that only supports a very limited number of SCSI adapters and VGA cards: https://virtuallyfun.com/2021/07/13/installing-sco-unix-part-1/ https://virtuallyfun.com/2021/07/13/installing-sco-unix-part...
  - rahen 4y ago
    Interesting. This could interest a project like NetBSD for automated regression testing on old hardware.
    - gattilorenz 4y ago
      I guess it might help a bit, but the emulation is not 100% accurate, and I suspect the greatest challenges for NetBSD are anyway coming from non-x86 obsolete hardware like Vax, Amigas and the likes.
haspok 4y ago
There is this excellent FAQ page that answers your question: https://86box.readthedocs.io/en/latest/usage/faq.html https://86box.readthedocs.io/en/latest/usage/faq.html
nubinetwork 4y ago
QEMU will let you emulate a particular cpu family, but you can't really tell it that you want a "486dx2 66 with 256kb of l2 cache". While 86box/pcem can't get 100% accurate, it's a lot closer than QEMU emulating the cpu family at your host cpu's full speed (or as close as QEMU can get with a single thread of opcode translation in the case of running other arches like ppc/hppa/sparc on a x64 host).

I am somewhat curious as to how this is greatly different than QEMU?

rahen 4y ago

Or Bochs, more specifically. Qemu is a frontend to various CPU emulators and hypervisors (KVM, NVMM, HAXM etc.).

perbu 4y ago
Qemu is a lot more than just a frontend. It contains both CPU emulation code and machine emulation code in addition to being able to leverage Linux as the hypervisor. It is a massive piece of software.
- rahen 4y ago
  Of course. I didn't imply the various backends and operating mode of Qemu weren't part of the set. I meant that Bochs and 86box are just single commands that do a single thing. Qemu is more like LLVM and is indeed massively more complex.
anthk 4y ago
Qemu has a TCG accel. module.
gattilorenz 4y ago
Neither Bochs nor QEMU emulate a vast set of specific hardware (such as motherboards, CPUs, video, SCSI, sound and network cards) from the 90s. With 86box I managed to install and run, for example, a version of SCO Unix that only supports a very limited number of SCSI adapters and VGA cards: https://virtuallyfun.com/2021/07/13/installing-sco-unix-part-1/ https://virtuallyfun.com/2021/07/13/installing-sco-unix-part...
- rahen 4y ago
  Interesting. This could interest a project like NetBSD for automated regression testing on old hardware.
  - gattilorenz 4y ago
    I guess it might help a bit, but the emulation is not 100% accurate, and I suspect the greatest challenges for NetBSD are anyway coming from non-x86 obsolete hardware like Vax, Amigas and the likes.

haspok 4y ago

There is this excellent FAQ page that answers your question: https://86box.readthedocs.io/en/latest/usage/faq.html https://86box.readthedocs.io/en/latest/usage/faq.html

nubinetwork 4y ago

QEMU will let you emulate a particular cpu family, but you can't really tell it that you want a "486dx2 66 with 256kb of l2 cache". While 86box/pcem can't get 100% accurate, it's a lot closer than QEMU emulating the cpu family at your host cpu's full speed (or as close as QEMU can get with a single thread of opcode translation in the case of running other arches like ppc/hppa/sparc on a x64 host).