||This article possibly contains original research. (July 2011)|
Microdrive (MD) is a brand name for miniature, 1-inch hard disks designed to fit in CompactFlash (CF) Type II slots. The release of similar drives by other makers led to them often being referred to as 'microdrives'. As of 2011, Microdrives are viewed as obsolete, having been eclipsed by solid-state flash media in read/write performance, storage capacity, durability, physical size, and price.
The Microdrive was developed and launched in 1999 by IBM with a capacity of 170 MB. Capacity expanded to 8 GB by 2006. These units weighed about 16 g (~1/2 oz), with dimensions of 42.8 &mult; 36.4 &mult; 5 mm (1.7 &mult; 1.4 &mult; 0.2 inches) and were the smallest hard drives in the world at the time. The next year, 512 MB and 1 GB models became available. In December 2002 Hitachi bought IBM's disk drive business, including the Microdrive technology and brand. IBM Microdrives were then known as Hitachi Microdrives.
In 2004, Seagate launched 2.5 and 5 GB models, and referred to them as either 1-inch hard drives or CompactFlash hard drives due to the trademark issue. These drives were also commonly known as the Seagate ST1. In 2005 Seagate launched an 8 GB model. Seagate also sold a standalone consumer product based on these drives with a product known as the Pocket Hard Drive. These devices came in the shape of a hockey puck with an integrated USB 2.0 cable.
In 2004, a Chinese manufacturer called GS Magic started marketing small form factor HDDs for CompactFlash. They were sued by Hitachi for patent infringement of the IBM design (as opposed to Seagate, which used its own technology).
As of July 2012, no manufacturers seem to be making Microdrives.
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)|
- 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.
- As of 2006, Microdrive's capacity advantages were exceeded by CompactFlash cards (which are the same size and are often compatible with each other), and USB flash drives. As of 5 July 2012, 128 GB CF cards are available, offering more than 10 times the storage space of the largest Microdrive.
- 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 whereas CF cards can survive much higher falls.
- 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 GB are manufactured while 256 MB and 512 MB 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 ,
- 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.
MicroDrive models by manufacturer
- 170 MB
- 340 MB
- 512 MB
- 1 GB
- 4 GB
- 512 MB
- 1 GB
- 2 GB
- 3 GB
- 4 GB
- 6 GB
- 8 GB
IBM and Hitachi models were fitted with 128 KB of cache memory
- 2.5 GB
- 4 GB
- 5 GB
- 6 GB
- 8 GB
- 12 GB
Sony Compact Vault
- 2 GB (rebadged Hitachi)
- 4 GB (rebadged Hitachi)
- 5 GB
- 8 GB
- 2 GB
- 4 GB
- 4 GB
- http://findarticles.com/p/articles/mi_pwwi/is_200403/ai_mark767788306. Missing or empty
- By Howard French (5 March 2005). "The New York Times > Business > World Business > Whose Patent Is It, Anyway?". China: Nytimes.com. Retrieved 2012-11-03.
- SanDisk introduces the world’s highest capacity card for professional photographers - the 16-gigabyte SanDisk Extreme III CompactFlash
- Corsair launches 16GB Flash Voyager drive
- 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