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The Microdrive is a brand name for a miniature, 1-inch hard disk designed to fit in a Compact Flash (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^{[citation needed]} 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.

These drives fit into any CompactFlash II slot; however, they may consume more power than flash memory (on the order of 190mA, peak 310mA, at 3.3V) 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 4 GB or more, but must be formatted for a file system which supports this capacity, such as FAT 32 or NTFS, which may not be supported by older CompactFlash hosts, but it is possible to partition a drive so it will contain a partition less than 4GB.

Contents 1 History 1.1 Microdrive models by timeline 2 Availability 3 Applications 3.1 Devices with integrated microdrives 4 Advantages of Microdrives 5 Disadvantages of Microdrives 5.1 CF hard drive models by manufacturer 6 References 7 See also 8 External links

This section may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can (August 2007).

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.

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^{[citation needed]} (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.

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	8 gigabytes (Hitachi), 8 gigabytes (Seagate)
2006	8 gigabytes (Hitachi), 8 gigabytes (Seagate)
2007	Hitachi has promised a 20-gigabyte microdrive to be released in 2007[1]

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 inviable 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 USD220 in retail shops, and under USD100 on eBay

• 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 FAT or 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 as they have no integrated circuits like the PCMCIA adaptors.
• Some high capacity USB drives are comprised of 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 PC's with integrated multi-card readers. If this trend continues this could eliminate the need to integrate them into pocket hard drives with USB connections.
• Microdrives are popular with professional photographers, who take advantage of their multi-gigabyte capacity to be able to store high-resolution, print-quality photographs without too much concern about storage space. Outside of the professional and prosumer photography market, Microdrives have more limited popularity because many compact cameras that had CF slots did not have type II slots (or support the power requirement).
• The original JVC Everio camcorders (GZ-MC200/MC100) utilised 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 a 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 PC's unless they are fitted with PCI PCMCIA adaptors or CF card readers.

• Many embedded industrial applications and University data-collecting projects

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.

• Apple iPod mini - 4GB and 6GB Hitachi (CF mode disabled)
• Creative MuVo - 4GB Hitachi (CF mode disabled in later models)
• Creative ZEN Micro - 5GB/6GB Seagate
• Creative ZEN MicroPhoto-8GB Seagate
• Dell Digital Jukebox 5GB Seagate ST1
• Hewlett-Packard Photosmart 475 - Unknown (1.5GB available to user)
• HTC Athena (Dopod U1000, HTC Advantage, T-Mobile Ameo) - 8GB Unknown (most suggest Hitachi)
• iriver H10 - 5GB and 6GB Seagate
• Nokia N91 - 4Gb Hitachi
• palmOne LifeDrive - 4GB Hitachi
• Rio Carbon - Seagate ST1 5GB
• Sharp Zaurus Sl-C3000
• Sharp Zaurus Sl-C3100
• Sharp Zaurus Sl-C3200
• Sony NW-A1000 - 6GB Hitachi
• TrekStor vibez - 8GB/12GB Cornice Dragon
• Olympus M:robe m100 mp3 player

• Microdrives have long reigned supreme in capacity. Flash drives have recently overtaken microdrives here, but all is not lost. Advances in magnetic hard drives are still coming, squeezing those into a next generation Microdrive could still win back the capacity "crown".
• Microdrives allow more write cycles, an advantage for embedded operating system applications.^{[citation needed]}
• 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. A bug in that data-moving algorithm could cause data loss if the card is unplugged at the exact wrong time. Data on a magnetic hard drive generally stays put, and hard drive algorithms have many years more experience and testing over Flash.

• 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. Using a soft packaging (e.g. Polystyrene foam) can allow survival from a longer drop.
• 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 20 megabytes per second. This may cause problems for photographers who shoot sequences of large images in rapid succession.
• Not designed to operate at high altitudes (over 10000 feet), but can be safely used on most commercial aircraft as cabins are generally pressurized.
• 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.
• 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

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

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

• 4 gigabyte

• PC Card - CompactFlash - Microdrive - MultiMediaCard - Secure Digital Card - Memory Stick - xD-Picture Card - SmartMedia
• Digital cameras
• Digital camera memory media

• Review: IBM's 1GB Microdrive - Review on MP3 Newswire
• Hitachi Global Storage Technologies (HGST)
• Review of Seagate ST1 5 GB 1-inch hard disk for CF
• Taking apart a 5GB Seagate Microdrive

v • d • e Memory cards
CompactFlash (CF) • JEIDA • Memory Stick (MS/MS-PRO) • miCard • Microdrive (MD) • MultiMediaCard (MMC) • PC Card • Secure Digital (SD) • SmartMedia (SM) • SxS • Universal Flash Storage (UFS) • USB • xD-Picture
Comparison of memory cards • SD Card/MultiMediaCard Family Comparison