|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ATA Security Feature Set | FILES | BUGS | AUTHOR | SEE ALSO | COLOPHON |
|
|
|
HDPARM(8) System Manager's Manual HDPARM(8)
hdparm - get/set SATA/IDE device parameters
hdparm [options] [device ...]
hdparm provides a command line interface to various kernel
interfaces supported by the Linux SATA/PATA/SAS "libata" subsystem
and the older IDE driver subsystem. Many newer (2008 and later)
USB drive enclosures now also support "SAT" (SCSI-ATA Command
Translation) and therefore may also work with hdparm. E.g. recent
WD "Passport" models and recent NexStar-3 enclosures. Some
options may work correctly only with the latest kernels.
When no options are given, -acdgkmur is assumed. For "Get/set"
options, a query without the optional parameter (e.g. -d) will
query (get) the device state, and with a parameter (e.g., -d0)
will set the device state.
-a Get/set sector count for filesystem (software) read-ahead.
This is used to improve performance in sequential reads of
large files, by prefetching additional blocks in
anticipation of them being needed by the running task.
Many IDE drives also have a separate built-in read-ahead
function, which augments this filesystem (software) read-
ahead function.
-A Get/set the IDE drive´s read-lookahead feature (usually ON
by default). Usage: -A0 (disable) or -A1 (enable).
-b Get/set bus state.
-B Get/set Advanced Power Management feature, if the drive
supports it. A low value means aggressive power management
and a high value means better performance. Possible
settings range from values 1 through 127 (which permit
spin-down), and values 128 through 254 (which do not permit
spin-down). The highest degree of power management is
attained with a setting of 1, and the highest I/O
performance with a setting of 254. A value of 255 tells
hdparm to disable Advanced Power Management altogether on
the drive (not all drives support disabling it, but most
do).
-c Get/set (E)IDE 32-bit I/O support. A numeric parameter can
be used to enable/disable 32-bit I/O support. Currently
supported values include 0 to disable 32-bit I/O support, 1
to enable 32-bit data transfers, and 3 to enable 32-bit
data transfers with a special sync sequence required by
many chipsets. The value 3 works with nearly all 32-bit
IDE chipsets, but incurs slightly more overhead. Note that
"32-bit" refers to data transfers across a PCI or VLB bus
to the interface card only; all (E)IDE drives still have
only a 16-bit connection over the ribbon cable from the
interface card.
-C Check the current IDE power mode status, which will always
be one of unknown (drive does not support this command),
active/idle (normal operation), standby (low power mode,
drive has spun down), or sleeping (lowest power mode, drive
is completely shut down). The -S, -y, -Y, and -Z options
can be used to manipulate the IDE power modes.
-d Get/set 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.
--dco-freeze
DCO stands for Device Configuration Overlay, a way for
vendors to selectively disable certain features of a drive.
The --dco-freeze option will freeze/lock the current drive
configuration, thereby preventing software (or malware)
from changing any DCO settings until after the next power-
on reset.
--dco-identify
Query and dump information regarding drive configuration
settings which can be disabled by the vendor or OEM
installer. These settings show capabilities of the drive
which might be disabled by the vendor for "enhanced
compatibility". When disabled, they are otherwise hidden
and will not show in the -I identify output. For example,
system vendors sometimes disable 48_bit addressing on large
drives, for compatibility (and loss of capacity) with a
specific BIOS. In such cases, --dco-identify will show
that the drive is 48_bit capable, but -I will not show it,
and nor will the drive accept 48_bit commands.
--dco-restore
Reset all drive settings, features, and accessible
capacities back to factory defaults and full capabilities.
This command will fail if DCO is frozen/locked, or if a -Np
maximum size restriction has also been set. This is
EXTREMELY DANGEROUS and will very likely cause massive loss
of data. DO NOT USE THIS COMMAND.
--direct
Use the kernel´s "O_DIRECT" flag when performing a -t
timing test. This bypasses the page cache, causing the
reads to go directly from the drive into hdparm's buffers,
using so-called "raw" I/O. In many cases, this can produce
results that appear much faster than the usual page cache
method, giving a better indication of raw device and driver
performance.
