48GX computing delay
#1

I have a 48GX which often has a several second delay when performing basic arithmetic. Has anyone else experienced this and is there anything that can be done?

#2

I have a 48GX (several actually), a 48G (again several) and 48G+ (just one). I also have several 48SX models. I would be willing to test out your calculations on these models and time them for you for comparison. Could you give us some details as to what it is you are calculating?

Han

#3

It's usually just basic multiplication or division and it seems to happen pretty randomly.

#4

Wouldn't it be garbage collection? It would especially happen if you don't have much in memory.

Arnaud

#5

I believe you are correct. During garbage collection, the calculator will be seemingly slower. The goal of garbage collection is to get rid of temporary objects in memory which are no longer referenced. If you are low on memory, then the HP 48 will try to garbage collect often in an attempt to get more working memory. Is this the case? Do you have very little free memory?

#6

If you have little memory, the garbage collection will be quite fast as it does not need to tidy much.
However, if you have lots of free memory, it will not happen so often but will take much longer.

Basically, it works like this, the hp leaves all its temporary calculation, objects, rubbish in memory until it feels the memory is too full. It then cleans everything and starts again. If less space (memory) is available, it will have to clean more often but will have less work to do each time and you would not notice it.

When the 49 was introduced with 256 K of free RAM there was lots of people complaining about the garbage collection delay. The solution was to store a huge string in memory to have only say 64K left and adjust the size of this string to your memory requirements. Garbage collection was later improved to cope with the 256K.

Arnaud

#7

Ahh... I truly blundered then. I had assumed that with such little memory, gargabe collection would occur so often that the frequency of gargabe collection was what was noticable. It makes more sense the way you described it.

Just out of curiosity: how did they make the fix for the 256kB of memory?


Edited: 2 Dec 2005, 4:27 p.m.

#8

I believe that the Garbage collector of the 49G was rewritten completely in a ROM update. It still happens but it is much fatser. On the 49g+ I believe it was directly implemented in ARM

Arnaud



Possibly Related Threads…
Thread Author Replies Views Last Post
  Computing pi with the PC-1300S Kiyoshi Akima 0 1,086 11-17-2013, 12:24 AM
Last Post: Kiyoshi Akima
  Apologies on mail delay. Diego Diaz 0 735 11-07-2012, 02:27 PM
Last Post: Diego Diaz
  Books on computing Elementary Functions Nick_S 4 1,593 09-14-2012, 07:33 AM
Last Post: David Hayden
  Computing Square Roots Thomas Klemm 11 2,809 03-30-2009, 03:26 PM
Last Post: Thomas Klemm
  Computing many digits of Pi Juan Pablo Martinez (Spain) 21 4,732 09-24-2007, 10:58 AM
Last Post: Egan Ford
  Computing PI -- a simple programming problem Katie Wasserman 41 8,511 10-20-2006, 10:34 PM
Last Post: Palmer O. Hanson, Jr.
  The risks of retro computing Bruce Horrocks 26 5,510 08-03-2006, 02:24 PM
Last Post: Bill (Smithville, NJ)
  computing chances Bram 4 1,319 04-16-2006, 01:25 PM
Last Post: Bram
  Timer function for repeated delay? Marcus von Cube, Germany 7 1,796 01-21-2006, 12:57 PM
Last Post: Marcus von Cube, Germany
  1980s Vintage computing - new HP-9915 page and disassembler John 0 642 12-19-2005, 09:00 PM
Last Post: John

Forum Jump: