From Wikipedia, the free encyclopedia
The Microdrive is a brand name for a miniature, 1-inch hard
disk designed to fit in a CompactFlash (CF) Type II slot. The
release of similar drives by other makers has led to them often
being referred to as 'microdrives'. However, 'microdrive' is not a
genericized trademark[1] and
manufacturers other than IBM up to
2003 and Hitachi after do not officially refer to
these drives as Microdrives. Some other companies such as Sony have licensed the name and sell
re-branded versions, others such as Seagate have their own designs which
fit in the same form factor.
These drives fit into any CompactFlash II
slot; however, they may consume more power than flash memory
(currents on the order of 190 mA, peak 310 mA, at 3.3 V) and
therefore may not work in some low-power devices (e.g. handheld
computers). Nevertheless, they have some benefits over flash memory
in terms of the way data is stored and manipulated. Microdrives can
store 8 GB or more, but
must be formatted for a file system which supports this capacity,
such as ext3 or NTFS which might not be supported by older CompactFlash hosts.
To avoid this problem, the operating system may partition a drive
so that each filesystem is smaller than 4Gb.
History
The Microdrive was developed and launched in 1999 by IBM with a
capacity of 170 MB,
which was expanded to 8 GB by 2006. They weigh about 16 g
(~1/2 oz), with dimensions
of 42.8×36.4×5 mm (1.7×1.4×.2 in). These were the
smallest hard drives in the world at the time. From 1999 to 2003
they were known as IBM Microdrives, and from 2003
as Hitachi Microdrives, when Hitachi bought IBM's
hard drive division. Microdrive was a registered trademark by IBM and Hitachi for each
period.
IBM initially released a 170 MB and 340 MB model. The next year
512 MB and 1 GB models were announced and became available. In December 2002
Hitachi bought IBM's disk drive business, including the Microdrive
technology and brand. By 2003, under Hitachi, bigger 2 GB models
came out. Over the years, even larger sizes have become available.
There are licensed branded Sony models called Sony Microdrive;
these are re-badged Hitachi made models.
Seagate 2.5 GB 1" CF Drive
In 2004 Seagate launched 2.5 and 5 GB models as well,
and tends to refer to them as either 1-inch hard drives, or
CompactFlash hard drives due to the trademark issue. In 2005 it
launched an 8 GB model as well.
Recently a Chinese manufacturer called GS Magic started
marketing small form factor HDDs for CF; it has, however, been sued
by Hitachi for patent infringement of the IBM design [1] (as opposed to
Seagate, which used its own technology). These drives are generally
cheaper and of lower quality than Hitachi and Seagate drives and
have received a plethora of bad reviews.*
- A link to the product announcement [2], but as of yet,
The company's website is down, the US distributor said they went
out of business in 02/07, and no mention of the lawsuit or the
reviews has been found.
Microdrive models by
timeline
Date of release of large sizes.
| 1999 |
170 megabyte (IBM
MD170/A) |
| 1999 |
340 megabyte (IBM) |
| 2000 |
512 megabyte, 1 gigabyte (IBM) |
| 2003 |
2 gigabytes (Hitachi) |
| 2004 |
4 gigabytes (Hitachi), 2.5 and 5 gigabytes (Seagate) |
| 2005 |
6 gigabytes (Hitachi), 8 gigabytes (Seagate) |
| 2006 |
8 gigabytes (Hitachi), 8 gigabytes (Seagate) |
| 2007 |
Hitachi alluded to the possible availability of a 20-gigabyte
microdrive [2].
As of October 2009, this high-capacity drive is commercially
unavailable.[3] |
| 2008 |
8 gigabytes (Hitachi), 8 gigabytes (Seagate) |
Availability
As of 2006 the most
commonly-seen microdrives are the smaller sizes, up to 1GB. Larger
(2GB to 8GB) drives, such as the 4GB and 6GB Hitachi models, the
5GB and 8GB Seagate models and the 2.2GB Magicstor drive are also
available but are often embedded in Pocket hard
drives, 'high end' mobile phones, music players, and other
entertainment devices. Such embedded devices are far more popular
than the loosely-sold Microdrives intended as a CompactFlash card
alternative.
