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  1. #1
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    Question Extremely Slow Disk Access in Emulator

    Hi,

    WARNING: I'm new to Symbian.

    The code I'm porting reads a number of data files before starting up. For testing purposes I put the files on c:\ (which maps to C:\Symbian\9.1\S60_3rd_MR\Epoc32\winscw\c)

    On a WinCE device the loading of the data takes about 1/3 of a second and on the WinCE emulator more or less the same.

    When I launch the application in the EPOC32 emulator (S60 SDK MR) it takes ~ 10 minutes to read the files. When a step through the code every single I/O operation (fseek, fread) seems to take > 1 sec (BTW, I'm using the OpenC lib)

    I found some flags in EPOC.ini to control the data transfer rate: DiskRead & DiskWrite. I set both of them to zero (and one) but made no difference.

    Is that a common problem?
    Do I have to use the native file objects instead of OpenC -or- is this an emulator issue?

    Thank you,
    Nikos.

  2. #2
    Nokia Developer Moderator
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    Re: Extremely Slow Disk Access in Emulator

    First time I hear this complaint about the emulator. How many files are you reading and how big are they? What kind of speed do you get on a real S60 device?

  3. #3
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    Re: Extremely Slow Disk Access in Emulator

    There are three data files:

    Data1.dat is 177 KB
    Data2.dat is 51 KB
    Data3.dat is 293 KB.

    I ran FileMon to see what EPOC.exe does when it reads the data files and in between file accesses it loads
    Code:
    \release\WINSCW\UDEB\regtest.exe
    (no idea what that does).

    Note that it loads that file for each single I/O access (!)

    I have the FileMon trace if it is of any use.

    EDIT: I cannot run the game on a device yet - I'm testing stuff as I port them on the emulator.

    Thank you,
    Nikos.

  4. #4
    Nokia Developer Moderator
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    Re: Extremely Slow Disk Access in Emulator

    It is clear now, it is the Open C Plugin. Until this is fixed I would suggest that you read the entire file in one big buffer and then process the data from memory.

    On device you will not have this problem.

  5. #5
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    Re: Extremely Slow Disk Access in Emulator

    That's not really an option - is there anything else I can do to fix this?

    If not I'll use the native classes for I/O.

    It's just impossible to debug the game as is.

    Thank you,
    Nikos.

  6. #6
    Nokia Developer Moderator
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    Re: Extremely Slow Disk Access in Emulator

    Well, despite my confident answer above I am not 100% sure that the problem is caused by Open C through that regtest.exe. I'm forwarding this to the R&D guys for investigation and once the problem fixed we will surely let you know about the solution.

  7. #7
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    Re: Extremely Slow Disk Access in Emulator

    Thank you,

    Just to let you know that using RFile works fine.

    Cheers,
    Nikos.

  8. #8
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    Smile Re: Extremely Slow Disk Access in Emulator

    I am not sure that this will works for you ,but when u run your program in Carbide , you just remove path from run bracket and make it blank .so emulator will start in minimul time. Try it

    Cheers

  9. #9
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    Thumbs down Same problem here

    File access (fopen, fread) using OpenC on emulator just take for ever and end up freezing the emulator. We are talking about files no bigger than 400KB and even on smaller once <50KB it's exactly the same behaviour. I observed that same problem on two different development PCs.

    It just makes the OpenC SDK useless if file I/Os are not working on the emulator. I have a hundred other things to debug and fix before I can try running my code on a device so the fact that it works fine on the target is not very helpful for me.

    BTW I was initially trying to use functions from Symbian stdlib implementation as far as I can remember they use to work fine on earlier SDKs but now fopen keeps returning NULL. So I thought it was time for me to use OpenC and ended up with that problem.

    I guess I'll have to use that good old RFile for now.

    There is something else I don't get:
    It looks like I'm not getting any linker error if I don't include libc.lib in my MMP. Is Carbide somehow working around that missing library?
    Last edited by lenclud; 2007-07-05 at 01:58.

  10. #10
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    Re: Same problem here

    Even reading a big chunk in one single fread as opposed to have a lot of fread in a loop takes a looooong time :)

  11. #11
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    Re: Same problem here

    I am facing same issue, has any one found any workaround as yet.
    Also, Since I am using a third party library on symbian emulator(Written in openc) to create a new application I really can't change the code either.
    It is really frustrating when emulator is too slow or keeps on hanging

  12. #12
    Nokia Developer Moderator
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    Re: Extremely Slow Disk Access in Emulator

    The maintenance release version of the Open C plug-in was supposed to solve this problem. Are you using it? Or are you using the 3.2 SDK with integrated Open C support?
    -- Lucian

    If you are not yet a DVLUP member it is time to correct that mistake :) Click here to join: http://www.dvlup.com/lucian/Invite

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