 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Microcontroller and PC projects : Lovely USB flash-drive....
| Author | Message | ||||
Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9306 |
Stay away from the Netac 8GB USB2 flash-drives, if you want to save your sanity!   MOST flash-drives in the USB2 flavour, can manage at least 20-25MB/s sequential read rate, and usually between 5-10MB/s sequential write rate. I thought these were kinda slow, so I tested them, and for brand-new flash-drives.....wow!  2MB/s write rate I think is a new low. I have tested heaps of flash-drives, and even the ones they give away as a promo can usually acheive the more standard 20MB read and 5-10MB write, but not these! I know, I know - Netac is a low-budget brand, so what can you expect, but these were interesting results!  I bought four of them, and ALL of them are the same when tested, so it was not just one dud one that I might have got. Keep your distance from those drives! In fact, when I setup one of these with a copy of Linux Mint on one, and Windows 10 on the other, BOTH of them generated read-errors during the setup process - as if the drive just basically gave up and stopped reading past a certain point. I could send a report back to who I got them from(NOT ebay or AE, I got them from a NZ shop), but for the price of them, I don't think it is worth kicking up any kind of fuss. Interestingly, I have used Netac SSD's before, and they seem to run beautifully. Fast and never any problems, so I guess.....the luck of the draw perhaps? Smoke makes things work. When the smoke gets out, it stops! |
||||
| EDNEDN Senior Member  Joined: 18/02/2023 Location: United StatesPosts: 118 |
I run https://h2testw.org/ on any SD Card or Thumb Drive I buy. More than half of the stuff on eBay is fake. And https://h2testw.org/ will tell you what you got. It might be worth while to do a quick test and run https://h2testw.org/ to see if the devices are 'real'. You shouldn't be getting read errors when they are almost new. But that is what happens when you start putting data on the fake devices. |
||||
phil99 Guru  Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
Part of the issue with cheap flash drives is that they store the data as an analogue voltage so a number of bits can be crammed into a single cell. A marginal chip may have leaky cell capacitors causing the value to drift. Refresh cycles are supposed to correct this but if there is too much leakage between cycles the data is corrupted. With no power the leakage is much less but risky for long term storage. |
||||
| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3801 |
For Linux use f3 (Fight Flash Fraud) John |
||||
Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6787 |
According to an item on The Register the general standard of USB flash drives is falling. Part of the problem is in stuffing more bits per cell in, but it also looks as if many cheap (and some not so cheap) drives are using part-functional reject chips. These often have the markings sanded off. The major problem here is that there are few, if any, spare cells available so the lifetime is very poor, even if the capacity is correct at the beginning. Unfortunately you appear to get what you pay for nowadays. If something looks cheap then it is quite likely to be rubbish. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
||||
 Print this page |
