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mit-pdos
xv6-riscv
C2019–2025
mit-pdos / xv6-riscv

xv6-riscv

Xv6 for RISC-V

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13Distinct people
15Mentions
0Explicit recommenders
10.8KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Xv6 for RISC-V

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

No recommendation phrase was found in the indexed comments.

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Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 5:04:57 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year15 dated mentions

Observed mentions: 2019-09-22 07:02:53 UTC to 2025-09-10 01:10:19 UTC.

0123452019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments20192020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 2 mentions; 2 submissions, 0 comments20222023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 5 mentions; 0 submissions, 5 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC211
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC202
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC000
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC220
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC303
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC101
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC505

What Hacker News says

15 sources
johndoe0815·Jul 28, 2024
It depends a bit on your objectives - do you want to build your own OS, learn more about the theory and algorithms used in operating systems, or do you want to know details about commercial OSes? For a hands-on view on building operating systems, I can recommend taking a look at xv6 [1] as the next step. This is a modern reimplementation of a subset of the 6th edition Unix, running on RISC-V in its current version (an older version targeted x86) [2]. The classical textbooks used in OS courses (Tanenbaum's "Modern Operating Systems", Silberschatz' "Operating System Concepts" and Stallings' "Operating Systems") are more on the theoretical side, whereas Tanenbaum's Minix books are more hands-on. A current, somewhat more hands-on, textbook is "Operating Systems: Three Easy Pieces" by Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau. Addit
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ional bonus - it's free [3]. For more hands-on resources, there's a lot of material available. osdev.org [4] provides lots of OS development knowledge in wiki form, Stephen Marz' "The Adventures of OS: Making a RISC-V Operating System using Rust" [5] is a hands-on course written as a series of blog posts to build your own OS for RISC-V (but it needs to be updated since RISC-V has changed in some details since the articles were published). I learned about OS theory and practice using Doug Comer's Xinu books [17] and I still think these are very useful. You can then dig into older Unix(-like) systems, e.g. BSD [6,7] and/or check out more modern approaches such as Microkernels (I can especially recommend L4, starting from Jochen Liedtke's papers [8] and checking out work on seL4 [9]), capability-based systems (CHERI [10] and an old, but good overview book on capability architectures [11]), or - for something a bit more exotic - Plan 9 [12]. If you want to gain an insight into commercial operating systems, there are a number of interesting books on Apple's OS X and iOS [13,14], Windows [15] and even VMS [16]. [1] https://github.com/mit-pdos/xv6-riscv/ [2] Russ Cox, Frans Kaashoek, Robert Morris xv6: a simple, Unix-like teaching operating system https://pdos.csail.mit.edu/6.S081/2020/xv6/book-riscv-rev1.pdf [3] https://pages.cs.wisc.edu/~remzi/OSTEP/ [4] https://wiki.osdev.org/Main_Page [5] https://osblog.stephenmarz.com [6] Marshall Kirk McKusick , Keith Bostic, Michael J. Karels The Design and Implementation of the 4.4BSD Operating System Addison Wesley, ISBN-13: ‎ 978-0201549799 [7] Marshall Kirk McKusick, George V. Neville-Neil, Robert N.M. Watson The Design and Implementation of the FreeBSD Operating System Addison Wesley, ISBN-13: 978-0321968975 [8] https://en.wikipedia.org/wiki/L4_microkernel_family [9] https://sel4.systems [10] https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ [11] Henry M. Levy Capability-Based Computer Systems https://homes.cs.washington.edu/~levy/capabook/ [12] Francisco J Ballesteros Notes on the Plan 9 3rd edition Kernel Source http://www.r-5.org/files/books/computers/internals/unix/Francisco_Ballesteros-Note… [13] Amit Singh Mac OS X Internals: A Systems Approach Pearson 2006, ISBN-13: 978-0-321-46795-9 [14] Jonathan Levin *OS Internals (Volume I: User Mode, Volume II:Kernel Mode, Volume III: Security & Insecurity) https://newosxbook.com/home.html [15] https://learn.microsoft.com/en-us/sysinternals/resources/windows-internals [16] VAX/VMS Internals and Data Structures http://www.bitsavers.org/pdf/dec/vax/vms/training/EY-00014-DP_VMS_Internals_and_Da… [17] https://xinu.cs.purdue.edu
