readahead is a system call of the Linux kernel that loads a file's contents into the page cache, providing that way a file prefetching technology. When a file is subsequently accessed, its contents are read from the main memory (RAM) rather than from a hard disk drive (HDD), resulting in much lower file access latencies due to much higher bandwidth of the main memory. In Linux distributions that use systemd, readahead binary (as part of the boot sequence) is replaced by systemd-readahead.. In debian-beisen plätforms laik Ubuntu, nigè softwär wa folowen jenereiçion konsisten: