Gentoo Archives: gentoo-user

From: Grant <emailgrant@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] {OT} USB 3.0 hard drive speed test
Date: Thu, 11 Aug 2011 18:29:06
Message-Id: CAN0CFw2zXAbqKfnr5mfRnzwdKK40KHa+gPLq4ngAp4HhVoku=A@mail.gmail.com
In Reply to: Re: [gentoo-user] {OT} USB 3.0 hard drive speed test by Mark Knecht
1 >> I'm testing this USB 3.0 bus-powered hard drive:
2 >>
3 >> http://www.amazon.com/gp/product/B0041OSQ9S
4 >>
5 >> and I get:
6 >>
7 >> # hdparm -tT /dev/sdb
8 >> /dev/sdb:
9 >> Timing cached reads:   8006 MB in  2.00 seconds = 4004.33 MB/sec
10 >> Timing buffered disk reads: 252 MB in  3.01 seconds =  83.63 MB/sec
11 >>
12 >> # hdparm -tT /dev/sdb
13 >> /dev/sdb:
14 >> Timing cached reads:   8230 MB in  2.00 seconds = 4116.54 MB/sec
15 >> Timing buffered disk reads: 252 MB in  3.02 seconds =  83.55 MB/sec
16 >>
17 >> # hdparm -tT /dev/sdb
18 >> /dev/sdb:
19 >> Timing cached reads:   8446 MB in  2.00 seconds = 4224.36 MB/sec
20 >> Timing buffered disk reads: 230 MB in  3.02 seconds =  76.28 MB/sec
21 >>
22 >> Wikipedia says USB 3.0 has transmission speeds of up to 5 Gbit/s.
23 >> Doesn't MB/sec denote mega*bytes* per second?
24 >>
25 >> - Grant
26 >
27 > 4000MB/s = 4Gb/s
28
29 OK, I thought "B" designated bytes and "b" designated bits. So when
30 you see something like MB/s or Mb/s there's no way to know if it's
31 referring to megabits or megabytes?
32
33 - Grant

Replies

Subject Author
Re: [gentoo-user] {OT} USB 3.0 hard drive speed test Mark Knecht <markknecht@×××××.com>
Re: [gentoo-user] {OT} USB 3.0 hard drive speed test Alan McKinnon <alan.mckinnon@×××××.com>