In USA most
electronics shops do not sell separate Microdrives as they may find
it economically unviable to stock them due to the fast-moving
nature of the market, however they are readily available on several
websites. But in most developed Asian cities such as Hong Kong and Japan Tokyo, a 8GB version of the Seagate ST1 are
selling at the price (as of second quarter 2006) as low as USD $220
in retail shops, and under USD $50 on eBay.
Applications
- CF to IDE adaptors and USB card readers enable microdrives to
be used in computers, they can then be formatted with any
filesystem that the operating system supports such as ext3. It is even possible to run an
operating system directly from the Microdrive. Such a system would
be rather sluggish for today's standards but still a viable option
for some embedded applications. IDE adaptors are inexpensive
because, like the PCMCIA adaptors, they have no integrated
circuits.
- Some high capacity USB drives are microdrives with a USB
interface; they can often be recognized by a rectangular shape.
These devices are sometimes called Pocket hard
drives. However there is currently a trend for selling desktop
PCs with integrated multi-card readers. If this trend continues
this could eliminate the need to integrate them into pocket hard
drives with USB connections.
- The original JVC Everio
camcorders (GZ-MC200/MC100) used 4GB IBM/Hitachi Microdrives as
storage instead of the magnetic tape or DVD more commonly seen in
products of this type. Current Everio models use the more common
2.5" HDDs.
- Some PDA users use Microdrives to boost the storage capacity of
their PDA. The LifeDrive
has an integrated 4 gigabyte microdrive as its main selling
point.
- Microdrives are found in the discontinued iPod mini and Creative Zen Micro mp3
players, among others. Companies making such players order the
Microdrives in large quantities, which can mean that it is cheaper
to buy an mp3 player with an integrated Microdrive than a separate
Microdrive to add to an expandable mp3 player. An example is the
Creative MuVo; many of these were bought up by those interested in
purchasing a Microdrive and stripped for their Microdrive which was
then replaced by a lower capacity CompactFlash card.
- When combined with a PCMCIA adaptor and used in a laptop Microdrives can be a
viable alternative to USB flash drives purely due to their
price. The use of Microdrives over chip-based CF cards is unlikely
to make any notable difference to the battery life of the laptop,
and any impact that would damage the Microdrive is likely to break
other components of the laptop as well. However these devices
cannot be used with ordinary desktop PCs unless they are fitted
with PCI PCMCIA adaptors or CF card
readers.
- There are third-party devices intended to let users of the Sony PSP
use memory cards other than Memory Sticks. Some claim to be compatible
with MicroDrives, and some even come with a MicroDrive in the
package. However, while such converters work perfectly for other
kinds of flash memory (SD and CompactFlash), it is
no longer possible (due to firmware upgrades) to use actual
MicroDrives on the PSP. The acceptable timeout delay has been
decreased from the first firmware revisions, and as a result
loading a game from the hard disk results in a timeout error.
Sometimes when a device with an integrated Microdrive stops
working the device is taken apart and stripped of its Microdrive,
which is then sold on. Unfortunately, Microdrives taken from such
devices may not work in digital cameras. These drives must be
accessed using ATA
mode, which is not supported in all devices. Such drives,
therefore, do not sell for nearly as much as CF-enabled
Microdrives.
Devices with integrated
microdrives
Advantages of
Microdrives
- Until 2006, Microdrives had higher capacity than CompactFlash
cards.
- Microdrives allow more write cycles, making them suitable for
use as swapspace in embedded applications.
- Microdrives might be better at handling power loss in the
middle of writing. Flash storage always needs to move some old data
around while writing, to ensure the flash's finite write life is
consumed equally; if there were a bug in the wear levelling
algorithm it could cause data loss if the card were unplugged at
the exact wrong time. Data on a magnetic hard drive is modified in
place, and hard drive algorithms have many years more experience
and testing over Flash.
