I am evil :D
John Andersen wrote:
Continuing with this evil top posting.....
Your analogy is largely obsolete, as drive manufactures took steps to utilize the the surface uniformly years ago.
On Wednesday 08 December 2004 16:30, Yan-Fa Li wrote:
Think of an old fashioned 78RPM record player. The disc spins at a constant speed, 78RPM. The outer part of the disc is moving faster than the inner part, but the time the head has to read and write is the same regardless of where you are on the disc. Therefore the inner part gets data faster because it has to spin much less to read the same amount of data assuming all the tracks hold exactly the same amount.
I agree with you that the mapping information is now handled differently, i.e. that when I say track 80, sector 50, it's remapped internally to something different, but the principle of the example still hold true:
http://www.ntfs.com/hard-disk-basics.htm
Also if I do hdpart -t on each zone of a pair of 160GB hard disks I partitioned:
[EMAIL PROTECTED] root]# hdparm -t /dev/md1
/dev/md1: Timing buffered disk reads: 136 MB in 3.01 seconds = 45.18 MB/sec [EMAIL PROTECTED] root]# hdparm -t /dev/md2
/dev/md2: Timing buffered disk reads: 126 MB in 3.01 seconds = 41.86 MB/sec [EMAIL PROTECTED] root]# hdparm -t /dev/md3
/dev/md3: Timing buffered disk reads: 116 MB in 3.03 seconds = 38.28 MB/sec [EMAIL PROTECTED] root]# hdparm -t /dev/md4
/dev/md4: Timing buffered disk reads: 98 MB in 3.01 seconds = 32.56 MB/sec
Empirically that demonstrates that the principle is still valid. Inner parts of the disk perform at higher rates than the outer part. The result is valid on both the RAID partitions and the hard drives directly.
[EMAIL PROTECTED] root]# cat /proc/mdstat
Personalities : [raid1]
read_ahead 1024 sectors
md4 : active raid1 hdi4[0] hdk4[1]
40098176 blocks [2/2] [UU]md3 : active raid1 hdi3[0] hdk3[1]
39993728 blocks [2/2] [UU]md2 : active raid1 hdi2[0] hdk2[1]
39993728 blocks [2/2] [UU]md1 : active raid1 hdi1[0] hdk1[1]
39993664 blocks [2/2] [UU][EMAIL PROTECTED] root]# hdparm -i /dev/hdi
/dev/hdi:
Model=Maxtor 4R160L0, FwRev=RAMB1TU0, SerialNo=R4202E2E
Config={ Fixed }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
IORDY=on/off, tPIO={min:120,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 udma3 udma4 *udma5 udma6
AdvancedPM=yes: disabled (255) WriteCache=enabled
Drive conforms to: (null):* signifies the current active mode
Try this experiment for yourself. You'll see what I mean.
Yan
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