I'm not an expert in this particular area, but don?t you think that FLASH memory doesn't work same as hard-drives? HDs are consisted of magnetic plates, cylinders and clusters. FLASH memory doesn't have such structure. One of results is that there is no need for de-fragmentation of FLASH SSDs.
I also suspect that problem is small size of transfer buffer, and read/write error checking per each transfer, but also wish to point that there is no need for checking weather are clusters adjacent. Just because it is FLASH memory. Weather it is attached via USB or SATA port (as with SSDs), it doesn't matter. Regards, Uros Nedic Belgrade, Serbia -----Original Message----- From: desktop-discuss-boun...@opensolaris.org [mailto:desktop-discuss-bounces at opensolaris.org] On Behalf Of J?rgen Keil Sent: June 17, 2009 7:23 PM To: desktop-discuss at opensolaris.org Subject: Re: [desktop-discuss] Slow USB speed. Why? > For some reason the [pcfs filesystem] driver on Solaris is painfully slow since I think it does a > write and verify for each block of data - this means that copying lots or large > files over to it can be VERY slow. I suspect it is slow because is reads / writes in pcfs "cluster" size units. This can be seen in "iostat -xnzc 5" output; divide the kilobyte/s value by the ops/s any you'll get the pcfs' cluster size. > The same operation on a Linux or WinXP machine can be a lot faster. I suspect both optimize the case where adjacent clusters are accessed and perform i/o in bigger chunks. > There was a bug logged against this, but I don't know > if it's going to ever be fixed. E.g. this one (but I guess there are more): http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6720764 -- This message posted from opensolaris.org _______________________________________________ desktop-discuss mailing list desktop-discuss at opensolaris.org
