Re: Why do not CRT/LCD monitors come with USB?

On Sun, 27 Jul 2008 20:20:00 UTC in comp.os.linux.hardware,
phil-news-nospam@xxxxxxxx wrote:

With Firewire,
the device become known to Linux a lot faster (1 or 2 seconds) than with USB
(8 to 15 seconds). It also runs faster (40 MBps vs. 25 MBps). That's with
USB at 480 mbps vs. Firewire at 400 mbps.

Does it actually run faster? I have a Seagate external drive here attached by
firewire and Linux is great with it (as long as I set the allow_restart option
in /sys/class/scsi_disk directory) but performance sucks:

[root ~]# hdparm -tT /dev/sda

/dev/sda:
Timing cached reads: 2016 MB in 2.00 seconds = 1007.81 MB/sec
Timing buffered disk reads: 68 MB in 3.02 seconds = 22.55 MB/sec

For a 2007/8 model drive that looks like 2003 performance numbers. Then on the
same machine I have a 2004 IDE drive in a USB case and this says

[root ~]# hdparm -tT /dev/sdb

/dev/sdb:
Timing cached reads: 1920 MB in 2.00 seconds = 959.45 MB/sec
Timing buffered disk reads: 82 MB in 3.04 seconds = 26.94 MB/sec

If I use the "Faster but buggy" serialize_io=0 option then the transfer rate on
firewire goes up to 23.3MB/sec and for only an extra 0.8MB/sec speed I'll stick
with "Slower but not so buggy" option :)

--
Trevor Hemsley, Brighton, UK
Trevor dot Hemsley at ntlworld dot com
.

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