--drq-hsm-error
VERY DANGEROUS, DON'T EVEN THINK ABOUT USING IT. This
option causes hdparm to issue an IDENTIFY command to the
kernel, but incorrectly marked as a "non-data" command.
This results in the drive being left with its
DataReQust(DRQ) line "stuck" high. This confuses the
kernel drivers, and may crash the system immediately with
massive data loss. The option exists to help in testing
and fortifying the kernel against similar real-world drive
malfunctions. VERY DANGEROUS, DO NOT USE!!
-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. Control of this feature
via the -D option is not supported for most modern drives
since ATA-4; thus this command may fail.
-E Set cd/dvd drive speed. This is NOT necessary for regular
operation, as the drive will automatically switch speeds on
its own. But if you want to play with it, just supply a
speed number after the option, usually a number like 2 or
4. This can be useful in some cases, though, to smooth out
DVD video playback.
-f Sync and flush the buffer cache for the device on exit.
This operation is also performed internally as part of the
-t and -T timings and other options.
--fallocate
This option currently works only on ext4 and xfs filesystem
types. When used, this must be the only option given. It
requires two parameters: the desired file size in kilo-
bytes (byte count divided by 1024), followed by the
pathname for the new file. It will create a new file of
the specified size, but without actually having to write
any data to the file. This will normally complete very
quickly, and without thrashing the storage device.
E.g. Create a 10KByte file: hdparm --fallocate 10 temp_file
--fibmap
When used, this must be the only option given. It requires
a file path as a parameter, and will print out a list of
the block extents (sector ranges) occupied by that file on
disk. Sector numbers are given as absolute LBA numbers,
referenced from sector 0 of the physical device rather than
from the partition or filesystem. This information can
then be used for a variety of purposes, such as examining
the degree of fragmenation of larger files, or determining
appropriate sectors to deliberately corrupt during fault-
injection testing procedures.
This option uses the new FIEMAP (file extent map) ioctl()
when available, and falls back to the older FIBMAP (file
block map) ioctl() otherwise. Note that FIBMAP suffers
from a 32-bit block-number interface, and thus not work
beyond 8TB or 16TB. FIBMAP is also very slow, and does not
deal well with preallocated uncommitted extents in ext4/xfs
filesystems, unless a sync() is done before using this
option.
--fwdownload
When used, this should be the only option given. It
requires a file path immediately after the option,
indicating where the new drive firmware should be read
from. The contents of this file will be sent to the drive
using the (S)ATA DOWNLOAD MICROCODE command, using either
transfer protocol 7 (entire file at once), or, if the drive
supports it, transfer protocol 3 (segmented download).
This command is EXTREMELY DANGEROUS and could destroy both
the drive and all data on it. DO NOT USE THIS COMMAND.
The --fwdownload-mode3 , --fwdownload-mode3-max , and
--fwdownload-mode7 variations on basic --fwdownload allow
overriding automatic protocol detection in favour of
forcing hdparm to use a specific transfer protocol, for
testing purposes only.
-F Flush the on-drive write cache buffer (older drives may not
implement this).
-g Display the drive geometry (cylinders, heads, sectors), the
size (in sectors) of the device, and the starting offset
(in sectors) of the device from the beginning of the drive.
-h Display terse usage information (help).
-H Read the temperature from some (mostly Hitachi) drives.
Also reports if the temperature is within operating
condition range (this may not be reliable). Does not cause
the drive to spin up if idle.
-i Display the identification info which the kernel drivers
(IDE, libata) have stored from boot/configuration time.
This may differ from the current information obtainable
directly from the drive itself with the -I option. The
data returned may or may not be current, depending on
activity since booting the system. 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, and later
editions.
--idle-immediate
Issue an ATA IDLE_IMMEDIATE command, to put the drive into
a lower power state. Usually the device remains spun-up.
--idle-unload
Issue an ATA IDLE_IMMEDIATE_WITH_UNLOAD command, to unload
or park the heads and put the drive into a lower power
state. Usually the device remains spun-up.
