Re: [ANN] Squashfs 3.0 released

From: Jeff Garzik
Date: Fri Mar 17 2006 - 12:23:09 EST


Phillip Lougher wrote:
On 17 Mar 2006, at 16:00, Jeff Garzik wrote:
Jörn Engel wrote:
The one still painfully missing is a
fixed-endianness disk format.

Fixed endian isn't necessarily a requirement. Detectable endian is. As long as (a) the filesystem mkfs notes the endian-ness and (b) the kernel filesystem code properly handles both types of endian, life is fine.

That's what is currently done. There are two filesystem formats, big endian (donated by Squashfs magic of 'sqsh') and little endian (denoted by Squashfs magic of 'hsqs'). The kernel code detects the filesystem endianness and swaps if necessary.

Well, then, I don't see a need to change anything. As I said, [consistent and] detectable endian is the real requirement. For SquashFS's users, I would think they would prefer the current situation (selectable endian) to fixed endian, because many SquashFS users need to squeeze every ounce of performance out of severely resource-constrained devices.

I have two routers, ADM5120-based Edimax and LinkSys WRT54G v5, both of which have a mere 2MB of flash, and both use SquashFS to maximize that space. And both are el cheapo, slow embedded processors that run far slower than 300Mhz. I look askance at anyone who wants to make an arbitrary filesystem design decision imposing tons of bytesex upon these lowly devices.

Jeff


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