Comment by cmrdporcupine
4 hours ago
You don't build the networking or filesystem by hand every time you need them. You pull them from reviewed and maintained library code from a repository. That's how MirageOS etc work. Someone else has written e.g. TCP/IP -- hopefully well -- and you link against it.
The point that makes this different from an OS is that there's no shared service, no syscalls to do that stuff -- just subroutine calls -- and no timesharing (except at the hypervisor level). It's just a single runtime running on hypervisor direct against the virtualized hardware.
Because, yeah, all this work has happened in hardware in the last 30 years to make that possible, but we still treat the operating system as the best unit of resource sharing. When in fact it's kind of a jack of all trades master of none. If you're booting a whole linux kernel -- with its giant framework built to co-tenant a pile of applications and users -- just to run one process, there's definitely something to look at there. Even if the unikernel space itself is relatively immature.
You don't need to emphasize the "vibe coded every time you need them" thing. That's not what anybody was being talked about in the article. The "vibe coding" piece is pointing out that the missing pieces in the ecosystem can be more rapidly filled in now because of agentic tooling.
Over time, what prevents the reviewed-and-maintained-library-code from developing creeping featuritis and consequently evolving the additional attack surface that unikernels currently lack?
> running on hypervisor direct against the virtualized hardware.
Well, here is your actual OS then. You named it "hypervisor", and changed the system interface, but it's still there, revirtualizing the access to hardware and ensuring separation of different users/applications/unikernels.
This isn't too dissimilar to DOS programs. DOS also gave you a filesystem, memory management, a shell a process loder, driver interface, but it was all in real mode, and you were free to replace these components with your own as you pleased.
Or if you're more familiar with embedded, like a BSP or RTOS
Arbitrating access to the hardware between multiple tenants still gonna be a PITA (as it was during the DOS days), especially if you want to expose actual hardware, not some generic VirtIO devices. Even with the latter, the hypervisor would have to do quite a bit of the resource management and interface translation.
Unless you're literally running a single application on a dedicated piece of hardware in which case... yeah, sure, you can do the OS-as-a-library schtick. But you could do it 10 years ago, too.
I mean, sure we can put labels wherever we want. I don't really care. MirageOS even has "OS" in its name.
The point is all the other things: total number of lines of code, permissions and security, memory management, drivers, process mgmt, it all changes.
Does it though? And I'd really like to see how you'll revirtualize e.g. an NVIDIA GPU (notoriously context-full piece of hardware), while allowing transparent shared access to it from different applications. Heck, you'll run into trouble with most of PCI-connected devices except for the most primitive once.
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