
Old-School Disk Partitions - zdw
https://bsdimp.blogspot.com/2020/07/old-school-disk-partitioning.html
======
h2odragon
> Swap was put in between the used parts of other of the disk. This was tricky
> to get right, since you had to map out the system.

... one of the classic mistakes, well after the era the author refers to here,
was to overlap a swap and filesystem partition. Worked just fine until that
last block of swap got used; then suddenly the filesystem's hosed... but it
repaired ok and then was good for sometime, until the same would happen again.

gaps in between partitions could provide useful hidden space for all manner of
things too.

Someone recently posted an overlapped filesystem stunt that was at the same
time a valid FAT and ext2? volume; i think. Can't recall enough of it to find
a link now.

~~~
merlinscholz
You're probably referring to this:
[https://news.ycombinator.com/item?id=22055145](https://news.ycombinator.com/item?id=22055145)

~~~
h2odragon
that's the bunny, thanks very much

------
tyingq
_" The 3rd edition has the enigmatic /crp filesystem documented for one of the
drives (I wonder what it's an abbreviation for):"_

"Crap" is what first comes to mind, but Rob Pike seems to confirm /crp was
short for "creep":
[https://inbox.vuxu.org/tuhs/CAKzdPgzPtnPQoUwGpTeaQjhfW8zUHsO...](https://inbox.vuxu.org/tuhs/CAKzdPgzPtnPQoUwGpTeaQjhfW8zUHsOnAbtw=eOB0454TyUUjg@mail.gmail.com/)

Side note: I can only find this single reference to that backstory. Seems we
are pretty close to losing a lot of history.

------
jake_morrison
I have worked on embedded Linux systems recently enough where I had to change
the driver and recompile the kernel to repartition the disk. It was just a
chunk of Flash memory, and it was up to the driver to tell it what to be.

~~~
jschwartzi
I’ve done this and created overlapping regions to repartition the NAND. Mtd
devices are frustrating because their partition layout is set at compile-time
so if you want to change layouts you have to recompile the kernel. And if you
need to migrate from one partition scheme to another you have to have
partitions defined for both schemes in the same kernel.

