On 03/20/2015 01:36 PM, Joe Zeff wrote:
On 03/20/2015 12:25 PM, jd1008 wrote:
Man page says only choices are
u
and
m
Does not mention a - preceding either one.
Look at the usage you quoted, and I snipped. It lists -m, but not
simply m. In fact, I don't know off-hand of a command that allows you
to specify an option without either a single or double dash in front
of it.
What you say is weird!!
Here is that segment of the man page:
--user-master USER
Specifies which password (user/master) to select.
Defaults to user password. Only useful in combina‐
tion with --security-unlock, --security-set-pass,
--security-disable, --security-erase or --security-
erase-enhanced.
u user password
m master password
I do not see any hyphens preceding m or u
Also -m has a totally different usage effect:
-m Get/set sector count for multiple sector I/O on the
drive. A setting of 0 disables this feature. Mul‐
tiple 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, how‐
ever (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. West‐
ern 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 sup‐
ported by an installed drive (look for MaxMultSect in the
output). Some drives claim to support multi‐
ple mode, but lose data at some settings. Under rare
circumstances, such failures can result in mas‐
sive filesystem corruption.
Maybe you are using some other version???
My hdparm is
# rpm -q hdparm
hdparm-9.45-1.fc21.x86_64
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