Why actual speed is slower than nominal? (2.6x vs 4x)
Hi there,
I am curious as to why the actual speed I get happens to be a lot
slower than the nominal one. I am using Knoppix 3.8.1 with 2.6.11
kernel in /dev/hdc, and the DVD writer is /dev/hdd
If I do not use "hdparm" to set the speed of /dev/hdd to udma2, then
actual speed happens to be even slower.
I am creating the image on the fly, could that make things go slower?
Below is the relevant information.
Thanks!
Konstantin
Writing: The File(s) Start Block 46
/dev/cdrom1: pre-formatting blank DVD+RW...
/dev/cdrom1: "Current Write Speed" is 4.1x1385KBps.
...
Max brk space used 0
2011265 extents written (3928 MB)
builtin_dd: 2011280*2KB out @ average 2.6x1385KBps
/dev/cdrom1: flushing cache
/dev/cdrom1: stopping de-icing
/dev/cdrom1: writing lead-out
dvd+rw-mediainfo /dev/cdrom1
INQUIRY: [LITE-ON ][DVDRW SOHW-1673S][JS07]
GET [CURRENT] CONFIGURATION:
Mounted Media: 1Ah, DVD+RW
Media ID: INFODISC/A10
Current Write Speed: 4.0x1385=5540KB/s
Write Speed #0: 4.0x1385=5540KB/s
GET [CURRENT] PERFORMANCE:
Write Performance: 4.0x1385=5540KB/s@[0 -> 0]
Speed Descriptor#0: 00/0 R@3.2x1385=4432KB/s W@4.0x1385=5540KB/s
READ DVD STRUCTURE[#0h]:
cadillac:~/kiev_backup>cat speed
Writing: The File(s) Start Block 46
/dev/cdrom1: pre-formatting blank DVD+RW...
/dev/cdrom1: "Current Write Speed" is 4.1x1385KBps.
...
Max brk space used 0
2011265 extents written (3928 MB)
builtin_dd: 2011280*2KB out @ average 2.6x1385KBps
/dev/cdrom1: flushing cache
/dev/cdrom1: stopping de-icing
/dev/cdrom1: writing lead-out
dvd+rw-mediainfo /dev/cdrom1
INQUIRY: [LITE-ON ][DVDRW SOHW-1673S][JS07]
GET [CURRENT] CONFIGURATION:
Mounted Media: 1Ah, DVD+RW
Media ID: INFODISC/A10
Current Write Speed: 4.0x1385=5540KB/s
Write Speed #0: 4.0x1385=5540KB/s
GET [CURRENT] PERFORMANCE:
Write Performance: 4.0x1385=5540KB/s@[0 -> 0]
Speed Descriptor#0: 00/0 R@3.2x1385=4432KB/s W@4.0x1385=5540KB/s
READ DVD STRUCTURE[#0h]:
Media Book Type: 92h, DVD+RW book [revision 2]
Legacy lead-out at: 2295104*2KB=4700372992
READ DISC INFORMATION:
Disc status: blank
Number of Sessions: 1
State of Last Session: empty
Number of Tracks: 1
READ TRACK INFORMATION[#1]:
Track State: blank
Track Start Address: 0*2KB
Free Blocks: 2295104*2KB
Track Size: 2295104*2KB
READ CAPACITY: 1*2048=2048
#hdparm -d1 -X 66 /dev/hdd
#hdparm -i /dev/hdd
/dev/hdd:
Model=LITE-ON DVDRW SOHW-1673S, FwRev=JS07, SerialNo=
Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=0kB, MaxMultSect=0
(maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
IORDY=yes, tPIO={min:227,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 *udma2
AdvancedPM=no
Drive conforms to: device does not report version:
* signifies the current active mode
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Reply to: