Why mirror the data? Just work the data directly on the SD card. If the unit goes down for whatever reason, you data will be safe. With a large enough card, you could also run periodic system backups.
----- Original Message ----- From: "Danny Wong" <[EMAIL PROTECTED]> To: "Palm Developer Forum" <[EMAIL PROTECTED]> Sent: Wednesday, February 26, 2003 10:56 AM Subject: RE: Data backup suggestions > HI Brad, > > You can easily mirror what you are doing to the card. > When a new record is created you can write the same record to the card. > You don't have to use a big file. You can have the same data structure on > the card. Basically it will be an .pdb. > > regards, > > danny > www.toysoft.ca > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of Brad > > Figler > > Sent: Wednesday, February 26, 2003 8:50 AM > > To: Palm Developer Forum > > Subject: Data backup suggestions > > > > > > All, > > > > I am tossing around some ideas for doing on the fly data backup to an > > SD/Flash memory card. Our product is going to be hosted on a palm device > > (m515 or Tungsten). The device is going to be mounted inside of an > > establishment, that most likely will not have a computer (and the > > employees > > most likely won't know how to use one, so hot sync is out). It > > is going to > > be collecting data that will be stored in various databases on the palm > > device. I am thinking about mirroring every piece of data that we collect > > on an SD card as we collect it. I know that I cannot write to an SD card > > using the Data Manager, but I can open a file using the VFS Manager. So > > what I had in mind was creating a binary file large enough to hold a > > pre-defined maximum number of fixed size records and every time a record > > gets added to the database on the palm unit (in user storage) I > > would mirror > > the binary chunk inside the file on the SD card. I have multiple > > databases, > > so I would need to have anywhere from 2 - 5 file handles open at one time. > > The largest single record being written at any one time will probably be > > less than 100 bytes, so I am assuming (I know, I know) that the > > performance > > hit won't be that bad. Plus, the device is not going to be > > interacted with, > > so the user is not going to notice if it takes 100us vs. 10us to add the > > record. > > > > Please give me your thoughts and suggestions on this method > > or any other > > method that you can suggest. I have not written any code to write to an > > expansion card yet, so I am basically on a fact finding mission to see if > > what I am planning to do is feasible. > > > > Thanks in advance, > > > > Brad > > > > > > > > -- > > For information on using the Palm Developer Forums, or to > > unsubscribe, please see http://www.palmos.com/dev/support/forums/ > > > > > > > -- > For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/ > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
