Backups, Calculator anomaly

[Derek Atkins]

Look at src/scm/fin.scm

Mike or Penny Novack <stepbystepfarm at mtdata.com> writes:

> Derek Atkins wrote:
>
>>Hi,
>>
>>4,294,967,287 looks amazingly close to 4,294,967,296, which is
>>2^32.  In fact, it's 2^32 - 9.  I'd guess a buffer overrun somewhere.
>>
>>
>>  
>>
> Quite suggestive, since something like 9 would be correct for the
> number of "rents" were the present value 10,000, the rate 6%, and the
> monthly payments around 1140. I can do THAT calc more or less in my
> head. Is this possibly a SIGN error?
>
> I know I promised to join in the effort of looking into things like
> this, but that was back when the time estimate for getting our house
> back together was ..... well let's just say that it still isn't
> finished and all the remaining work is scattered so we have very few
> rooms DONE. No space to begin replacing books (all my computer books
> were in the room that actually burned). But I have actually WRITTEN
> "loan amortization table" programs.
>
> So keep bothering me about this one. Hell, if somebody points out the
> specific code for this function I could look at it anyway (I can READ
> code in most any language even if not fluent enough in the language to
> WRITE effectively). Debugging financial software is what they used to
> to pay me the big bucks for.
>
> Michael
>
>>>  Sound advice. I save GC to a desktop "Finance" folder, and copy from
>>>  time to time to a desktop "backup" folder. Everything is also saved to
>>>  an external hard drive, plus I save critical data every so often to a
>>>  removable SanDisk, which I keep stashed away from my desk. I also
>>>  consider storing saved data outside the house. (Years ago I learned a
>>>  painful lesson about the importance of backups!)
>>>  On another matter: Tools -> financial calculator anomaly... Trying to
>>>  find out how much sooner my mortgage would be paid off by increasing my
>>>  payment, no matter what values I use I get an enormous and wrong
>>>  "payment Periods" result. For example, entering $10,000 as the "Present
>>>  Value," 6% as the interest, $1139.15 as the payment, and zero as the
>>>  "future value" I get 4,294,967,287 "Payment Periods." In fact, no
>>>  matter what values I use I get results of 4 1/4 billion or so.
>>>  Steve J
>>>Message: 11
>>>Date: Tue, 27 Nov 2007 08:27:23 -0500
>>>From: Mike or Penny Novack [1]<stepbystepfarm at mtdata.com>
>>>Subject: Re: Can't Parse
>>>To: Elizabeth Dodd [2]<edodd at billiau.net>
>>>Cc: [3]gnucash-user at gnucash.org
>>>Message-ID: [4]<474C1B3B.4040806 at mtdata.com>
>>>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>>
>>>Some general comments
>>>
>>>
>>>    
>>>
>>>>>Trying going "to a backup file and then move it OUTSIDE
>>>>>your ~/.gnucash tree and then File -> Open it" resulted in the same problem
>>>>>as before, but just on chance I tried something else and it worked fine.
>>>>>Instead of trying to open GC via a data file or via the desktop icon, I
>>>>>went to "Applications" and "Office" and tried it from there. It not only
>>>>>opened immediately, but with the latest data.
>>>>>
>>>>>"All's well that ends well!"
>>>>>
>>>>>Steve J
>>>>>
>>>>>
>>>>>        
>>>>>
>>>> I could only guess that there was a save to the *right* place
>>>> which has saved
>>>>your bacon.
>>>>
>>>>Does the FAQ say "Before upgrading, make a backup of your precious data" ?
>>>> As someone who "lost'" 7 months of data in a hard drive crash I
>>>> know this all
>>>>too well. Re-entering data is very painful and that nearly happened to you
>>>>here.
>>>>
>>>>
>>>>      
>>>>
>>>1) There is no particular reason for you to be having your books (and
>>>the logs and the backups) in any of the GnuCash directories. Just
>>>because that's where GnuCash would have them by default isn't relevant.
>>>If you specify some other directory in which to save the books when you
>>>first create them...
>>>  a) The directory you specify for that is where GnuCash will place the
>>>backups and logs every save.
>>>  b) That directory will be on the list of places you can select when
>>>from within GnuCash you use "open". May need to scroll down to see that.
>>>  c) Having them elsewhere makes it much safer when you alter the
>>>software. But doing this was sort of automatic for me. In this case I am
>>>maintaining books for an organization so of course wanted the data kept
>>>in a directory devoted to that organization's data.
>>>
>>>2) ALWAYS backup all your user data before any software change.
>>>Actually, you should have some regular frequency of doing backups even
>>>if no software change. You decide how much of your data you can afford
>>>to lose/replace --- a month's, a week's, a day's, etc. This advice is
>>>not specific to GnuCash.
>>>
>>>References
>>>
>>>  1. mailto:stepbystepfarm at mtdata.com
>>>  2. mailto:edodd at billiau.net
>>>  3. mailto:gnucash-user at gnucash.org
>>>  4. mailto:474C1B3B.4040806 at mtdata.com
>>>_______________________________________________
>>>gnucash-user mailing list
>>>gnucash-user at gnucash.org
>>>https://lists.gnucash.org/mailman/listinfo/gnucash-user
>>>-----
>>>Please remember to CC this list on all your replies.
>>>You can do this by using Reply-To-List or Reply-All.
>>>
>>>    
>>>
>>
>>
>>
>>  
>>
>
>
> -- 
> There is no possibility of social justice on a dead planet except the equality of the grave.
>
>
>

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available