The road to Zettalinux

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2022-09-23 13:00:33

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By Jonathan Corbet September 16, 2022 LPC Nobody should need more memory than a 64-bit pointer can address — or so developers tend to think. The range covered by a pointer of that size seems to be nearly infinite. During the Kernel Summit track at the 2022 Linux Plumbers Conference, Matthew Wilcox took the stage to make the point that 64 bits may turn out to be too few — and sooner than we think. It is not too early to start planning for 128-bit Linux systems, which he termed "ZettaLinux", and we don't want to find ourselves wishing we'd started sooner.

The old-timers in the audience, he said, are likely to have painful memories of the 32-bit to 64-bit transition, which happened in the mid-1990s. The driving factor at the time was file sizes, which were growing beyond the 2GB that could be represented with signed, 32-bit numbers. The Large File Summit in 1995 worked out the mechanisms ("lots of dreadful things") for handling larger files. Developers had to add the new lloff_t size for 64-bit file sizes and the llseek() system call to move around in large files. Wilcox said that he would really prefer not to see an lllseek() for 128-bit offsets.