-I Request identification info directly from the drive, which
is displayed in a new expanded format with considerably
more detail than with the older -i option.
--Iraw <pathname>
This option dumps the drive's identify data in raw binary
to the specified file.
--Istdin
This is a special 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. When --Istdin is used, it must be the *only*
parameter given.
--Istdout
This option dumps the drive's identify data in hex to
stdout, in a format similar to that from
/proc/ide/*/identify, and suitable for later use with the
--Istdin option.
-J Get/set the Western Digital (WD) Green Drive's "idle3"
timeout value. This timeout controls how often the drive
parks its heads and enters a low power consumption state.
The factory default is eight (8) seconds, which is a very
poor choice for use with Linux. Leaving it at the default
will result in hundreds of thousands of head load/unload
cycles in a very short period of time. The drive mechanism
is only rated for 300,000 to 1,000,000 cycles, so leaving
it at the default could result in premature failure, not to
mention the performance impact of the drive often having to
wake-up before doing routine I/O.
WD supply a WDIDLE3.EXE DOS utility for tweaking this
setting, and you should use that program instead of hdparm
if at all possible. The reverse-engineered implementation
in hdparm is not as complete as the original official
program, even though it does seem to work on at a least a
few drives. A full power cycle is required for any change
in setting to take effect, regardless of which program is
used to tweak things.
A setting of 30 seconds is recommended for Linux use.
Permitted values are from 8 to 12 seconds, and from 30 to
300 seconds in 30-second increments. Specify a value of
zero (0) to disable the WD idle3 timer completely (NOT
RECOMMENDED!).
-k Get/set the "keep_settings_over_reset" flag for the drive.
When this flag is set, the drive will preserve the -dmu
settings over a soft reset, (as done during the error
recovery sequence). This option defaults to off, to
prevent drive reset loops which could be caused by
combinations of -dmu settings. The -k option should
therefore only be set after one has achieved confidence in
correct system operation with a chosen set of configuration
settings. In practice, all that is typically necessary to
test a configuration (prior to using -k) is to verify that
the drive can be read/written, and that no error logs
(kernel messages) are generated in the process (look in
/var/log/messages on most systems).
-K Set the drive´s "keep_features_over_reset" flag. Setting
this enables the drive to retain the settings for -APSWXZ
over a soft reset (as done during the error recovery
sequence). Not all drives support this feature.
-L Set the drive´s doorlock flag. Setting this to 1 will lock
the door mechanism of some removable hard drives (e.g.
Syquest, ZIP, Jazz..), and setting it to 0 will unlock the
door mechanism. Normally, Linux maintains the door locking
mechanism automatically, depending on drive usage (locked
whenever a filesystem is mounted). But on system shutdown,
this can be a nuisance if the root partition is on a
removable disk, since the root partition is left mounted
(read-only) after shutdown. So, by using this command to
unlock the door after the root filesystem is remounted
read-only, one can then remove the cartridge from the drive
after shutdown.
-m Get/set sector count for multiple sector I/O on the drive.
A setting of 0 disables this feature. Multiple sector mode
(aka IDE Block Mode), is a feature of most modern IDE hard
drives, permitting the transfer of multiple sectors per I/O
interrupt, rather than the usual one sector per interrupt.
When this feature is enabled, it typically reduces
operating system overhead for disk I/O by 30-50%. On many
systems, it also provides increased data throughput of
anywhere from 5% to 50%. Some drives, however (most
notably the WD Caviar series), seem to run slower with
multiple mode enabled. Your mileage may vary. Most drives
support the minimum settings of 2, 4, 8, or 16 (sectors).
Larger settings may also be possible, depending on the
drive. A setting of 16 or 32 seems optimal on many
systems. Western Digital recommends lower settings of 4 to
8 on many of their drives, due tiny (32kB) drive buffers
and non-optimized buffering algorithms. The -i option can
be used to find the maximum setting supported by an
installed drive (look for MaxMultSect in the output). Some
drives claim to support multiple mode, but lose data at
some settings. Under rare circumstances, such failures can
result in massive filesystem corruption.
