1NOTE: we have stopped maintaining the x86 version of xv6, and switched 2our efforts to the RISC-V version 3(https://github.com/mit-pdos/xv6-riscv.git) 4 5xv6 is a re-implementation of Dennis Ritchie's and Ken Thompson's Unix 6Version 6 (v6). xv6 loosely follows the structure and style of v6, 7but is implemented for a modern x86-based multiprocessor using ANSI C. 8 9ACKNOWLEDGMENTS 10 11xv6 is inspired by John Lions's Commentary on UNIX 6th Edition (Peer 12to Peer Communications; ISBN: 1-57398-013-7; 1st edition (June 14, 132000)). See also https://pdos.csail.mit.edu/6.828/, which 14provides pointers to on-line resources for v6. 15 16xv6 borrows code from the following sources: 17 JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, console.c, and others) 18 Plan 9 (entryother.S, mp.h, mp.c, lapic.c) 19 FreeBSD (ioapic.c) 20 NetBSD (console.c) 21 22The following people have made contributions: Russ Cox (context switching, 23locking), Cliff Frey (MP), Xiao Yu (MP), Nickolai Zeldovich, and Austin 24Clements. 25 26We are also grateful for the bug reports and patches contributed by Silas 27Boyd-Wickizer, Anton Burtsev, Cody Cutler, Mike CAT, Tej Chajed, eyalz800, 28Nelson Elhage, Saar Ettinger, Alice Ferrazzi, Nathaniel Filardo, Peter 29Froehlich, Yakir Goaron,Shivam Handa, Bryan Henry, Jim Huang, Alexander 30Kapshuk, Anders Kaseorg, kehao95, Wolfgang Keller, Eddie Kohler, Austin 31Liew, Imbar Marinescu, Yandong Mao, Matan Shabtay, Hitoshi Mitake, Carmi 32Merimovich, Mark Morrissey, mtasm, Joel Nider, Greg Price, Ayan Shafqat, 33Eldar Sehayek, Yongming Shen, Cam Tenny, tyfkda, Rafael Ubal, Warren 34Toomey, Stephen Tu, Pablo Ventura, Xi Wang, Keiichi Watanabe, Nicolas 35Wolovick, wxdao, Grant Wu, Jindong Zhang, Icenowy Zheng, and Zou Chang Wei. 36 37The code in the files that constitute xv6 is 38Copyright 2006-2018 Frans Kaashoek, Robert Morris, and Russ Cox. 39 40ERROR REPORTS 41 42We don't process error reports (see note on top of this file). 43 44BUILDING AND RUNNING XV6 45 46To build xv6 on an x86 ELF machine (like Linux or FreeBSD), run 47"make". On non-x86 or non-ELF machines (like OS X, even on x86), you 48will need to install a cross-compiler gcc suite capable of producing 49x86 ELF binaries (see https://pdos.csail.mit.edu/6.828/). 50Then run "make TOOLPREFIX=i386-jos-elf-". Now install the QEMU PC 51simulator and run "make qemu".