OS/2, eCS & ArcaOS - Technical > Storage


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--- Quote from: Per E. Johannessen on December 11, 2020, 06:03:18 pm ---What external disk brand/model do you have?

--- End quote ---
It does not seem to me that it is a problem of the disc, if not of the feeding. As Ivan told you. I use an e-sata cable with a usb booster just to have more amps as booster. The disk is a small one from a normal 2 1/2" laptop not ssd. It is not a large disk 3 1/2" that possibly needs more power and this cable that I am telling you is insufficient.

Hi Per

I have an Icy Box external disk enclosure, model IB-351StU3S-B, which has both USB3 and eSATA connection options - see https://www.watercoolinguk.co.uk/p/Icy-Box-IB-351StU3-B-35-inch-HDD-Enclosure-USB-30-Black_48539.html

It is for 3.5" disks but should be possible to find or make some sort of 3.5" to 2.5" adaptor.

As others have pointed out eSATA disks need to be already attached at boot time so the disk is treated as a standard SATA drive - hot plug and eject are missing from our OS. Now that we have USB3 that is the preferred connection option here for convenience.



Per E. Johannessen:
Thanks to all for info.

Doug, I had hardware controlled RAID in mind when mentioning an enclosure for 2 disks.
Not really necessary, just that I'd like to try it.

Pete, I was actually looking at various Icy Box disk enclosures but couldn't find any wth eSATA.

Anyway, both of you mentioned USB 3 so I think I'll go for that.

Andi B.:
I've an internal Fantec enclosure where I can insert 3.5" and 2.5" SATA disks. Maybe you can find an external one. Mine works very well with 3,5" disks but has some compatibility problems with different 2.5" SSDs. Not what you're looking for but USB3 is terrible slow compared to that. About 5-10 times slower. Regarding the discussion at the testers group about USB transfer speed it seems we can never get more than about 20MB/s. Although I can't believe it this is what David has to say about that. While with other OSes write/read speed to USB3 attached disks is only limited by the disk speed, for us it stays at about 18MB/s (same as with USB2 and even slower as with old USB2 drivers a few years ago). Of course all measurements made with the same system and same disk and same connector/cable.....

Doug Bissett:

--- Quote ---Regarding the discussion at the testers group about USB transfer speed it seems we can never get more than about 20MB/s
--- End quote ---

I have seen a little faster than 20 MB/s, with the AN USB X driver. It all depends on whether the connectors work properly ( (A type, especially, are very marginal), which USB 3 adapter I use, and which device. Most devices just won't go as fast as USB 3 is supposed to go (you are lucky if they do 20% of what they should do). That usually has nothing to do with the driver, most of the time, it is the device (some controllers aren't worth even trying too). You also need to remember, that USB write, is always slower than USB read (usually half). There is also a feature (called "USB BOOST", on my machine), that helps USB speed, when the OS knows about it. I think that needs some sort of support from the OS. It also needs to be enabled in the BIOS.

FWIW, I don't get more than 20 GB/s using e-Sata either. It can be affected by how fast the (e-)Sata controller is designed to run. It also depends on how you measure the speed. There are many things that can affect it (including the cable length). On disk cache seems to be important.

--- Quote ---About 5-10 times slower.
--- End quote ---

This is almost guaranteed to be a bad USB connector. 5 -10 times slower indicates that you are connecting to the HS controller, not the SS controller. There is a tool, supplied to the Arca Noae testers, that tells you exactly how a device is connected. It seems to be essential to be able to adjust the connectors so they actually work. Unfortunately, there are no plans (that I know of) to release that tool to the users (they probably don't want to support it). There is a tool, by the same name, that does something similar in windows. It is called USBTREE, if anybody wants to give it a shot. I have no idea if it is actually the same program, and I haven't tried it myself. YMMV.


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