[Cerowrt-devel] Is there a particular reason cerowrt isn't using UBIFS?

David Lang david at lang.hm
Sun Aug 31 15:37:07 EDT 2014

On Sun, 31 Aug 2014, Theodore Ts'o wrote:

> On Sun, Aug 31, 2014 at 12:05:52AM -0700, David Lang wrote:
>> One other place this sort of thing is likely to be useful is for Raspberry
>> Pi and other small (embedded by some defintions) systems that use SD cards
>> for their OS system. The I/O to the storage is so slow that the saved I/O
>> time is likely to more than cover the cost of the decompression.
> Yeah, that's the main argument I've heard for wanting to do
> decompression; it's to speed up I/O when using HDD's and cheap flash
> that has a minimal number of flash channels.

As a datapoint in this discussin, take a look at the openwrt thread
[OpenWrt-Devel] Toolchain issue: Significant decrease in performance of binaries 
produced by Barrier Breaker relative to Attitude Adjustment

Apparently with BB they changed the gcc options on mips to produce 16 bit code 
because it results in smaller binaries, but this cripples performance in some 

It doesn't answer your funding issue, but it shows another case of people being 
very sensitive to storage size.

David Lang

>> Raspberry Pi systems have had to move to 4G cards as their base because it's
>> just not possible to have the standard install do more than boot on a 2G
>> card.
> 2G SD cards --  $42.95 for a 10-pack
> 4G SD cards --  $53.95 for a 10-pack
> I have a design for adding compression, but except as a hobby effort,
> I've had a lot of trouble finding a company who would be willing to
> support an engineer to actually do the effort.  :-(
> Unless the company is making a truly vast number of devices, and are
> very sensitive to the BOM cost, it might not make sense from an
> engineering / business plan point of view.
> So it will probably be something I do "for fun", when I can find the
> time.... and there are a lot of other projects where companies are
> willing to sponsor engineers to add new features, such as encryption,
> reflink support, data checksums, etc., where if I can help them land
> those features, it's unfortunately going to be higher priority than my
> personally working on compression support for ext4.
> But if someone is interested in working on it, they should talk to me;
> I'd be happy to work with someone interested in working on the
> project.
> 							- Ted

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