On 03/01/2018 09:20 PM, Timothy Pearson wrote:
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On 03/01/2018 01:36 PM, Daniel Kulesz via coreboot wrote:
Hi,
(3) put in some PCIe SATA3 card => any recommended chips that respect freedom?
There are very few. You can try some of the Marvell devices but you will still be limited by the host side bus as these old Opterons only support PCIe v2.
Marvell and Asmedia controllers on sata cards are kinda garbage, many quirks.
Neither respects freedom anyway but a SAS controller crossflashed to IT (dumb) mode (so that it does not have any RAID capability) is the most reliable way to add Sata ports to a board, as SAS is retrocompatible with Sata, and SAS controllers have an entirely different level of quality (both hardware and drivers).
(4) get a m.2 SSD instead together with some PCIe adapter => the cards don't have a co-processor, right?
Yes, they do. NVMe devices have an integrated proprietary controller to manage data storage / wear levelling.
If we go that way, also mechanical hard drives, USB flash drives and pretty much any storage device showing up as "block device" has a storage controller running a proprietary firmware.
SSD firmware is more complex and their controllers are very beefy and usually multicore because of performance though.
(5) stay with SATA2 and live with the limited speed
Any recommendations for a freedom-respecting choice?
Sata2 speed limitation is less bad than it might sound. What matters most for system responsiveness is the transfer speed on random read/writes, which is NOT anywhere near Sata 2 speed cap, more like 20-50MB/s at most on very fast SSDs. Just look up SSD benchmarks for actual stats.
The high speed numbers on SSDs are for sequential transfers, for example when you copy over a relatively large file, and that will hit the Sata 2 speed limitation.
-Alberto