I am currently at the hypothesis stage. My hypothesis is that something is causing an excessive number of reads/writes to a small portion of a USB memory stick. My first guess is that the problem is the interaction of _cheap_ usb chips/firmware and the filesystem overlay.
The test are described at http://wiki.laptop.org/go/NAND_Testing . Each test is an instance of Sugar running off an USB stick in qemu. I am not sure how accurate these test are because of qemu and system level caching. At this point I am just running a hacked version of the above test until the SoaS instance to fails. Standard SoaS fails within a few hours. Installing the SoaS overlay as an ext2 filesystem has lasted about 10X time longer before I stopped the tests. It is going to take me a while to understand what these tests mean (if they mean anything) and if other qemu or system factors are screwing up the results.... david On Wed, Sep 9, 2009 at 3:39 PM, Martin Dengler<mar...@martindengler.com> wrote: > On Wed, Sep 09, 2009 at 03:21:50PM -0500, David Farning wrote: >> Thanks for joining us Douglas. >> >> I would like to point out that there are two separate yet interlinked >> issues at hand: >> 1. Easy and fast install. >> 2. Running OS natively on removable solid state media. > > What do you mean by "running OS natively"? > >> >> Douglas' Liveos solved the first issue. It is very fast and easy to >> install an OS to a hard drive by dd'ing the contents of the overlay to >> the hard drive. >> >> I am suggesting that ease of installation to another medium is not >> longer the primary usecase for SoaS. > > Caroline continues to ask for easy ways to duplicate a stick. > >> The primary use case is now running Sugar and the underlying OS as >> natively as possible on the removable solid state media. The primary >> goals are now reliability and speed. > > What does "as natively as possible" mean? > >> The issue is not that overlays are bad/good or real file systems. The >> issue is, can SoaS improve stick reliable and speed by eliminating >> the overlays and writing the _contents_ of the overlay directly onto >> the solid state device > > Is what you're saying that it's easier to corrupt a bit on the overlay > than it is to corrupt a bit on a non-overlay fs? > >> using a file systems which is aware of the design characteristics of >> current generations of USB keys. > > Please clarify what you mean. > >> I have been conducting some very initial tests using WAD's SD card >> test tools. > > Where can these be found? > >> #1. Standard SOAS. >> #2. Install the contents of the SoaS overlay to a usb key using >> # ext2. > > Meaning what exactly? > >> I am just running various methods of installing soas on USB sticks in >> qemu directly from usb sticks using >> >> qemu -hda /dev/sd* >> >> My initial runs using the cheapest drives I could find at best buy >> indicate that #2 has at least 10X the lifetime as #1. > > What are the units in which you're measuring "lifetime"? > >> david > > Martin > _______________________________________________ Sugar-devel mailing list Sugar-devel@lists.sugarlabs.org http://lists.sugarlabs.org/listinfo/sugar-devel