JMicron
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| Industry | Computer |
|---|---|
| Headquarters | Hsinchu, Taiwan |
| Products | Chipsets |
| Website | www.jmicron.com |
JMicron Technology Corporation(Chinese: 智微科技) is a Taiwanese manufacturer of integrated circuits which mostly produces Serial ATA and related controller chips.[1]
Its chips are used by a number of companies, such as ASUS,[2] Gigabyte, and MSI[3] in PC motherboards, though because of difficulties, newer MSI models have moved to using integrated Marvell controllers.[4]
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SSD Controllers [edit]
JMicron's JMF601 and JMF602 SATA flash controllers were reported to have issues with write latency, causing a stuttering problem.[5][6] The performance problem was attributed to the small buffer size used in the controller.[7] Some manufacturers tried to get around the problem by using 2 JMicron controllers and added more cache, but this increased the cost and still failed to deliver the improved performance.[8] 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,[9] 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.[10]
JMicron's SSD controller is widely adopted by many SSD manufacturers such ASUS Eee PC, Corsair,[11] 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,[9] but no such announcement occurred.
JMF602 would be succeeded by JMF612.[12]
Linux Compatibility [edit]
JMicron SATA/IDE controllers are often incompatible with some boot loaders. In particular, those using GRUB, such as Ubuntu, cannot boot in some conditions (2006/08, 2.6.17).[13] The 2.6.18 Linux kernel and JMicron controller BIOS 1.06.53[14] 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.
Security breach [edit]
According to the comprehensive analysis of Stuxnet virus released by Symantec in 2011,[15] 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.
Products [edit]
JMicron makes products for a number of different applications, including:
- 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
- SSD controller
- PCI-Express flash card readers
References [edit]
- ^ JMicron's product list
- ^ Reference to JMicron on ASUS website.
- ^ MSI's original P965 Neo-F with JMicron controller
- ^ MSI P965 Neo-F version 2, with JMicron controller replaced
- ^ OCZ Once Again Slashes the Price of Core Series SSDs
- ^ G.Skill, Intel & Patriot SSD group test
- ^ Avoid SSDs with Jmicron's JMF602 Controller
- ^ Super Talent Claims Its SSDs Can Rock Intel's
- ^ a b Ng, Jansen (22 January 2009). "Exclusive Interview With JMicron on SSD Controllers". DailyTech. Retrieved 2009-01-23.
- ^ The SSD Anthology: Understanding SSDs and New Drives from OCZ
- ^ http://www.hardwaresecrets.com/news/4585
- ^ SSD Prices Could be Cut in Half Due to New JMicron Flash Controller & 32nm NAND Flash
- ^ Bug #57502: JMicron PATA/SATA Controller does not work
- ^ JMicron FAQ
- ^ W32.Stuxnet Dossier - Version 1.4 (February 2011)
External links [edit]
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