Secure Digital/mmc Slot
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History
- Secure Digital (SD) is a flash (non-volatile) memory card format and is used for storage. MMC and SD cards differ in their physical size, capacity and their usage. Both come in different memory sizes as well. While MMCs can be used in a standard SD card slot, the latter cannot be used in a MMC slot.
- Secure Digital Memory Cards Products including Top Brands like Stealth Cam, Spartan Camera, Lexar, Magellan and More! — 2 products / 4 models — Page 1 SD cards are based on the older Multi Media Card (MMC) format, but most (not all) are slightly thicker than MMC cards.
In 1997, Siemens AG and SanDisk developed the MMC card using Toshiba's NAND-based flash memory. As it uses NAND based flash memory, it is much smaller in size than the IntelNOR-based memory; such as CompactFlash. Originally it used a 1-bit serial interface, but with the new architecture, now it can transfer 4 or 8 bits at a time.
After the release of MMC cards most of the portable music players started using MMC cards as primary storage. But the music industry was skeptical about the use of MMC, as MMCs would allow easy piracy of music. So, Toshiba added encryption hardware in existing MMC and named it Secured Digital or SD card. This allowed Digital Rights Management(DRM) for the music. Matsushita, SanDisk, and Toshiba jointly developed, next generation secure memory card called the SD Memory Card. SD cards provide both an SDMI-compliant (Secure Digital Music Initiative) high-level of copyright protection and high-density memory capacity. Today, in many areas, MMC are being replaced by SD cards. The only reason why some devices continue using MMCs are because of their comparative lower cost than SD cards.
Size
The size of a standard MMC card is 24 mm x 32 mm x 1.4 mm while that of a SD card is 24 mm × 32 mm × 2.1 mm. So from the size comparison, we can see that SD cards are much thicker than the MMC cards, 2.1 mm against 1.4 mm.
Interoperability
Because of the size similarity, MMC cards can be also used in the standard SD card slot, but the reverse is not true.
Storage Capacity
MMCs are currently available in sizes up to 4 GB and 8 GB models. As of September 2007, SD cards were available in sizes from 8 MB to 16 GB. A few companies have announced SD cards with 32 GB also.
Usage
Amongst digital cameras, companies that use SD cards include Canon, Epson, Casio, HP while Epson and some models of Nikon and Sony cameras use a MMC card and compact flash memory depending on the model. In Mobile phones, Nokia uses both MMCs and SD cards which vary according to the model. Samsung and Motorola phones use SD cards. Amongst gaming consoles, Nintendo Wii and Sony Playstation 3 use SD cards while Xbox 360 uses a memory unit.
Different versions
Apart from the standard MMC there are other versions available also. They are Reduced-Size MultiMediaCard (RS-MMC), dual voltage MMC card (DV-MMC), MMC plus, MMC mobile, MMC micro and MMC secure.
RS-MMC has a size of 24 mm × 18 mm × 1.4 mm. It was released in 2004. RS-MMCs are smaller MMCs and use a mechanical adapter to elongate the card. It can be used in any MMC (or SD) slot and they are currently available in size up to 2 GB.
DV-MMC cards can operate at 1.8 V and the standard 3.3 V. Working at lower voltages reduces the card's power consumption, and thus used in mobile devices. In 2005, version 4.x of the MMC standard launched, to compete with SD card. This version is known as MMCplus (with the full size) and MMCmobile (with reduce size). These cards run at a higher clock speed (26MHz, 52MHz) than the original MMC (20MHz) or SD (25MHz, 50MHz) and it also has 4 or 8 bit wide data buses. Though these cards are fully compatible with MMC standard, but to use it, one needs to update the software.
MMC micro is a micro-size version of MMC and it has a dimension of 14 mm × 12 mm × 1.1 mm, it is smaller and thinner than RS-MMC. It also supports dual voltage, and backward compatible with MMC, and also can be used in full-size MMC and SD slots with a mechanical adapter.
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SD cards are normally available in two more versions. They are miniSD and microSD. MicroSD is the smallest memory card available commercially. The size is 15mm × 11mm × 0.7mm. It is about 25% of the size of an SD card. With the help of adapters it can be used in those devices which are meant for SD, miniSD, or Memory Stick Duo cards; but they are not universally compatible.
MiniSD card was launched in 2003 and has ultra-small form factor extension to the SD card standard. These cards were designed especially for mobile phones; and packaged with a miniSD adapter through which it can also be used in devices that equipped with a standard SD Memory Card slot.
