On Fri, 27 Jan 2006, Levi Bard wrote:
> On 1/27/06, Eben King <eben1@tampabay.rr.com> wrote:
>> So I copied a lot of data (around 120 GB) from /dev/hdb (IDE/ATAPI) to
>> /dev/sda (IDE/ATAPI in an external USB case). This took a while. I noticed
>> that hdb seemed to transfer data only about a third to half the time, while
>> sda worked continuously (image here: http://24.94.123.65:81/ide-usb.jpg).
>> What's the deal? Is hdb really 2-3 times faster than sda?
>
> Is it a USB2 case/port? USB1 is only like 12Mbit/s (1.5MB/s), and
> USB2 is 480Mbit/s (60MB/s)
Case, yes. http://www.newegg.com/Product/Product.asp?Item=N82E16817145656
Port, pretty sure. For some reason, it's not letting me access it now.
It's denying the existence of any SCSI drive. There's no /dev/sd? and even
mknoding ones elsewhere doesn't work. /etc/init.d/udev complains about
being launched from a terminal. When I boot, the module for eth0 (8139too)
is unloaded; when I modprobe it, stuff works (except for udev). What's up?
Some ports on that machine are USB 2 and some are USB 1.1, I think. But I
think that if it were in a USB 1.1 port, hdb would run a lot less than 1/3
the time. (~30 MB/s)/(1.5 MB/s) = about 20.
For reference,
root@pc:~# hdparm -tT /dev/hda /dev/hdb
/dev/hda:
Timing cached reads: 1164 MB in 2.00 seconds = 581.96 MB/sec
Timing buffered disk reads: 156 MB in 3.01 seconds = 51.79 MB/sec
/dev/hdb:
Timing cached reads: 1144 MB in 2.00 seconds = 571.96 MB/sec
Timing buffered disk reads: 162 MB in 3.01 seconds = 53.85 MB/sec
Didn't think it was that fast. I recall numbers in the 30s before.
> BTW, the pic link worked for me.
Yeah, it was only a temporary failure. He just caught it at a bad time.
-- -eben ebQenW1@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactarQ: What kind of modem did Jimi Hendrix use? A: A purple Hayes. ----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.
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