Disadvantages of
Microdrives
Inside a 1-inch Seagate drive
- As of 2006, Microdrive's capacity advantages were exceeded by
CompactFlash cards[4](which
are the same size and are often compatible with each other), and
USB flash drives.[5]
- Being mechanical devices they are more sensitive to physical
shock and temperature changes than flash memory, though in practice
they are very robust and manufacturers have added several features
to the more recent models to improve reliability.
- A microdrive will generally not survive a 4 foot (1.2 metres)
drop onto a hard surface where CF cards can be thrown off high-rise
buildings and still function.
- Newer Microdrives have a mechanism to hold the heads off the
platter while the device is not in use. Early IBM models do not
have this - when one gently shakes such a drive one can hear the
heads click from side to side.
- Microdrives are not as fast as the high-end CompactFlash cards;
they generally operate at around 4-6 megabytes per second while
high-end CF cards can operate at 45 megabytes per second. This may
cause problems for photographers who shoot sequences of large
images in rapid succession.
- They are not designed to operate at high altitudes (over 10,000
feet), but can be safely used on most commercial aircraft as cabins
are generally pressurized.
- Outside of the professional photography market, Microdrives
have more limited popularity by general consumers because many
newer compact cameras lack CF/CF II slots due to the increasing
popularity of portable flash media.
- Only high capacity models are manufactured, as it is not
profitable to make low-capacity Microdrives. At the end of 2005
only capacities above 2 gigabytes are manufactured while 256mb and
512mb CompactFlash cards were still in production. Lower capacities
are still readily available second hand on eBay but these are usually the same price as CF
cards of the same size.
- Unlike flash memory, Microdrives require power even when no
data is being transferred to them to keep the disc spinning. As a
result many devices such as the iPod mini leave the drive switched
off for most of the time while periodically starting it up to fetch
data from it to fill the device's buffer. Microdrives will switch
off after idling for more than a few seconds to counter this
problem however this means that more time is lost constantly
spinning the drive up. This effect would be particularly
problematic if an operating system is being run from the drive.
However the drive can be forced to stay running if the host device
is programmed to write random bits of data to it.
- Certain bus-powered CF card readers lack the power needed to
run a Microdrive although they do take CF II cards, when using such
a device it will usually be detected by the host but errors will
occur once the user attempts to access the drive.
- Some "OEM Only" drives use the CompactFlash form factor but
only provide a 5V IDE/ATA interface. These will not work in readers
or devices which expect a 3.3V interface and full CompactFlash
functionality [3],
- Microdrives also require some time to spin up, this is very low
when compared to regular hard drives but not as fast as flash
memory.
- Since Microdrives are often integrated in another device this
can cause trouble if the drive breaks, it is usually the most
fragile component of the device and if the device is out of
warranty it can be very difficult to replace the drive
CF hard drive models by
manufacturer
Many smaller sized models are no longer offered, as they
have been supplanted by flash memory.
IBM MicroDrive (now manufactured by
Hitachi)
- 170 megabyte
- 340 megabyte
- 512 megabyte
- 1 gigabyte
- 4 gigabyte
Hitachi MicroDrive
- 512 megabyte
- 1 gigabyte
- 2 gigabyte
- 3 gigabyte
- 4 gigabyte
- 6 gigabyte
- 8 gigabyte
IBM and Hitachi models fitted with 128 KB of cache memory
GS Magic
- 2.2 gigabyte ATA, USB(NATIVE), & CF variants
- 3 gigabyte ATA
- 4 gigabyte ATA & CF variants
- 6 gigabyte
Seagate ST1
- 2.5 gigabyte
- 4 gigabyte
- 5 gigabyte
- 6 gigabyte
- 8 gigabyte
These Seagate models are fitted with 2 MB of cache memory
Sony Compact Vault
- 2 gigabyte (rebadged Hitachi)
- 4 gigabyte (rebadged Hitachi)
- 5 gigabyte
- 8 gigabyte
Cornice
References
See also
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