21.1.1 The Linux Kernel
The first Linux kernel released to the public was Version 0.01, dated May
14, 1991. It had no networking, ran only on 80386-compatible Intel processors
and PC hardware, and had extremely limited device-driver support. The virtual
memory subsystem was also fairly basic and included no support for memory mapped
files; however, even this early incarnation supported shared pages
with copy-on-write. The only file system supported was the Minix file system
-the first Linux kernels were cross-developed on a Minix platform. However,
the kernel did implement proper UNIX processes with protected address spaces.