FreeBSD Device Drivers Book
github.com
github.com
Every update I clone the current boot environment, execute it as a jail, run upgrades in there, and then once upgrades finish I set it to "boot just once", all using the built in bectl. At no point during an upgrade is the running OS in an inconsistent state. Powerloss during upgrade? no problem, since it wasn't activated yet your server comes up with the previous version. And you can either junk the partial upgraded env and start over, or jail it again and continue.
I only wish laptop support was a bit better. But since my laptop is more of a pet, at least it can have Void.
I think (Open)SUSE does something similar using BTRFS snapshots. But yes, ZFS-backed BEs are the best IMHO:) OpenIndiana still does them, of course, but yeah that's sadly niche.
I have run the Kalpa Desktop, which is basically MicroOS + KDE, and yes that's almost exactly the same setup; updates/changes are done using transactional-update, which AIUI performs the change in a new root snapshot/filesystem and then you reboot to make it take effect. Honestly a very nice system, although I eventually abandoned it because I was ultimately unwilling to run on BTRFS (which I absolutely do not trust).
If something in a translated edition seems unclear, inconsistent, or technically questionable, please refer to the English version as the source of truth. Help with reviewing and improving the translations is very welcome (see Contributing below)."
---
This doesn't directly answer your question though.
So I would expect that they would thoroughly check the book for inaccuracies, errors and issues before releasing it after proof-reading, otherwise it would say a lot about how they use LLMs and not checking over it would hurt their own reputation.
a) it's a good introduction to C
b) a human read any of it
https://github.com/ebrandi/FDD-book/blob/main/content/chapte...
This book is a dishonest AI scam.
The scam is not stating up front "this was written by an LLM and I haven't read it." The dishonesty is claiming this book will teach you such-and-such when the author actually has no idea. It really is a scam. Even if he's not making anything directly, he's already earned 150 stars in the GitHub pseudoeconomy, plus good word-of-mouth from people who are lazy and thoughtless like he is, people who assumed that 4,500 pages about FreeBSD from a lead FreeBSD maintainer must be worth something and didn't bother to check if it was written by an LLM... even though it's 2026.
This book has negative value. It is actively destructive to FreeBSD, even if in the short term it boosts the author's public profile.
I won't be that radical, the book still has value. There are many useful code samples with descriptions and explanations of concepts I did not know before. But to get to them one has to dig through a forrest of useless tokens. Someone has to pass it through an LLM and publish distilled edition. :-)
Indeed! I read through a couple of paragraphs. Each begins with a bloated introduction where each sentence repeats same idea many times in different words. Lot's of bullets repeating same statement. That's exactly how LLM scam looks like. The whole book is full of water. It can be reduced in size by a factor of 5.
I would rather the author automate the mundane and focus on conveying their ideas clearly.
As an aside, is there a Linux version for this ?
Look at this totally useless """introduction""" to C: https://github.com/ebrandi/FDD-book/blob/main/content/chapte...
First of all this is an entire book, it's 76,000 words. But look at the first nontrivial example of C after "hello world," under "Bonus learning point about C return values"
exec_map_first_page(struct image_params *imgp)
{
vm_object_t object;
vm_page_t m;
int error;
if (imgp->firstpage != NULL)
exec_unmap_first_page(imgp);
object = imgp->vp->v_object;
if (object == NULL)
return (EACCES);
#if VM_NRESERVLEVEL > 0
if ((object->flags & OBJ_COLORED) == 0) {
VM_OBJECT_WLOCK(object);
vm_object_color(object, 0);
VM_OBJECT_WUNLOCK(object);
}
#endif
error = vm_page_grab_valid_unlocked(&m, object, 0,
VM_ALLOC_COUNT(VM_INITIAL_PAGEIN) |
VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
if (error != VM_PAGER_OK)
return (EIO);
imgp->firstpage = sf_buf_alloc(m, 0);
imgp->image_header = (char *)sf_buf_kva(imgp->firstpage);
return (0);
}
Edit: I mean look at the intro to for loops. This is supposed to be for total beginners. Example 1:
for (int i = 0; i < 10; i++) {
printf("%d\n", i);
}
>> Repeat while i < 10
>> Increment i each time by 1 (i++)
Example 2:
for (i = 0; n > 0 && i < IFLIB_MAX_RX_REFRESH; n--, i++) {
struct netmap_slot *slot = &ring->slot[nm_i];
uint64_t paddr;
void *addr = PNMB(na, slot, &paddr);
/\* ... work per buffer ... \*/
nm_i = nm_next(nm_i, lim);
nic_i = nm_next(nic_i, lim);
}
>> * The driver is refilling receive buffers so the NIC can keep receiving packets.
>> * It processes buffers in batches: up to IFLIB_MAX_RX_REFRESH each time.
>> * i counts how many buffers we've handled in this batch. n is the total remaining buffers to refill; it decrements every iteration.
>> * For each buffer, the code grabs its slot, figures out the physical address, readies it for DMA, then advances the ring indices (nm_i, nic_i).
>> * The loop stops when either the batch is full (i hits the max) or there's nothing left to do (n == 0). The batch is then "published" to the NIC by the code right after the loop.
>> In essence, a for loop is the go-to choice when you have a clear limit on how many times something should run. It packages initialisation, condition checking, and iteration updates into a single, compact header, making the flow easy to follow.
Total garbage. This has literally zero educational value. I assume Brandi is just trying to make a quick buck, he truly has not even glanced at the output. He should be ashamed of himself.
you yourself chose to spend time on something to your own frustration even though at that point you already knew it wasnt for you. frustrating yourself further trying to find examples to help frustrate others too.
look at how you are behaving and then realise you are saying someone else should be ashamed of themselves.
If you disagree with the book a simple excerpt and note would suffice. if it's 'super clearly bad' it does not need to contain a load of emotions to transmit that message.
By publishing a free book without even a way to donate?
if people dont get too 'anti' about it, it might grown into a good book at some point over editions.
It would certainly be useful to have such a book be complete and maintained (tons of work ofc).
personally id prefer a book that requires abit more prework, like learning C etc. and Unix, so it can be more compact specific to device drivers. 4k+ pages is a lot to chew through and more a thing for reference manuals like intel/amd/acpi manuals etc. (lot of tables and diagrams etc.)
I used to point at LFS/BLFS in the past (Linux from scratch), since the idea is great. Unfortunately they are now systemd-only, which kind of defeats some of the points, IMO. But documentation is useful, so FreeBSD improving here is good. Perhaps one day it can compete against Linux again. :D
Could you be more specific? Maybe open an issue listing points for possible improvement?
Awesome work!
I await the Linux version :)
> Do I need to know C before starting?
> No. Chapters 4 and 5 teach C from the ground up, focusing on the parts of the language that matter for kernel work (pointers, structures, memory layout, the preprocessor, and calling conventions). If you already know C well, sidebars in those chapters tell you what to skim and what to read carefully.
> Do I need to know UNIX or FreeBSD?
> No. Chapter 2 walks you through installing FreeBSD in a VM or on bare metal, and Chapter 3 introduces the UNIX command line, filesystem, processes, permissions, and editors. By the end of Part 1 you will have a working lab and the vocabulary to use it.
If you're trying to get more contributors to your project, that seems like an excellent way to do it:) You have any interest in working on the project? Great, here's everything to get you there!