×

Discussion Board

Results 1 to 7 of 7
  1. #1
    Regular Contributor
    Join Date
    Mar 2010
    Posts
    136

    record store and file system

    When I learned about record store, I understood that there is no ordinary file system in the small devices . So instead of using file system, we have to use record store for permenant storage.
    When I learned about file system, I suddently remember that fact.

    (1) What kind of mobile device have file system?
    (2) If a device have file system, which one should we use? ( record store or file system ?)
    (3) a record store can do everything what a file system can do?

  2. #2
    Registered User
    Join Date
    Sep 2007
    Location
    Bangalore
    Posts
    868

    Re: record store and file system

    Hi Komomo,

    What kind of mobile device have file system?
    You can know that by using the system properties

    System.getProperty(microedition.io.file.FileConnection.version) If the optional package is supported, a version string is returned. Otherwise "null".
    f a device have file system, which one should we use? ( record store or file system ?)
    It is again depends on your requirement , If you have a huge data need to be written , Then file system will be better and one catch here is it will ask the security question to the user when you are writing the data or retrieving the data, To avoid that you need to sign your application. In case of RMS it is not required, In RMS you can save very small amount of data.

    a record store can do everything what a file system can do?
    AFAI It have its own limitations but it you can do almost all the operation , like search, edit, delete etc...

  3. #3
    Super Contributor
    Join Date
    Nov 2003
    Location
    Bangalore , India
    Posts
    4,429

    Re: record store and file system

    RecordStore cannot store large amount of data where as FileSystem can hold as much as data as remaining memory in the supported device. FileConnection API is an optional API (JSR 75) and RecordStore is widely available in most of the MIDP devices.
    More reading : http://developers.sun.com/mobility/m...s/databaserms/ (little old doc; but to understand the concepts)

    Most of the latest devices support JSR 75 FC API you can check API support in devices from the Device Specifications pages http://forum.nokia.com/devices/
    and also with FC API Expert device search

    The use of RecordStore or FileSystem depends upon your use case, you also have to understand the advantages and disadvantages of using both. If using FileSystem; it would pop up permission messages for file access and you have to Sign your app to avoid these permission messges.

    Yes, RecordStore can do almost every thing FileSystem can do, but as I mentioned previously, RecordStore cannot hold large data.

    Regards
    Gopal

  4. #4
    Regular Contributor
    Join Date
    Mar 2010
    Posts
    136

    Re: record store and file system

    Thanks for the replies.

    RecordStore cannot store large amount of data.
    But why?
    In a file system, information is stored in hard-disk drive?
    In a mobile device, is there a hard-disk drive?

    In which place, recordstore is stored?

    Please don't mind if the question is a stupid one.

  5. #5
    Registered User
    Join Date
    Sep 2007
    Location
    Bangalore
    Posts
    868

    Re: record store and file system

    Hi komomo,

    We have stored more than 3MB data in to our RMS , some people claim they have stored 5MB data in to the RMS .

    -Total memory available to Java applications: some restrict this amount, and leave the rest of the phone memory for native applications like the camera or mp3 player. But that is always something like 5Mb, so that should not be a problem.
    - Maximum size of a RecordStore. This happens for example in all Nokia S40 and almost all Motorola (and other brands). Regarding S40, the size varies with the model, from 32Kb to 262Kb. On Motorola phones some get the limit up to 512Kb per RecordStore. Again that should not be an issue for you as you expect to store just 10Kb.

    In which place, recordstore is stored?
    It will save the record stores in the system folders. That you can't access those. In some phones with the pcsuite you can see.

  6. #6
    Super Contributor
    Join Date
    Nov 2003
    Location
    Bangalore , India
    Posts
    4,429

    Re: record store and file system

    I guess the URL I provided above have some answers already.
    The amount of memory available for record-based data storage varies from device to device. The MIDP specification requires devices to reserve at least 8K of non-volatile memory for persistent data storage. The specification does not place any limits on the size of an individual record, but space constraints will vary from device to device. RMS provides methods for determining the size of an individual record, the total size of a record store, and how much memory for data storage remains. Remember that persistent memory is a shared, scarce resource, so be frugal in its use.
    More info FileConnection vs. RecordStore

    If you had quick search; you could have find most of the answers.

    Regards
    Gopal

  7. #7
    Regular Contributor
    Join Date
    Mar 2010
    Posts
    136

    Re: record store and file system

    Please don't mind for asking like that.

    I will read the URL u have pointed. I just worried that I will not still don't understand even after reading that.
    And the time period I can use net is very limited and worried there is no chance to ask questions anymore.
    And I also worried there is no people who will answer the question when I have the chance to use the Internet.
    That is why I asked the question in a hurry.

    Thanks for the replies.

Similar Threads

  1. exporting and Importing from RMS record Store file
    By knihar in forum Mobile Java General
    Replies: 1
    Last Post: 2010-10-28, 12:59
  2. Store string in Record Store
    By Nourayn in forum Mobile Java General
    Replies: 15
    Last Post: 2010-08-21, 04:08
  3. Encrypting data to store in record store
    By matan_d in forum Mobile Java Networking & Messaging & Security
    Replies: 4
    Last Post: 2009-01-04, 01:21
  4. Record Store vs JDBC. How to store data?
    By 180ºrevolution in forum Mobile Java General
    Replies: 0
    Last Post: 2004-09-17, 15:24
  5. Record Store Management System (RMS)
    By mister318 in forum Mobile Java Tools & SDKs
    Replies: 0
    Last Post: 2004-03-23, 16:38

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
×