--make-bad-sector
Deliberately create a bad sector (aka. "media error") on
the disk. EXCEPTIONALLY DANGEROUS. DO NOT USE THIS
OPTION!! This can be useful for testing of device/RAID
error recovery mechanisms. The sector number is given as a
(base10) parameter after the option. Depending on the
device, hdparm will choose one of two possible ATA commands
for corrupting the sector. The WRITE_LONG works on most
drives, but only up to the 28-bit sector boundary. Some
very recent drives (2008) may support the new
WRITE_UNCORRECTABLE_EXT command, which works for any LBA48
sector. If available, hdparm will use that in preference
to WRITE_LONG. The WRITE_UNCORRECTABLE_EXT command itself
presents a choice of how the new bad sector should behave.
By default, it will look like any other bad sector, and the
drive may take some time to retry and fail on subsequent
READs of the sector. However, if a single letter f is
prepended immediately in front of the first digit of the
sector number parameter, then hdparm will issue a "flagged"
WRITE_UNCORRECTABLE_EXT, which causes the drive to merely
flag the sector as bad (rather than genuinely corrupt it),
and subsequent READs of the sector will fail immediately
(rather than after several retries). Note also that the
--repair-sector option can be used to restore (any) bad
sectors when they are no longer needed, including sectors
that were genuinely bad (the drive will likely remap those
to a fresh area on the media).
-M Get/set Automatic Acoustic Management (AAM) setting. Most
modern harddisk drives have the ability to speed down the
head movements to reduce their noise output. The possible
values are between 0 and 254. 128 is the most quiet (and
therefore slowest) setting and 254 the fastest (and
loudest). Some drives have only two levels (quiet / fast),
while others may have different levels between 128 and 254.
At the moment, most drives only support 3 options, off,
quiet, and fast. These have been assigned the values 0,
128, and 254 at present, respectively, but integer space
has been incorporated for future expansion, should this
change.
-n Get or set the "ignore_write_errors" flag in the driver.
Do NOT play with this without grokking the driver source
code first.
-N Get/set max visible number of sectors, also known as the
Host Protected Area setting. Without a parameter, -N
displays the current setting, which is reported as two
values: the first gives the current max sectors setting,
and the second shows the native (real) hardware limit for
the disk. The difference between these two values
indicates how many sectors of the disk are currently hidden
from the operating system, in the form of a Host Protected
Area (HPA). This area is often used by computer makers to
hold diagnostic software, and/or a copy of the originally
provided operating system for recovery purposes. Another
possible use is to hide the true capacity of a very large
disk from a BIOS/system that cannot normally cope with
drives of that size (eg. most current {2010} BIOSs cannot
deal with drives larger than 2TB, so an HPA could be used
to cause a 3TB drive to report itself as a 2TB drive). To
change the current max (VERY DANGEROUS, DATA LOSS IS
EXTREMELY LIKELY), a new value should be provided (in
base10) immediately following the -N option. This value is
specified as a count of sectors, rather than the "max
sector address" of the drive. Drives have the concept of a
temporary (volatile) setting which is lost on the next
hardware reset, as well as a more permanent (non-volatile)
value which survives resets and power cycles. By default,
-N affects only the temporary (volatile) setting. To
change the permanent (non-volatile) value, prepend a
leading p character immediately before the first digit of
the value. Drives are supposed to allow only a single
permanent change per session. A hardware reset (or power
cycle) is required before another permanent -N operation
can succeed. Note that any attempt to set this value may
fail if the disk is being accessed by other software at the
same time. This is because setting the value requires a
pair of back-to-back drive commands, but there is no way to
prevent some other command from being inserted between them
by the kernel. So if it fails initially, just try again.
Kernel support for -N is buggy for many adapter types
across many kernel versions, in that an incorrect (too
small) max size value is sometimes reported. As of the
2.6.27 kernel, this does finally seem to be working on most
hardware.
--offset
Offsets to given number of GiB (1024*1024*1024) when
performing -t timings of device reads. Speed changes
(about twice) along many mechanical drives. Usually the
maximum is at the beginning, but not always. Solid-state
drives (SSDs) should show similar timings regardless of
offset.