SDHC (Secure Digital High Capacity, SD 2.0), an extension of SD card, allows larger capacity, more than 2 GB. It uses the FAT32 file system which supports partition sizes greater than 2 GB. SDHC card has 3 different classes depending on their speed. Class 2 has speed of 2 MB/s, class 4 has 4MB/s, and class 6 has 6 MB /s. SDIO is another standard for SD card, which stands for Secured Digital Input and Output.
Video explaining the various features of SD cards
References
The SD Card slot (Secure Digital) is found on select ThinkPads and Docking stations.
In addition to SD Cards, SD Card slots can also accept the older MMC (MultiMedia Card).
PCI-based SD Card slot
This implementation is called 'SD Card with IO support', and supports in addition to regular SD memory cards also special SDIO cards (e.g. Bluetooth, WiFi, etc).
Implemented by chips:
... and probably others
lspci reports it as a Ricoh device with PCI ID
- 1180:0822 (X Series, T61, Z60m, Z60t)
- 1180:0841 (Z Series)
- 1180:e822
- 1180:e823 (X220)
- 1180:e823 rev 4 (X230)
Linux support
You can read/write large SDHC cards since Linux kernel version 2.6.22, this has been tested on X41 Tablet, X41 and X40 with 16 GB SDHC (FAT32), 4 GB (non-HC, FAT32) and 2 GB (non-HC, FAT16) cards. However there have been some old reports that you can't, delete, create, resize or format partitions, there seems to be no problems with this on 2.6.24. These problem will not exist if you use an USB connected SDHC card reader instead of the internal one, so you can always use the cards.
The driver was coded by the SDHCi project supporting these and other SD controller chips, making them work with SDHC cards as well. The driver (modules sdhci and sdhci_pci) has been reported to work on ThinkPad X40, X41, Z60m, Z60t, X60 and X61 models, and has been available in mainline kernel since 2.6.17-rc1. See also 'How to get the internal SD card working'.
Problems with Standby / Hibernate
Add the follwing line to the # /etc/pm/config.d/00sleep_module to unload the module before standby:
'Got data interrupt' error messages
If you see error messages like
after inserting an SD card, try re-loading the sdhci module with a parameter debug_quirks=0x40. Solved the problem on a T61.
Windows support
The Microsoft hotfix 934428 is available here [1] it adds SDHC (SD High Capacity) support to Windows XP SP2 systems.
02-01-2009 NOTE for SDHC cards using Windows 2003 Server and Vista. IBM/Lenovo nor Microsoft supports this KB934428 with 2003 Server and the update.exe halts with OS version mis-match error when executed on 2003 or Vista despite the fact the sff*.sys driver files are perfectly compatible. Manual extraction and installation of the driver file still fails to properly mount and read 4GB+ SD cards despite indicators and messages of successful installation.Solution requires obtaining sdhcinst.dll from 2003 install media or copying from the %systemroot%system32 directory into the %systemroot%system32drivers directory before manually installing driver files and pointing to the ..SP2QFEicsdbus.inf file. A copy of sdhcinst.dll copied from a KB934428 patched XP workstaiton is identical to all 2003 Server versions and Vista since Microsoft clings to a universal drivers model. The KB934428 doesn't include the sdhcinst.dll file.Follow this link to lenovo forums for longer but just as simple explanation.
[2][OT] This solution has also been successfully tested on systems from different manufacturers and with non Richo card readers.
14-04-2010 NOTEThinkpad Z61p SD-reader can accept SDHC cards up to 32GB in Windows (XP,Vista,7)
with updated Texas Instruments Media Card Reader Driver [3] and by modifying registry:
HKEY_LOCAL_MACHINESYSTEMControlSet001Servicestifm21Parameters
Original Key Value: SDParam = 17 (Decimal)
New Key Value: SDParam = 16
After the hack, reboot the computer. Some users have also reported SDParam = 1 to work.
Models featuring this Technology
- ThinkPad T410, T410i, T430, T510, T510i
- ThinkPad W500, T61, T61p
- ThinkPad X40, X41, X41 Tablet
- ThinkPad X60, X60s, X60 Tablet, X61, X61s, X61 Tablet, X201, X201i, X220
- ThinkPad Z60m, Z60t, Z61p
USB-based SD Card slot
This implementation only supports SD Memory cards.
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Linux support
Should be supported by the Linux USB Storage drivers (usb-storage).
Models featuring this technology
Secure Digital/mmc Slot Machine
- ThinkPad X200