- Author
- Rachel Gordon, MIT CSAIL
- Published
- 10 June 2026
- Kind
- University news article about a research paper
- Original
- news.mit.edu/2026/to-study-how-chips-really-work-mit-researchers-built-their-own-operating-system-0610
- Subject
- Systems and hardware
What it is
Rachel Gordon of MIT CSAIL wrote the article. It covers Fractal, built by a team led by PhD student Joseph Ravichandran. The article explains the problem, the design and the findings on branch predictors.
What it says
- The article says Fractal is a kernel written from scratch, which boots on bare metal.
- It says the technique lets one experiment switch privilege levels while running the same instructions.
- It says Fractal confirmed the M1 blocks user code steering kernel execution via indirect branches.
- It says the M1 still fetches the target into cache, visible to a side channel.
- It says the team found the first evidence of Phantom speculation on Apple Silicon.
- It says the conditional branch predictor has no privilege isolation on either core type.
- It says Fractal has over 31,000 lines of code and supports x86_64, ARM64 and RISC-V.
What evidence it gives
The article reports findings from the paper in plain terms. It quotes the lead author and one outside professor. It gives no data tables or measurements.
Interests and limits
MIT published this about its own researchers' work. The linked paper was not read, so no claim was checked against it. The only outside voice is one professor, who praised the work. The article says Apple's engineers examined Fractal but gives no response.