Re:Unikernels were hard. key word: were
by cmrdporcupine on Tuesday October 13, 2026 @09:26AM
(#50071387)
Part of the problem with being old like I've become... and having used Linux since 1991 on a 486 is that in my mind Linux can still be thing I installed off a few 1.44MB 3.5" floppies and ran -- complete with emacs and XFree86 -- in under 8MB of RAM.
Sel4 is cool stuff.
I think it's still possible to make a Linux boot/root floppy, but it's a lot more difficult than it used to be, and it can be hard to find the 1.44MB 3.5" floppy drive in the junk closet. I don't think you were ever getting GNU Emacs on there, though — maybe JOVE.
Linux is about 40 million lines of code, and even if you disable almost everything optional, it's hard to get a usefully bootable Linux below about a megabyte.
The seL4 kernel is about 9000 lines of code, a code base that's 4000 times smaller, and I think it compiles to about 80KiB, about 12× smaller than Linux.
I elicited a small unikernel web server from Claude the week before last, and, not counting lwIP, it's 385 lines of code. The built unikernel image, which does include lwIP, is 58K, about 17× smaller than Linux.
The KokalOS kernel I've been working on over the last week, originally by refactoring the unikernel web server, is currently about 900 lines of code (65536× smaller than Linux) and compiles to just under 10KiB (128× smaller than Linux), but it's currently just running a CLI and a web server with a single Ethernet card. I anticipate that in a finished state it will probably be close to the size of seL4.