Please increase FAT32 read and write speed

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Mrodfr
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Re: Please increase FAT32 read and write speed

Post by Mrodfr »

hello,

My 2,1 mo/s write or read speed with crossDOS /FAT32 on Update3 is with my HD and my 16go USB stick (with the low cluster AOS4 support).

This same key write around 8mo/s on a PC and read around 16mo/s on a PC (with the PC HD to the USB stick).

I know that read and write speed with AOS4 filesystem are much more superior, I think there are something around crossDOS that limit the speed.

kas1e
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Re: Please increase FAT32 read and write speed

Post by kas1e »

@nexus
I think, you still misunderstood ssolie.

You benchmark is reading from RAM: or writing to RAM:
Both involve RAM:
Yes. The same test happens for 2 usb2 stacks on pegasos2. One on os4u3 with Sirion, and one on mos2.7 with Posedeon.
Since it is currently slower than needed to access RAM: your benchmark is obviously slower on OS4 as it could be.
Did i understnad right, that aos4 realisation of RAM: are slow than it should be ? I.e. only aos4 realisation of RAM: are slower ?
If this is the reason for you 300% difference, I don't know or if in addition Sirion or CrossdosFilsystem causes
additional slowdowns, I don't know either. However, since your tests involves RAM: you cannot easily
claim that (if *I* understood ssolie correctly).
For me, RAM:, its something which we can't claim in that tests. Why ? Because writing from RAM: to SFS stick are more or less fast. But writing from RAM: to FAT32 stick, are very slow. And i show on benchmarks, that is radically slow. I.e. you can just cut off all the Posedeon/Mos speed from those benchmarks, you will see, that RAM: works more or less fine and with writing to, and with writing from, but, in case of only one single benmark : writing from RAM: to CRossDoss , you have reall slowdowns, which, should't happens. Not because of RAM (because it works fast when you do the same , but just on SFS stick).

That is cleary problem of CrossDoss.

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ssolie
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Re: Please increase FAT32 read and write speed

Post by ssolie »

kas1e wrote:Did i understnad right, that aos4 realisation of RAM: are slow than it should be ? I.e. only aos4 realisation of RAM: are slower ?
Again, the implementation of RAM: (ram-handler) is known to be slow. It is a known problem. It is not a high priority right now.
kas1e wrote:That is cleary problem of CrossDoss.
This is a problem with ram-handler (again, a known problem), possibly CrossDOS (due to missing large cluster support) and likely the USB stack (slower transfers).

I appreciate that you are trying to help but you only have a limited view of things and no access to the actual source code.
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kas1e
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Re: Please increase FAT32 read and write speed

Post by kas1e »

@ssolie
This is a problem with ram-handler (again, a known problem),
But you agree, that if writing from RAM: to SFS stick give us already say 5mb/s , then, writing from RAM: to FAT32: stick also can have 5mb/s (via the same ram-handler, just beause its already give 5mb/s from RAM: to SFS). Or you saying that problems with RAM: happens only with FAT32 ?

For now, if i understand your replies correctly, all of this mean:

-- speed of whole sirion-usb2 slower in compare with posedion (when RAM: is included in tests) , just because there is slow realisation of RAM: on os4
-- the much slower results with writing from RAM: to FAT32 are happens due to missing large cluster support in cross-dos

Right ?

Maybe i really can't understand what you trying to say, but imho if writing from RAM: to SFS give 5mb/s , then writing from RAM: to FAT32 also can give us 5mb/s, right ? (with the same ram-handler, of course).

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Re: Please increase FAT32 read and write speed

Post by tonyw »

It's not that simple. The way that CrossDOS reads the RAM: contents may influence the RAM: speed. CrossDOS is itself a filesystem, and one filesystem reading another filesystem through DOS (which is translating from one API to another) can introduce many strange side effects.

The answer is that we can't say that there is a single cause, and there are several components affecting one another, with unknown results.
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salass00
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Re: Please increase FAT32 read and write speed

Post by salass00 »

tonyw wrote:It's not that simple. The way that CrossDOS reads the RAM: contents may influence the RAM: speed. CrossDOS is itself a filesystem, and one filesystem reading another filesystem through DOS (which is translating from one API to another) can introduce many strange side effects.
What are you talking about?? CrossDOS doesn't read anything from RAM:, it is the c:copy command (or whatever other program was used for copying files) that reads from RAM: and then writes to CrossDOS filesystem.

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Re: Please increase FAT32 read and write speed

Post by kas1e »

@tonyw
The way that CrossDOS reads the RAM: contents may influence the RAM: speed.
Then crossdos do wrong way , and should be rewrited to right way. And even with slow RAM: realisation, it should be just like copy from ram: to sfs (and posedeon tests, shows us that is it, even with crossdos its a bit faster that with sfs !).
CrossDOS is itself a filesystem, and one filesystem reading another filesystem through DOS (which is translating from one API to another) can introduce many strange side effects.
? Even if not take into accaunt what Salas00 says, then its all still about cross-dos only. I mean even with slow realisation of RAM: speed of writing from RAM: to SFS or to CrossDos should be _the same_.

Even if it heavy use RAM: (which are slow, ok) something still _very_ different in compare with sfs, but should be the same. For example , sirion give us 5mb/s for writing from RAM: to SFS, but from RAM: to FAT32 : 2.6mb/s ! While _should_ be the same 5mb/s. I not saying now about comparing with posedeon, where its all give 7mb/s. Ok, our ram: are slow, so it give 5mb/s, but that should be the same and for SFS and for FAT32 , even, with current-slow realisation of ram:

The only reassons for which we can blame now RAM:, its a differences with posedeont : 5mb/s vs 7mb/s. But differences beetwen sfs and fat32 should not be present (and even more, fat32 should be a bit faster), even, with current-slow realisation of RAM:

Make firstly cross-dos working the same fast as with sfs (5mb/s), and then anyone can start to blame RAM: because of differences with posedeon (5mb/s vs 7mb/s).

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ChrisH
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Re: Please increase FAT32 read and write speed

Post by ChrisH »

I have to say I agree with Kas1e here. If RAM->SFS speed is fast & RAM->CrossDos is slow, then CrossDos is at fault, not RAM & not USB.

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Re: Update4: Please increase FAT32 read and write speed

Post by samo79 »

kas1e wrote:from RAM: to FAT32 (Sirion 2.6Mb/s, Poseidon 7.7Mb/s)
from FAT32 to RAM: (Sirion 9.7Mb/s, Poseidon 15.5Mb/s)
from RAM: to SFS (Sirion 5.1Mb/s, Poseidon 7.2Mb/s)
from SFS to RAM: (Sirion 10.1Mb/s, Poseidon 16.4Mb/s)
Well according to the same user the result now is a bit better (with Update 4) than before with the update 3 altrough the transfer from RAM to FAT32 still a bit slower altrough certain tiny improvement is visible here aswell
from RAM: to FAT32 (Sirion 2.8Mb/s, Poseidon 7.7Mb/s)
from FAT32 to RAM: (Sirion 10.4Mb/s, Poseidon 15.5Mb/s)
from RAM: to SFS (Sirion 5.5Mb/s, Poseidon 7.2Mb/s)
from SFS to RAM: (Sirion 10.4Mb/s, Poseidon 16.4Mb/s)

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