A journey to io_uring, AIO and modern storage devices While main memory is considered to be rather cheap by some systems designers it is not always possible to store everything in the main memory. When data is stored in external memory one has to think carefully how to access the data. There are several kind of storage devices and more than one system call to read from them. We performed experiments to find out how different Linux system calls perform for available devices. In total HDD, SATA SSD, NVMe SSD, and Intel Optane were accessed via single-threaded and multi-threaded pread, Linux aio, and new io_uring interfaces. Full report is available in PDF format:link.