In Ask HN: What Comes After John Lions' Unix Commentary?
kelas·Sep 9, 2023
> True, but when making an OS, assembly code is an incredibly small part of it. A few comments up this thread i briefly mentioned r/xv6 entry.S, so here’s what i meant: rv64: https://github.com/mit-pdos/xv6-riscv/blob/riscv/kernel/entr... amd64: https://github.com/dancrossnyc/rxv64/blob/main/kernel/src/en... > You basically need to run a few instructions to put the processor in the right mode, and you need ONE line of assembly code (often inline C) to allow usermode to call supervisor mode. Right… Please see above. Also, in riscv land we have machine, supervisor and user modes, with hypervisor mode being in the works. > When choosing an architecture for a learning OS, I think other factors would dominate, like availability of hardware (many people have a PC already, saving them $100-$200 on RISC-V hardware). yet, MIT PDOS thinks Fabrice B
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ellard’s ubiquitous qemu is a better, cheaper and more forgiving starting point, although i personally prefer to spend a few bucks on something as absurdly cheap and cool as kendryte k210/k510 SoC and enjoy the real deal. > Intel hate keeping tech is irrelevant [I don’t care] Yes, it’s just you. Also, it runs Minix.
In The rxv64 Operating System: MIT's xv6, in Rust, for SMP x86_64 machines
kelas·Sep 9, 2023
okay, fair. i only got misled by the title of the post, which claims all-rust xv6 port. now that we cleared the userland part, here’s what I’m contemplating on the kernel side. i can’t think of anything simpler and more staple than this, so: https://github.com/dancrossnyc/rxv64/blob/main/kernel/src/ua... https://github.com/mit-pdos/xv6-riscv/blob/riscv/kernel/uart... honestly - i don’t feel at ease to tell which driver code is more instructional, which is easier to read, which is better documented, which is better covered with tests, which has more unsafety built into it (explicit or otherwise), what size are the object files, and what is easier to cross-compile and run on the designated target from, say, one of now-ubiquitous apple silicon devices. lest we forget that the whole point of it is “pedagogical”, i.e. to learn something about
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how a modern OS can be organized, and how computer generally works. and i’m just not sure.
In The rxv64 Operating System: MIT's xv6, in Rust, for SMP x86_64 machines
johndoe0815·Aug 4, 2023
The x86 version of xv6 is no longer updated, the last updates took place about 7 years ago. Current xv6 supports RISC V in qemu, there are also ports to real RISC V devices (Kendryte/Canaan K210 by Huazhong University of Science and Technology, Allwinner D1 and StarFive JH7110 by me) and FPGA implementations (by Michael Schröder). https://github.com/mit-pdos/xv6-riscv/ (qemu) https://github.com/HUST-OS/xv6-k210 (K210) https://github.com/michaelengel/xv6-d1 (Allwinner D1) https://github.com/michaelengel/xv6-vf2 (JH7110) https://gitlab.com/x653/xv6-riscv-fpga (RV32 FPGA)
In Xv6: A modern, x86 reimplementation of 6th Edition Unix
agomez314·Oct 4, 2022Submission

Ask HN: Examples of Microkernels?

I'm reading through the MIT xv6 OS handbook and code (here: https://github.com/mit-pdos/xv6-riscv/) and they mention the fact that they created it as a monolithic kernel since most unix systems are monolithic. They then introduce the microkernel concept. Are there microkernel concepts out there (especially code) I can check out? I'm curious to see how userspace processes communicate to kernel processes to execute privileged actions.
80 points · Open discussion
kick·Mar 8, 2020
* tweetnacl.cr.yp.to Crypto library in the size of a hundred tweets [ https://twitter.com/tweetnacl ] by the only person with a genuine claim to being able to write safe C & company. * https://github.com/mit-pdos/xv6-public & * https://github.com/mit-pdos/xv6-riscv UNIX v6 clone in ANSI C by influential Plan 9-era Bell Laboratories employee and now influential Google employee Russ Cox, along with influential computer virus author and son of one of the original UNIX authors Robert T. Morrison; entire source code fits in under a hundred pages of well-typeset documents [ warning, old copy, you should generate a modern one: https://pdos.csail.mit.edu/6.828/2011/xv6/xv6-rev6.pdf ].
In Ask HN: How do I learn C properly?

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