commit: f0e4591e87bac9f85246b11347f7ae5474d3713a
parent 7b5ea495c3f71e7dd61a6961a07fcd1dbc1002e1
Author: Drew DeVault <sir@cmpwn.com>
Date: Wed, 9 Aug 2023 17:39:37 +0200
Hello from Ares
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diff --git a/content/blog/2023-08-09-Hello-from-Ares.md b/content/blog/2023-08-09-Hello-from-Ares.md
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+---
+title: Hello from Ares!
+date: 2023-08-09
+---
+
+I am pleased to be writing today's blog post from a laptop running [Ares OS]. I
+am writing into an ed(1) session, on a file on an ext4 filesystem on its hard
+drive. That's pretty cool! It seems that a lot of interesting stuff has happened
+since I gave that talk on Helios at [FOSDEM] in February.
+
+[Ares OS]: https://ares-os.org
+[FOSDEM]: https://spacepub.space/w/wpKXfhqqr7FajEAf4B2Vc2
+
+
+
+The talk I gave at FOSDEM was no doubt impressive, but it was a bit of a party
+trick. The system was running on a Raspberry Pi with one process which included
+both the slide deck as a series of raster images baked into the ELF file, as
+well as the GPU driver and drawing code necessary to display them, all in one
+package. This was quite necessary, as it turns out, given that the very idea of
+"processes" was absent from the system at this stage.
+
+Much has changed since that talk. The system I am writing to you from has
+support for processes indeed, complete with fork and exec and auxiliary vectors
+and threads and so on. If I run "ps" I get the following output:
+
+```
+mercury % ps
+1 /sbin/usrinit dexec /sbin/drv/ext4 block0 childfs 0 fs 0
+2 /etc/driver.d/00-pcibus
+3 /etc/pci.d/class/01/06/ahci
+4 /etc/driver.d/00-ps2kb
+5 /etc/driver.d/99-serial
+6 /etc/driver.d/99-vgacons
+7 /sbin/drv/ext4 block0
+15 ed blog.md
+16 ps
+```
+
+Each of these processes is running in userspace, and some of them are drivers. A
+number of drivers now exist for the system, including among the ones you see
+here a general-purpose PCI driver, AHCI (SATA), PS/2 keyboard, PC serial, and a
+VGA console, not to mention the ext4 driver, based on lwext4 (the first driver
+not written in Hare, actually). Not shown here are additional drivers for the
+CMOS real-time clock (so Ares knows what time it is, thanks to Stacy Harper), a
+virtio9pfs driver (thanks also to Tom Leb for the initial work here), and a few
+more besides.
+
+As of this week, a small number of software ports exist. The ext4 driver is
+based on lwext4, as I said earlier, which might be considered a port, though it
+is designed to be portable. The [rc] shell I have been working on lately has
+also been ported, albeit with many features disabled, to Mercury. And, of
+course, I did say I was writing this blog post with ed(1) -- I have ported
+Michael Forney's [ed implementation] from sbase, with [relatively few] features
+disabled as a matter of fact (the "!" command and signals were removed).
+
+[rc]: https://git.sr.ht/~sircmpwn/rc
+[ed implementation]: http://git.suckless.org/sbase/file/ed.c.html
+[relatively few]: https://git.sr.ht/~sircmpwn/sbase/commit/ee0336bc3b6f55839785427d6184e6f897055e31
+
+This ed port, and lwext4, are based on our C library, designed with drivers and
+normal userspace programs in mind, and derived largely from musl libc. This is
+coming along rather well -- a few features (signals again come to mind) are not
+going to be implemented, but it's been relatively straightforward to get a large
+amount of the POSIX/C11 API surface area covered on Ares, and I was pleasantly
+surprised at how easy it was to port ed(1).
+
+There's still quite a lot to be done. In the near term, I expect to see the
+following:
+
+* A virtual filesystem
+* Pipes and more shell features enabled, such as redirects
+* More filesystem support (mkdir et al)
+* A framebuffer console
+* EFI support on x86\_64
+* MBR and GPT partitions
+
+This is more of the basics. As these basics unblock other tasks, a few of the
+more ambitious projects we might look forward to include:
+
+* Networking support (at least ICMP)
+* Audio support
+* ACPI support
+* Basic USB support
+* A service manager (*not* systemd...)
+* An installer, perhaps a package manager
+* Self-hosting builds
+* Dare I say Wayland?
+
+I should also probably do something about that whining fan I'm hearing in the
+background right now. Of course, I will also have to do a fresh DOOM port once
+the framebuffer situation is improved. There's also still plenty of kernel work
+to be done and odds and ends all over the project, but it's in pretty good shape
+and I'm having a blast working on it. I think that by now I have answered the
+original question, "can an operating system be written in Hare", with a
+resounding "yes". Now I'm just having fun with it. Stay tuned!
+
+Now I just have to shut this laptop off. There's no poweroff command yet, so I
+suppose I'll just hold down the power button until it stops making noise.
