Origin of "partition" in storage devices

Warner Losh imp at bsdimp.com
Tue Feb 1 17:00:06 CST 2022


On Tue, Feb 1, 2022 at 12:42 PM Grant Taylor via cctalk <
cctalk at classiccmp.org> wrote:

> On 2/1/22 2:14 AM, Joshua Rice via cctalk wrote:
> > There's several advantages to doing it that way, including balancing
> > wear on a disk (especially today, with SSDs), as a dedicated swap
> > partition could put undue wear on certain areas of disk.
>
> I thought avoiding this very problem was the purpose of the wear
> leveling functions in SSD controllers.
>

All modern SSD's firmware that I'm aware of decouple the physical location
from the LBA. They implement some variation of 'append store log' that
abstracts out the LBAs from the chips the data is stored in. One big reason
for this is so that one worn out 'erase block' doesn't cause a hole in the
LBA
range the drive can store data on. You expect to retire hundreds or
thousands of erase blocks in today's NAND over the life of the drive, and
coupling LBAs to a physical location makes that impossible.

Warner


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