Hi, I've tried to copy some different files to an USB flash disk and an USB HDD and tried different USB hubs. After a while the system gets very slow, switching between windows can take quite a while. The copying speed is slow, too(only several MB/s to an empty USB HDD). The machine is not old, just bought it this year. And on the same machine the same problem is not seen on Ubuntu 10.04 and Windows 7. Any ideas?
On Tue, 2011-07-05 at 17:01 +0800, 某因幡 wrote:
Hi, I've tried to copy some different files to an USB flash disk and an USB HDD and tried different USB hubs. After a while the system gets very slow, switching between windows can take quite a while. The copying speed is slow, too(only several MB/s to an empty USB HDD). The machine is not old, just bought it this year. And on the same machine the same problem is not seen on Ubuntu 10.04 and Windows 7. Any ideas?
Flash and HDD are two different cases. Flash drives can become slow because of their internal architecture, fragmentation, wear leveling etc. (lots of info on this via Google). I use an 8GB pen drive a lot and every so often find it useful to reformat it completely, which seems to help. This is a VFAT drive since it has to be compatible with another (non-Linux) system.
In the HDD case, you may just have a slow USB port. Check if it's USB-1, USB-2 or USB-3 (unlikely at the moment). And remember that USB doesn't do DMA, so writing large amounts of data means soaking up CPU time.
poc
On Tue, 2011-07-05 at 22:09 +0200, Reindl Harald wrote:
Am 05.07.2011 18:14, schrieb Patrick O'Callaghan:
Flash drives can become slow because of their internal architecture, fragmentation, wear leveling etc.
flash drive and fragmentation? jokingly?
No, not joking, though fragmentation is probably the wrong term. What I meant was that flash drives work in fixed-size units which a) are usually not the same as the filesystem allocation size, and b) must be erased before being written on, i.e. writing one byte costs almost the same as writing a full unit (in fact it could conceivably cost more because in the one-byte case the rest of the unit has to be read first). If a file is not aligned with these units then more of them than necessary will need to be read, erased and rewritten, slowing the process down. One could probably design a pathological worst case that takes twice as long as the best case.
poc
06.07.2011, 01:14, "Patrick O'Callaghan" pocallaghan@gmail.com:
On Tue, 2011-07-05 at 17:01 +0800, 某因幡 wrote:
Hi, I've tried to copy some different files to an USB flash disk and an USB HDD and tried different USB hubs. After a while the system gets very slow, switching between windows can take quite a while. The copying speed is slow, too(only several MB/s to an empty USB HDD). The machine is not old, just bought it this year. And on the same machine the same problem is not seen on Ubuntu 10.04 and Windows 7. Any ideas?
Flash and HDD are two different cases. Flash drives can become slow because of their internal architecture, fragmentation, wear leveling etc. (lots of info on this via Google). I use an 8GB pen drive a lot and every so often find it useful to reformat it completely, which seems to help. This is a VFAT drive since it has to be compatible with another (non-Linux) system.
In the HDD case, you may just have a slow USB port. Check if it's USB-1, USB-2 or USB-3 (unlikely at the moment). And remember that USB doesn't do DMA, so writing large amounts of data means soaking up CPU time.
I think it only must be slow, the copying process. But, I have an 8GB SD HC card in my phone which connects via a miniUSB cable, and when I copy mp3 files it hangs the whole system. The mouse cursor stops responding.
I think a bug report should be created. Not sure about the component, though.
-
Misha Shnurapet -
Patrick O'Callaghan -
Reindl Harald -
某因幡