- Messier 109 (also known as NGC 3992 or the Vacuum Cleaner Galaxy) is a barred spiral galaxy exhibiting a weak inner ring structure around the central bar approximately 67.2 ± 23 million light-years away in the northern constellation Ursa Major. M109 can be seen south-east of the star Phecda (γ UMa, Gamma Ursa Majoris).
- Why did x86 support self-modifying code in the 80s and 90s? (stackexchange.com)
On the simplest microprocessors, self-modifying code is not a special problem. On an 8080, you can write just ahead of the instruction pointer, and a few clock cycles later, the instruction you just wrote, will be fetched and executed as though it had been there all along. But as pipelines and instruction cache are introduced, this becomes more problematic.