Hard Drive data rates

[Karl Larsen]

Dave Stevens wrote:
> On Friday 28 September 2007 10:50:32 am Karl Larsen wrote:
>   
>>     I was lead to mis-understand the data rate of my new SATA hard
>> drive. It indicated that the data rate was 3 GB/sec. But some checking
>> with Google said the Hard Drive makers are very free with their units.
>> To be specific a SATA drive is 3000 MegaBits/second. This boils down to
>> about 375 MB.
>>
>>     The old standard IDE parallel 40 pin plug is rated for a rate of 112
>> MB at the fastest to 78 GB at the slowest part of the platter. So in my
>> case I will not see a huge change moving to my SATA hard drive. I will
>> stay here on the new IDE much longer.
>>     
>
> I'd be very interested in seeing the command and output for that drive using 
> hdparm -iItT
>
>   
>> --
>>
>> 	Karl F. Larsen, AKA K5DI
>> 	Linux User
>> 	#450462   http://counter.li.org.
>>     
>
> Karl,
>
> I use a Seagate 320 gig ES SATA drive. This is a 3 Gb/sec drive BUT - it was 
> shipped with a jumper installed limiting it to half that rate, and this rate 
> is in any case a very optimistic one. Using hdparm as suggested consistently 
> gives me 78 MB/sec. That seems to be as good as it gets. Also this is a very 
> artificial figure, I have an old (about ten years) 9 gig SCSI drive that does 
> about half that. It seems that the recent addition of NCQ to SATA drives 
> makes more of an improvement in heavily loaded scenarios but quantifying this 
> is not simple or unambiguous. I want to try reconfiguring this setup in raid 
> 0 but won't be able to do so for a while. I know that another recent Seagate 
> drive, their 400G ATA gives transfer rates using hdparm -tT of about 50 
> MB/sec.
>
>   
There appears to be something wrong with hdparm on my computer. It only 
does this with all the various -tT and such:

[root at k5di /]# hdparm -iItT

hdparm - get/set hard disk parameters - version v6.9

Usage:  hdparm  [options] [device] ..

Options:
 -a   get/set fs readahead
 -A   set drive read-lookahead flag (0/1)
 -b   get/set bus state (0 == off, 1 == on, 2 == tristate)
 -B   set Advanced Power Management setting (1-255)
 -c   get/set IDE 32-bit IO setting
 -C   check IDE power mode status
 -d   get/set using_dma flag
 --direct  use O_DIRECT to bypass page cache for timings
 -D   enable/disable drive defect management
 -E   set cd-rom drive speed
 -f   flush buffer cache for device on exit
 -g   display drive geometry
 -h   display terse usage information
 -H   read temperature from drive (Hitachi only)
 -i   display drive identification
 -I   detailed/current information directly from drive
 --Istdin  read identify data from stdin as ASCII hex
 --Istdout write identify data to stdout as ASCII hex
 -k   get/set keep_settings_over_reset flag (0/1)
 -K   set drive keep_features_over_reset flag (0/1)
 -L   set drive doorlock (0/1) (removable harddisks only)
 -M   get/set acoustic management (0-254, 128: quiet, 254: fast) 
(EXPERIMENTAL)
 -m   get/set multiple sector count
 -n   get/set ignore-write-errors flag (0/1)
 -p   set PIO mode on IDE interface chipset (0,1,2,3,4,...)
 -P   set drive prefetch count
 -q   change next setting quietly
 -Q   get/set DMA tagged-queuing depth (if supported)
 -r   get/set device  readonly flag (DANGEROUS to set)
 -R   register an IDE interface (DANGEROUS)
 -s   set power-up in standby flag (0/1)
 -S   set standby (spindown) timeout
 -t   perform device read timings
 -T   perform cache read timings
 -u   get/set unmaskirq flag (0/1)
 -U   un-register an IDE interface (DANGEROUS)
 -v   defaults; same as -mcudkrag for IDE drives
 -V   display program version and exit immediately
 -w   perform device reset (DANGEROUS)
 -W   set drive write-caching flag (0/1) (DANGEROUS)
 -x   tristate device for hotswap (0/1) (DANGEROUS)
 -X   set IDE xfer mode (DANGEROUS)
 -y   put IDE drive in standby mode
 -Y   put IDE drive to sleep
 -Z   disable Seagate auto-powersaving mode
 -z   re-read partition table
 --security-help  display help for ATA security commands

    So I can't use this for some reason.



-- 

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.