JMicron

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JMicron Technology Corporation
智微科技
Type Public
Traded as GTSM: 4925
Industry Semiconductors
Founded September 2001
Headquarters Hsinchu, Taiwan
Key people MK Tsai (Chairman)
Tim Liu (CEO)
Products Integrated circuits
Website www.jmicron.com

JMicron Technology Corporation (Chinese: 智微科技; pinyin: Zhìwēi Kējì) is a Taiwanese technology corporation based out of Hsinchu. As a manufacturer of integrated circuits, they produce controller chips for solid state drives (SSDs), hard disk drives (HDDs), and peripheral devices.[1]

Its chips are used by a number of companies, such as ASUS,[2] Gigabyte, and MSI[3] in PC motherboards.

Products[edit]

SSD Controllers[edit]

JMicron currently offers a variety of options for flash controllers. On the client side, the 8 CE JMF667H and single CE JMF667 are the current 4-channel flagship models, offering up to a 512GB maximum volume each. The JMF667H has received generally positive reviews, being cited as both competitive and budget-worthy[4] when used with the correct type of NAND.[5] For instance, when paired with Toshiba's A19 NAND, the JMF667H has been shown to be capable of achieving the following metrics: 500 MB/s for 128 KB sequential read, 450 MB/s for 128 KB sequential write, and reaching 80,000 4 KB IOPS for both random read and write.[6] The JMF667H has also been found to have very low power consumption, with active idle power consumption in the 0.2-0.4 W range depending on the capacity of the controller, as well as an average power consumption rating of 0.36-0.78 W when examined in PCMark 7.[7] Certain drives driven by the JMF667H controller, such as the Kingfast C-Drive F8, have achieved high scores on independent review sites—for example, 90% on TweakTown.[8]

For industrial SSDs, JMicron offers the JMF606 and JMF607 as "economic" 4-channel and 2-channel models, respectively. Also in the -600 series are the JMF608 and JMF609 controllers, which are 4- and 2-channel models of the "cost-effective" variety (due to the lack of DRAM).

JMicron's SSD controller is widely adopted by many SSD manufacturers such ASUS Eee PC, Corsair,[9] OCZ, and Transcend. JMicron was the first[citation needed] company to provide an SSD controller chip to these companies, allowing them to produce reasonably priced MLC SSDs. JMicron was to announce a new SSD controller with a DRAM cache in Q3 2009.[10]

JMF602 would be succeeded by JMF612.[11]

Peripheral Device Controllers[edit]

  • PATA-SATA translation Bridge
  • USB-ATA bridge
  • 1394+USB-SATA bridge
  • PCI-Express-ATA bridge
  • PCI Express-1394 bridge
  • SATA Port Multiplier/Selector with RAID
  • PCI Express-Ethernet bridge
  • USB+SATA flash controller
  • PCI-Express flash card readers

Market Reception[edit]

When flash controllers were first offered to SSD manufacturers in 2008, JMicron's early JMF601 and JMF602 models were reported to have issues with write latency, causing a stuttering problem.[12][13] The performance problem was attributed to the small buffer size used in the controller.[14] Some manufacturers tried to get around the problem by using two JMicron controllers and added more cache, but this increased the cost and still failed to deliver the improved performance.[15] In June 2008, JMicron released version B of the affected controllers, which claimed to improve write latency and allow reserving more spare blocks to overcome the issue,[10] but Anandtech's test showed that although JMF602B has twice the cache of the JMF602A controller and has less stutter, 4KB random write has 74x the latency and under 2% write speed of Western Digital VelociRaptor 300GB.[16]

JMicron SATA/IDE controllers can be incompatible with some boot loaders. In particular, those using GRUB, such as Ubuntu, cannot boot in some conditions (2006/08, 2.6.17).[17] The 2.6.18 Linux kernel and JMicron controller BIOS 1.06.53[18][broken citation] solved these incompatibilities, but may not be present in existing products, or may require re-flashing the motherboard BIOS. Other bootloaders such as the Windows NTLDR boot loader and EXTLINUX work fine. It has been fixed by the latest distros.

According to the comprehensive analysis of Stuxnet virus released by Symantec in 2011,[19] a JMicron digital certificate for Windows got compromised, allowing attacker to digitally sign malicious drivers, then revoked by Verisign : "The attackers would have needed to obtain the digital certificates from someone who may have physically entered the premises of the two companies [Realtek and JMicron] and stole them, as the two companies are in close physical proximity." states the report.

See also[edit]

References[edit]

External links[edit]