-p Attempt to reprogram the IDE interface chipset for the
specified PIO mode, or attempt to auto-tune for the "best"
PIO mode supported by the drive. This feature is supported
in the kernel for only a few "known" chipsets, and even
then the support is iffy at best. Some IDE chipsets are
unable to alter the PIO mode for a single drive, in which
case this option may cause the PIO mode for both drives to
be set. Many IDE chipsets support either fewer or more
than the standard six (0 to 5) PIO modes, so the exact
speed setting that is actually implemented will vary by
chipset/driver sophistication. Use with extreme caution!
This feature includes zero protection for the unwary, and
an unsuccessful outcome may result in severe filesystem
corruption!
-P Set the maximum sector count for the drive´s internal
prefetch mechanism. Not all drives support this feature,
and it was dropped from the official spec as of ATA-4.
--prefer-ata12
When using the SAT (SCSI ATA Translation) protocol, hdparm
normally prefers to use the 16-byte command format whenever
possible. But some USB drive enclosures don't work
correctly with 16-byte commands. This option can be used
to force use of the smaller 12-byte command format with
such drives. hdparm will still revert to 16-byte commands
for things that cannot be done with the 12-byte format
(e.g. sector accesses beyond 28-bits).
-q Handle the next option quietly, suppressing normal output
(but not error messages). This is useful for reducing
screen clutter when running from system startup scripts.
Not applicable to the -i or -v or -t or -T options.
-Q Get or set the device's command queue_depth, if supported
by the hardware. This only works with 2.6.xx (or later)
kernels, and only with device and driver combinations which
support changing the queue_depth. For SATA disks, this is
the Native Command Queuing (NCQ) queue depth.
-r Get/set read-only flag for the device. When set, Linux
disallows write operations on the device.
-R Get/set Write-Read-Verify feature, if the drive supports
it. Usage: -R0 (disable) or -R1 (enable). This feature is
intended to have the drive firmware automatically read-back
any data that is written by software, to verify that the
data was successfully written. This is generally overkill,
and can slow down disk writes by as much as a factor of two
(or more).
--read-sector
Reads from the specified sector number, and dumps the
contents in hex to standard output. The sector number must
be given (base10) after this option. hdparm will issue a
low-level read (completely bypassing the usual block layer
read/write mechanisms) for the specified sector. This can
be used to definitively check whether a given sector is bad
(media error) or not (doing so through the usual mechanisms
can sometimes give false positives).
--repair-sector
This is an alias for the --write-sector option. VERY
DANGEROUS.
-s Enable/disable the power-on in standby feature, if
supported by the drive. VERY DANGEROUS. Do not use unless
you are absolutely certain that both the system BIOS (or
firmware) and the operating system kernel (Linux >= 2.6.22)
support probing for drives that use this feature. When
enabled, the drive is powered-up in the standby mode to
allow the controller to sequence the spin-up of devices,
reducing the instantaneous current draw burden when many
drives share a power supply. Primarily for use in large
RAID setups. This feature is usually disabled and the
drive is powered-up in the active mode (see -C above).
Note that a drive may also allow enabling this feature by a
jumper. Some SATA drives support the control of this
feature by pin 11 of the SATA power connector. In these
cases, this command may be unsupported or may have no
effect.
-S Put the drive into idle (low-power) mode, and also set the
standby (spindown) timeout for the drive. This timeout
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.
-t Perform timings of device reads for benchmark and
comparison purposes. For meaningful results, this
operation should be repeated 2-3 times on an otherwise
inactive system (no other active processes) with at least a
couple of megabytes of free memory. This displays the
speed of reading through the buffer cache to the disk
without any prior caching of data. This measurement is an
indication of how fast the drive can sustain sequential
data reads under Linux, without any filesystem overhead.
To ensure accurate measurements, the buffer cache is
flushed during the processing of -t using the BLKFLSBUF
ioctl.
-T Perform timings of cache reads for benchmark and comparison
purposes. For meaningful results, this operation should be
repeated 2-3 times on an otherwise inactive system (no
other active processes) with at least a couple of megabytes
of free memory. This displays the speed of reading
directly from the Linux buffer cache without disk access.
