Corrupted Files

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When you store files onto the PC the calculator also creates two files HP39DIR.CUR and HP39DIR.000. When the calculator asks if you want to initialize the directory it is asking for permission to create these files. It should only do this once per directory that you use to store things. 

The first of these two files mentioned above is not significant but the second contains a list of all the aplets, notes, programs, lists or matrices that you have uploaded to the PC. If these two files become damaged then the objects may still be there but you will no longer be able to access them from the calculator. The most common form of damage is caused when people try to edit these files or when they delete them because they don't realise that they are needed.

The most common symptom of damage is that when you press RECV the calculator asks if you want to initialize when it should not. This can also happen when your calculator's batteries are low, so don't assume immediately that there is a problem. Try fresh batteries first.

One of the earlier page explained the process of creating and editing Notes. If you haven't already read the section on that page called "Doing it the Long Way" then go back and do so now.

The simplest way to repair these files is to delete the files HP39DIR.CUR and HP39DIR.000 and then use the File/Aplet Library command to re-create them. This is generally quick and easy and is discussed in the page "Doing it the Long Way".

Another source of damage is caused when people try to edit Notes in something other than the ADK. Many other programs insert invisible formatting marks which cause the file to become unreadable. If your calculator consistently starts to download a Note and then stops and tells you that it is not an HP file then this may be the problem. The simplest way to fix this is to create a new note, open the new note using the ADK (which won't corrupt it), open the old one in Windows Notepad or in Word and then copy the old information and paste it into the new note.

Note that each of the files stored on the PC also contains a small section of code which is only visible to the calculator when downloaded.  For example, suppose you had a Note containing the text shown on the right.

If you upload it to the PC and then open it in Windows Notepad then you'll see the text shown below left. As you can see there are some code characters that precede the text of the note. The first code of "HP39Asc" identifies it as belonging to an HP39G (or later model) rather than an HP38G and that it is Ascii code (a programming term). This is a little deceptive because the same code is used for all models since the HP39G because their aplets are all interchangable. The next code is a "C" and indicates that it is a note. Various other codes indicate aplets, programs and so on. The next code is the 4 and tells you that the next four characters after the space contain the name of the Note as it is to appear on the calculator. In this case I named the note "TEST". Following that is the actual text of the note. You may like to experiment for yourself by uploading various different objects to the PC and checking them out there. Some of them, such as aplets, are in binary code rather than Ascii code and will not open properly in Windows Notepad. Don't save them if you look at them in Notepad unless you're not worried about them being corrupted.

Last modified: 19 Dec 2007                                             Sitemap        Home        Contact Me