The SD Association seems to be releasing new specifications faster than the industry and consumers can pick up. In June 2018, the SD 7.0 specification added SD Express cards with PCIe and NVMe interfaces for theoretical transfer rates up to 985 MB/s, followed by SD 7.1 specification in February 2019 adding SD Express to MicroSD card as well. The just-published SD 8.0 specification ups the ante further with SD Express now supporting dual-lane PCIe 4.0 with transfer rates up to 4GB/s. SD 8.0 is for full-sized SD Express cards that use the same NVMe upper-layer protocol, and remain backward compatible with earlier SD standards including UHS-III. The new higher bitrates will be used for data-intense wireless or wired communication, super-slow motion video, RAW continuous burst mode and 8K video capture and playback, 360-degree cameras/videos, gaming systems, multi-channel IoT devices, automotive devices etc… SD Express will be offered on SDHC, SDXC, and SDUC memory cards. SD 8.0 specification provides two transfer […]
Last Summer the SD association released SD 7.0 specification with two key new features: SD Express adding PCIe and NVMe interfaces to the legacy SD card interface for transfer rates of up to 985MB/s, and SDUC (SD Ultra Capacity) card allowing capacities of up to 128 TB. This all looks great, but while the latter was available for both micro SD cards and full size SD cards, microSD cards could not benefit from the new high speed interfaces part of SD Express specification. SD 7.1 specification fixes that, as the SD association has now added microSD Express card which will also be able to reach up to 985MB/s (in theory) thanks to PCIe/NVMe interfaces, so we’ll be able to get sort of “removable SSDs” for smartphone and other devices that compatible with SD Express. As illustrated above microSD Express cards will be available in various capacities as microSDHC Express, microSDXC Express and microSDUC Express cards. Beside the higher transfer rate, […]
Last year, the SD association introduced Class A2 application performance class for SD cards designed for optimal performance when running an OS or programs from the cards thanks to fast read and write random I/O, specifically 400O IOPS minimum for read operations, 2000 IOPS minimum for write operations. Since Class A2 was announced about 18 months ago, I simply assumed Class A2 SD cards were already available, but to my surprise I was wrong, as according to AnandTech, Sandisk Extreme micro SD cards are the first of the kind soon-to-be available commercially. Sandisk Extreme micro SD card specification: Capacity – 64GB, 128GB, 256GB, or 400GB Interface – UHS-I Sequential Speeds – Read: Up to 160 MB/s; Write: Up to 90MB/s (128GB to 400GB), up to 70MB/s (64GB) Random Speeds – Read: >= 4000 IOPS; Write: >=2000 IOPS SDA Labels – C10, U3, V30, A2 Temperature Range – -25 to 80°C Sandisk – part of Western Digital since 2016 – did […]
If you have to duplicate many SD cards for example to boot Raspbian on multiple Raspberry Pi board, one option is buy one of those SD card duplicators, but the problem is that they are not really cheap, for example the Systor 1-to-7 cards model sells for $540. Bob Brown, a retired senior lecturer, is now teaching K-12 students how to get started with Raspberry Pi boards, and must prepare bootable SD cards for his class. In order to save time, a duplicator would have been nice, but the price is too high, so instead he went with a DIY solution. You’ll first need some hardware, including a powered USB hub with the number of cards you want to duplicate, and corresponding SD card reader, and a larger micro SD card to hold Raspbian and/or other operating systems (optional, only for Raspberry Pi based duplicator). Mr. Brown made a 10-port SD card duplicator (1-to-9) for just under $100. One the […]
So this week-end, I started to play with ROC-RK3328-CC (Renegade) board that I received from T-Chip / Firefly-Team and as always, I used Etcher to flash the firmware images to micro SD cards. Once flashing is complete, you’ll get a screen mentioning Etcher Pro, a standalone hardware solution allowing to duplicate the content of one micro SD card to 16 other cards. That’s very interesting if you need to duplicate many cards for a project, but the only problem is that the device is not available just yet. So I thought such equipment must already exist and indeed, a company called SySTOR offers such systems able to duplicate one (micro) SD card to up to 199 other (micro) SD cards. Some of the specifications & key features of the system: Processor – Multi-core processor System Memory – 256 MB DDR3 Capacity – Various models from 4 to 200 micro SD card / SD card slots allowing the duplication of one […]
SD cards are known for the convenience, portability, and relatively cheap prices, but not so much for their performance which can be pretty poor especially for the cheaper and lower capacity models, and when fast random I/O is needed. The SD Association have been working on helping customer buy performant cards for their needs with – for instance – the app performance class introduced in SD 5.1 specification, which defines minimum random read and write speeds in Class A1 and Class A2 micro SD cards. However, the association has gone a step further with SD Express found in SD specification 7.0 that adds PCIe and NVMe interfaces to the legacy SD card interface. SD Express will enable theoretical data transfer rate up to 985 MB/s via PCIe 3.0, as well as advanced memory access mechanisms such as Bus Mastering, Multi Queue (without locking mechanism) and Host Memory Buffer thanks to support for NVMe 1.3 protocol. The SD 7.0 specification also […]
Linus Torvalds has just released Linux 4.16: So the take from final week of the 4.16 release looks a lot like rc7, in that about half of it is networking. If it wasn’t for that, it would all be very small and calm. We had a number of fixes and cleanups elsewhere, but none of it made me go “uhhuh, better let this soak for another week”. And davem didn’t think the networking was a reason to delay the release, so I’m not. End result: 4.16 is out, and the merge window for 4.17 is open and I’ll start doing pull requests tomorrow. Outside of networking, most of the last week was various arch fixlets (powerpc, arm, x86, arm64), some driver fixes (mainly scsi and rdma) and misc other noise (documentation, vm, perf). The appended shortlog gives an overview of the details (again, this is only the small stuff in the last week, if you want the full 4.16 changelog […]
Users of development boards booting from (micro) SD cards have often missed random I/O performance information to determine whether the device would performance well to run an operating system, but now that Google has implemented “adoptable storage” to let consumer run app from their micro SD cards, it has become an important differentiating factor for manufacturers, and the SD association announced A1 App performance class with minimum random I/O read/write performance and at least 10MB/s sequential write speed last year. The SD association has now unveiled Class A2 with better I/O performance with minimum requirements of 4000 IOPS for random reads, and 2000 IOPS for random writes, with the same 10 MB/s minimum sequential write speed. That means the application performance table now looks as shown below. Note that Class A2 is not available right now, and test requirements will be explained in SD 6.1 part 1 physical specification to be released later this year.Compliant (micro) SD cards will be […]
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