This measurement is essentially an indication of the
throughput of the processor, cache, and memory of the
system under test.
--trim-sector-ranges
For Solid State Drives (SSDs). EXCEPTIONALLY DANGEROUS. DO
NOT USE THIS OPTION!! Tells the drive firmware to discard
unneeded data sectors, destroying any data that may have
been present within them. This makes those sectors
available for immediate use by the firmware's garbage
collection mechanism, to improve scheduling for wear-
leveling of the flash media. This option expects one or
more sector range pairs immediately after the option: an
LBA starting address, a colon, and a sector count (max
65535), with no intervening spaces. EXCEPTIONALLY
DANGEROUS. DO NOT USE THIS OPTION!!
E.g. hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz
--trim-sector-ranges-stdin
Identical to --trim-sector-ranges above, except the list of
lba:count pairs is read from stdin rather than being
specified on the command line. This can be used to avoid
problems with excessively long command lines. It also
permits batching of many more sector ranges into single
commands to the drive, up to the currently configured
transfer limit (max_sectors_kb).
-u Get/set the interrupt-unmask flag for the drive. A setting
of 1 permits the driver to unmask other interrupts during
processing of a disk interrupt, which greatly improves
Linux´s responsiveness and eliminates "serial port overrun"
errors. Use this feature with caution: some
drive/controller combinations do not tolerate the increased
I/O latencies possible when this feature is enabled,
resulting in massive filesystem corruption. In particular,
CMD-640B and RZ1000 (E)IDE interfaces can be unreliable
(due to a hardware flaw) when this option is used with
kernel versions earlier than 2.0.13. Disabling the IDE
prefetch feature of these interfaces (usually a BIOS/CMOS
setting) provides a safe fix for the problem for use with
earlier kernels.
-v Display some basic settings, similar to -acdgkmur for IDE.
This is also the default behaviour when no options are
specified.
-V Display program version and exit immediately.
--verbose
Display extra diagnostics from some commands.
-w Perform a device reset (DANGEROUS). Do NOT use this
option. It exists for unlikely situations where a reboot
might otherwise be required to get a confused drive back
into a useable state.
--write-sector
Writes zeros to the specified sector number. VERY
DANGEROUS. The sector number must be given (base10) after
this option. hdparm will issue a low-level write
(completely bypassing the usual block layer read/write
mechanisms) to the specified sector. This can be used to
force a drive to repair a bad sector (media error).
-W Get/set the IDE/SATA drive´s write-caching feature.
-X Set the IDE transfer mode for (E)IDE/ATA drives. This is
typically used in combination with -d1 when enabling DMA
to/from a drive on a supported 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 option 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 option) 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.
-y Force an IDE drive to immediately enter the low power
consumption standby mode, usually causing it to spin down.
The current power mode status can be checked using the -C
option.
-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 option.
-z Force a kernel re-read of the partition table of the
specified device(s).
-Z Disable the automatic power-saving function of certain
Seagate drives (ST3xxx models?), to prevent them from
idling/spinning-down at inconvenient times.
These switches are DANGEROUS to experiment with, and might not
work with some kernels. USE AT YOUR OWN RISK.
--security-help
Display terse usage info for all of the --security-*
options.
--security-freeze
Freeze the drive´s security settings. The drive does not
accept any security commands until next power-on reset.
Use this function in combination with --security-unlock to
protect drive from any attempt to set a new password. Can
be used standalone, too. No other options are permitted on
the command line with this one.
--security-prompt-for-password
Prompt for the --security PWD rather than getting from the
command line args. This avoids having passwords show up in
shell history or in /proc/self/cmdline during execution.
--security-unlock PWD
Unlock the drive, using password PWD. Password is given as
an ASCII string and is padded with NULs to reach 32 bytes.
The applicable drive password is selected with the --user-
master switch (default is "user" password). No other
options are permitted on the command line with this one.
