Hdparm: differenze tra le versioni

; -d : Disable/enable the "using_dma" flag for this drive.  This option now works with most combinations of drives and PCI interfaces which support DMA and which are known to the kernel IDE driver.  It is also a good idea to use the appropriate -X option in combination with -d1 to ensure that the  drive itself is programmed for the correct DMA mode, although most BIOSs should do this for you at boot time.  Using DMA nearly always gives the best performance, with fast I/O throughput and low CPU usage.  But there are at least a few configurations of chipsets and drives for  which  DMA  does  not make much of a difference, or may even slow things down (on really messed up hardware!).  Your mileage may vary.

; -D : Enable/disable the on-drive defect management feature, whereby the drive firmware tries to automatically manage defective sectors by relocating them to "spare" sectors reserved by the factory for such.

; -f : Sincronizza ed esegue un flush del buffer del dispositibo. Viene eseguito anche dutante i test '''-T''' e '''-t'''

;-i : Display the identification info that was obtained from the drive at boot time, if available.  This is a feature of modern IDE drives, and may not be supported by older devices.  The data returned may or may not be current, depending on activity since booting the system.  However, the current multiple sector mode count is always shown.  For a more detailed interpretation of the identification info, refer to AT Attachment Interface for Disk Drives (ANSI ASC X3T9.2 working draft, revision 4a, April 19/93).

; -Istdin : This is a special "no seatbelts" variation on the -I option, which accepts a drive identification  block  as  standard  input  instead  of  using  a /dev/hd*  parameter. The  format of this block must be exactly the same as that found in the /proc/ide/*/hd*/identify "files", or that produced by the '''-Istdout''' option described below.  This variation is designed for use with collected "libraries" of drive  identification  information,  and  can also be used on ATAPI drives which may give media errors with the standard mechanism.

; -Istdout : This  option  simply  dumps the identify data in hex to stdout, in a format similar to that from /proc/, and suitable for later use with the -Istdin option.

; -q : Handle  the next flag quietly, suppressing normal output.  This is useful for reducing screen clutter when running from system startup scripts.  Not applicable to the -i or -v or -t or -T flags.

; -Q : Set tagged queue depth (1 or greater), or turn tagged queuing off (0).  This only works with the newer 2.5.xx (or later) kernels, and only with  the few drives that currently support it.

; -R : Register an IDE interface.  Dangerous.  See the -U option for more information.

; -S : Set  the  standby  (spindown)  timeout  for the drive.  This value is used by the drive to determine how long to wait (with no disk activity) before turning off the spindle motor to save power.  Under such circumstances, the drive may take as long as 30 seconds to respond  to  a  subsequent  disk access,  though  most  drives  are  much quicker.  The encoding of the timeout value is somewhat peculiar.  A value of zero means "timeouts are disabled": the device will not automatically enter standby mode.  Values from 1 to 240 specify multiples of 5 seconds, yielding timeouts from 5 seconds to  20  minutes.  Values  from 241 to 251 specify from 1 to 11 units of 30 minutes, yielding timeouts from 30 minutes to 5.5 hours.  A value of 252 signifies a timeout of 21 minutes. A value of 253 sets a vendor-defined timeout period between 8 and 12 hours, and the value 254 is  reserved.  255 is interpreted as 21 minutes plus 15 seconds.  Note that some older drives may have very different interpretations of these values.

; -W : Disable/enable the IDE drive's write-caching feature (default state is undeterminable; manufacturer/model specific).

; -X :    Set  the  IDE transfer mode for newer (E)IDE/ATA drives.  This is typically used in combination with -d1 when enabling DMA to/from a drive on a sup ported interface chipset, where -X mdma2 is used to select multiword DMA mode2 transfers and -X sdma1 is used to select simple mode 1 DMA transfers. With  systems  which  support  UltraDMA  burst  timings, -X udma2 is used to select UltraDMA mode2 transfers (you'll need to prepare the chipset for UltraDMA beforehand).  Apart from that, use of this flag is seldom necessary since most/all modern IDE drives default to their fastest PIO  transfer mode  at  power-on.  Fiddling with this can be both needless and risky.  On drives which support alternate transfer modes, -X can be used to switch the mode of the drive only.  Prior to changing the transfer mode, the IDE interface should be jumpered or programmed (see -p flag) for the new  mode setting  to  prevent  loss  and/or corruption of data.  Use this with extreme caution!  For the PIO (Programmed Input/Output) transfer modes used by Linux, this value is simply the desired PIO mode number plus 8.  Thus, a value of 09 sets PIO mode1, 10 enables PIO mode2, and 11 selects PIO mode3. Setting  00  restores  the drive's "default" PIO mode, and 01 disables IORDY.  For multiword DMA, the value used is the desired DMA mode number plus 32.  for UltraDMA, the value is the desired UltraDMA mode number plus 64.

:** '''0''' -X08 3.3MB/sec

:** '''1''' -X09 5.2MB/sec

:** '''3''' -X11 11.1MB/sec

:** '''4''' -X12 16.7MB/sec  

:** '''0''' 2.1MB/sec

:** '''1''' 4.2MB/sec

:** '''2''' 8.3MB/sec  

:** '''0''' -X32 4.2MB/sec

:** '''1''' -X33 13.3MB/sec

:** '''2''' -X34 16.6MB/sec  

:** '''0''' 16MB/sec

:** '''1''' 25MB/sec

:** '''4''' -X68 66MB/sec UDMA66

:** '''5''' -x69 100MB/sec UDMA100  

; -Y : Force  an  IDE  drive  to  immediately  enter  the lowest power consumption sleep mode, causing it to shut down completely.  A hard or soft reset is required before the drive can be accessed again (the Linux IDE driver will automatically handle issuing a reset if/when needed).  The current  power mode status can be checked using the -C flag.

; -z : Forza la rilettura della tabella delle partizioni, utile nel caso di modifiche con ''fdisk'' o simili, senza rendere necessario un riavvio della macchina.