USB Write Speeds

[mondo1976]

I've had some issues with write corruption apparently tied into the write speed of the USB stick (in conjunction with an HxC Gotek, in this case).

I get passable performance out of a Sandisk Ultra Fit 8GB, but a newer Sandisk Ultra Fit 16GB USB 3.0 can't seem to keep up with the smaller writes and ends up trashing the HFE.

Does anyone know of any "nano" sized USB drives that have a faster/comparable small write speed than the Leef Supra? Also, does anyone have any real world experience with the Leef Surge 8GB, especially with time sensitive applications like formatting?

[Jeff]

Someone else seems to have find some good usb stick :

... A lilttle research disclosed the fact that the SanDisk Extreme USB 3.0 sticks have about 10x better small R/W performance than any of the competition. I bought one of these and discovered that a lot of problems went away. The Gotek + USB now worked in all cases where I previously had to use a USB hard drive. One problem down.
...

[snhirsch]

Yes, the Sandisk Extreme has by far the best small R/W performance of any USB thumb drive.

[mondo1976]

Okay, but isn't the Sandisk Extreme only available in the larger form-factor? I've never seen any available in the "Fit" size or anything comparable.

[Jeff]

Okay, but isn't the Sandisk Extreme only available in the larger form-factor? I've never seen any available in the "Fit" size or anything comparable.

Ok i understand your issue. These small usb stick are particulary bad regarding the write performance.

BTW what is your system ?

[cedric731]

Is it possible to use an adaptor to bypass the usb write speed issue?
For example:
- USB to CF
- USB to SD
- USB to MicroSD

Maybe the write speed can be better or more stable?

[mondo1976]

Okay, but isn't the Sandisk Extreme only available in the larger form-factor? I've never seen any available in the "Fit" size or anything comparable.

Ok i understand your issue. These small usb stick are particularly bad regarding the write performance.

BTW what is your system ?

I've tried different small sticks on a Yamaha TX16W. Formatting doesn't work, unsurprisingly, but I can get other writes to work using an Ultra Fit 8GB; larger capacities are apparently too slow.

I'm also working with an Emu Emax. I've tried the Leef Supra 16GB which is supposed to be blazing fast at small block writes, but it's still not reliable enough with the Emax. Formats don't work (no surprise), and copying entire disks only works rarely. Copying an OS from disk to disk works about 50% of the time. Basically anything moving a lot of data (if 800k can be considered a lot, ha) has a strong chance of taking too long at a random point in the write. Sometimes retrying the write works, sometimes not.

Tech info: I'm aware that reformatting a USB stick can change how the FAT32 sectors align with the block sizes of the USB stick. The Leef Supra is stock-formatted at FAT32 and I have not altered it at all, so it should be as fast as it'll ever get.

[Jeff]

Well unfortunately i am not surprised by the results. This hardware is too cheap to be reliable at writing : It miss some embedded RAM able to store the whole disk image to avoid the USB stack and flash write latencies.
But this design is cheap and this is what matter for most of people unfortunately...

The Emax is an hard case : It doesn't like the write latencies at all.

Anyway i will add the write support to the raw (img) images. The results may be better.

So stay tuned !

[mondo1976]

The Emax is an hard case : It doesn't like the write latencies at all.

Anyway i will add the write support to the raw (img) images. The results may be better.

So stay tuned !

If you have time, could you elaborate on what you mean by write support to the raw images and why that would potentially improve the write issue? Simple curiosity.

At any rate, you've done an amazing job with the Gotek and I can always go for the larger format Extreme, so one can't complain too much

But any improvements would be very welcome!!

Additional USB stick performance info: Sandisk Cruzer Glide 16GB & Ultra Fit 16GB are inadequate for EMAX/TX16W. Leef Supra 16GB & Sandisk Ultra Fit 8GB are hit-and-miss with the EMAX and seem to work fine with the TX16W.

I'll post here if I stumble upon any sticks that work reliably with the EMAX (either standard or nano).

[snhirsch]

Well unfortunately i am not surprised by the results. This hardware is too cheap to be reliable at writing : It miss some embedded RAM able to store the whole disk image to avoid the USB stack and flash write latencies.
But this design is cheap and this is what matter for most of people unfortunately...

I think the Gotek serves an important niche. You've done a great job of making a sow's ear into a silk purse . I ended up ordering a "real" HxC from Lotharek and will use that for critical applications. In read-mostly applications the Gotek will continue to be useful and I encourage you to continue development.

[Jeff]

If you have time, could you elaborate on what you mean by write support to the raw images and why that would potentially improve the write issue? Simple curiosity.

The HFE file store all magnetic data : gaps, sectors headers , CRC... In fact this is a direct copy of the magnetic support. That's why the HFE is more than twice time bigger than an simple data sector dump file (img/dsk). This allows to support any kind of disk format without any change into the software.
The counter part is the higher bandwidth required to read/write these images.

With a simple data sector dump, you have just to push/pop the sector data to/from the usb disk. But you have to add a real time iso/mfm sector encoder/decoder into the firmware plus find a way to specify the disk geometry if you want the emulator to be versatile. The realtime encoder is already into the firmware. I need to finish the write part.