Pendrive + USB 2.0 + slow transfer
 

I have a problem with my USB 2.0 (full speed) pendrive (mass storage). Data reading is of high transfer whereas data writing is very very slow. The problem is occurs only on machines with SATA disk where scsi_mod and sd_mod are compiled into kernel. It doesn't concern PCs with ATA disks where scsi_mod and sd_mod are compiled as modules.

Kernel: 2.6.20 (2.6.18 tested too)
dmesg:
usb 5-2.1: configuration #1 chosen from 1 choice
usbcore: registered new driver libusual
scsi_mod: exports duplicate symbol scsi_device_types (owned by kernel)
Initializing USB Mass Storage driver...
scsi4 : SCSI emulation for USB Mass Storage devices
usb-storage: device found at 7
usb-storage: waiting for device to settle before scanning
usbcore: registered new driver usb-storage
USB Mass Storage support registered.
Vendor: Corsair Model: Flash Voyager Rev: 1.00
Type: Direct-Access ANSI SCSI revision: 00
SCSI device sdb: 2002944 512-byte hdwr sectors (1026 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 26 00 00
sdb: assuming drive cache: write through
SCSI device sdb: 2002944 512-byte hdwr sectors (1026 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 26 00 00
sdb: assuming drive cache: write through
sdb: sdb1
sd 4:0:0:0: Attached scsi removable disk sdb
sd 4:0:0:0: Attached scsi generic sg1 type 0
usb-storage: device scan complete

lspci

00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express Memory Controller Hub (rev 03)
00:01.0 PCI bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express PCI Express Root Port (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 4 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02)
00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller (rev 02)
00:1f.2 SATA controller: Intel Corporation 82801GBM/GHM (ICH7 Family) Serial ATA Storage Controller AHCI (rev 02)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 02)
01:00.0 VGA compatible controller: nVidia Corporation GeForce Go 7400 (rev a1)
02:00.0 Ethernet controller: Agere Systems ET-131x PCI-E Ethernet Controller (rev 02)
05:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
06:00.0 CardBus bridge: Texas Instruments PCIxx12 Cardbus Controller
06:00.1 FireWire (IEEE 1394): Texas Instruments PCIxx12 OHCI Compliant IEEE 1394 Host Controller
06:00.2 Mass storage controller: Texas Instruments 5-in-1 Multimedia Card Reader (SD/MMC/MS/MS PRO/xD)
06:00.3 Class 0805: Texas Instruments PCIxx12 SDA Standard Compliant SD Host Controller

lsmod

Module Size Used by
usb_storage 66368 0
libusual 16080 1 usb_storage
pppoatm 6208 1
ppp_generic 26772 5 pppoatm
slhc 6528 1 ppp_generic
snd_seq_dummy 3844 0
snd_seq_oss 31744 0
snd_seq_midi_event 7168 1 snd_seq_oss
snd_seq 47504 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi_event
snd_seq_device 7884 3 snd_seq_dummy,snd_seq_oss,snd_seq
snd_pcm_oss 42272 0
snd_mixer_oss 16640 1 snd_pcm_oss
ipv6 233440 16
pcmcia 26056 0
pcmcia_core 38928 1 pcmcia
nls_utf8 2048 1
ntfs 193300 1
lp 11848 0
speedtch 13520 0
usbatm 17536 2 speedtch
atm 40020 4 pppoatm,usbatm
usbmouse 5568 0
usbhid 38240 0
nvidia 4715028 22
snd_hda_intel 18516 1
snd_hda_codec 142448 1 snd_hda_intel
snd_pcm 74312 3 snd_pcm_oss,snd_hda_intel,snd_hda_codec
snd_timer 23172 2 snd_seq,snd_pcm
snd 49956 12 snd_seq_dummy,snd_seq_oss,snd_seq,snd_seq_device,snd_pcm_oss,snd_mixer_oss,snd_hda_intel,snd_hda_cod ec,snd_pcm,snd_timer
ipw3945 171680 0
soundcore 9952 1 snd
snd_page_alloc 9800 2 snd_hda_intel,snd_pcm
ieee80211 44136 1 ipw3945
ieee80211_crypt 6528 1 ieee80211
intel_agp 21212 1
shpchp 33564 0
firmware_class 10240 2 speedtch,ipw3945
8250_pnp 8896 0
agpgart 32528 2 nvidia,intel_agp
ehci_hcd 28168 0
sg 30492 0
intel_rng 2752 0
evdev 9536 1
8250 21284 1 8250_pnp
parport_pc 36868 1
ide_cd 37572 0
uhci_hcd 22092 0
parport 34120 2 lp,parport_pc
cdrom 35872 1 ide_cd
usbcore 118852 9 usb_storage,libusual,speedtch,usbatm,usbmouse,usbhid,ehci_hcd,uhci_hcd
piix 9668 0 [permanent]
i2c_i801 7180 0
i2c_core 20880 2 nvidia,i2c_i801
ohci1394 32176 0
sdhci 16780 0
ieee1394 91576 1 ohci1394
serial_core 20480 1 8250
mmc_core 23760 1 sdhci
pci_hotplug 15944 1 shpchp
pcspkr 3008 0
serio_raw 6980 0


Any idea?

Ok, 'sync' in fstab was the problem:-)

Solved my problem as well it seems. Gotta love linux, come across plenty of hickups BUT (a big but - no pun intended) i have yet to come across anything i have not been able to solve. unlike that other
os where id be booting ghost once again :)

Why should sync cause such a drastic hit ?? anyone know.

It causes the drive to sync the data after every write ( so each packet of data is written individually ), so it will cause a drastic decrease in speed, with sync disabled the data is stored in a cache and written when a sync is called or you umnount the device cleanly, if you just pull the plug without sync then you might/will lose any recent data.

HTH