--security-set-pass PWD
Lock the drive, using password PWD (Set Password)
(DANGEROUS). Password is given as an ASCII string and is
padded with NULs to reach 32 bytes. Use the special
password NULL to set an empty password. The applicable
drive password is selected with the --user-master switch
(default is "user" password) and the applicable security
mode with the --security-mode switch. No other options are
permitted on the command line with this one.
--security-disable PWD
Disable drive locking, using password PWD. Password is
given as an ASCII string and is padded with NULs to reach
32 bytes. The applicable drive password is selected with
the --user-master switch (default is "user" password). No
other options are permitted on the command line with this
one.
--security-erase PWD
Erase (locked) drive, using password PWD (DANGEROUS).
Password is given as an ASCII string and is padded with
NULs to reach 32 bytes. Use the special password NULL to
represent an empty password. The applicable drive password
is selected with the --user-master switch (default is
"user" password). No other options are permitted on the
command line with this one.
--security-erase-enhanced PWD
Enhanced erase (locked) drive, using password PWD
(DANGEROUS). Password is given as an ASCII string and is
padded with NULs to reach 32 bytes. The applicable drive
password is selected with the --user-master switch (default
is "user" password). No other options are permitted on the
command line with this one.
--user-master USER
Specifies which password (user/master) to select. Defaults
to user password. Only useful in combination with
--security-unlock, --security-set-pass, --security-disable,
--security-erase or --security-erase-enhanced.
u user password
m master password
--security-mode MODE
Specifies which security mode (high/maximum) to set.
Defaults to high. Only useful in combination with
--security-set-pass.
h high security
m maximum security
THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT
YOUR OWN RISK.
/etc/hdparm.conf
As noted above, the -m sectcount and -u 1 options should be used
with caution at first, preferably on a read-only filesystem. Most
drives work well with these features, but a few drive/controller
combinations are not 100% compatible. Filesystem corruption may
result. Backup everything before experimenting!
Some options (e.g. -r for SCSI) may not work with old kernels as
necessary ioctl()´s were not supported.
Although this utility is intended primarily for use with SATA/IDE
hard disk devices, several of the options are also valid (and
permitted) for use with SCSI hard disk devices and MFM/RLL hard
disks with XT interfaces.
The Linux kernel up until 2.6.12 (and probably later) doesn´t
handle the security unlock and disable commands gracefully and
will segfault and in some cases even panic. The security commands
however might indeed have been executed by the drive. This poor
kernel behaviour makes the PIO data security commands rather
useless at the moment.
Note that the "security erase" and "security disable" commands
have been implemented as two consecutive PIO data commands and
will not succeed on a locked drive because the second command will
not be issued after the segfault. See the code for hints how
patch it to work around this problem. Despite the segfault it is
often still possible to run two instances of hdparm consecutively
and issue the two necessary commands that way.
hdparm has been written by Mark Lord <[email protected]>, the
original primary developer and maintainer of the (E)IDE driver for
Linux, and current contributor to the libata subsystem, along with
suggestions and patches from many netfolk.
The disable Seagate auto-powersaving code is courtesy of Tomi
Leppikangas([email protected]).
Security freeze command by Benjamin Benz, 2005.
PIO data out security commands by Leonard den Ottolander, 2005.
Some other parts by Benjamin Benz and others.
http://www.t13.org/ Technical Committee T13 AT Attachment
(ATA/ATAPI) Interface.
http://www.serialata.org/ Serial ATA International Organization.
http://www.compactflash.org/ CompactFlash Association.
This page is part of the hdparm (get/set ATA/SATA drive parameters
under Linux) project. Information about the project can be found
at ⟨http://hdparm.sourceforge.net/⟩. It is not known how to
report bugs for this man page; if you know, please send a mail to
[email protected]. This page was obtained from the tarball
hdparm-9.56.tar.gz fetched from
⟨http://sourceforge.net/projects/hdparm/files/latest/download?source=dlp⟩
on 2025-08-11. If you discover any rendering problems in this
HTML version of the page, or you believe there is a better or more
up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Version 9.55 March 2018 HDPARM(8)
Pages that refer to this page: fsync(2), proc(5), proc_ide(5)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|