Problem running analyses that use large amounts of memory
Question
I tried to run an analysis option in OSLO with ever increasing calculation resolution. However, at a certain point, OSLO doesn't appear to be able to do the analysis and appears just to hang. I have to force OSLO to stop by using the MS Windows Task Manager. What is happening? How can I correct this behaviour?
Synopsis
Problem running analyses that use large amounts of memory
Symptoms
"As you increase the memory demands for a specific calculation in OSLO, OSLO requests and is granted the additional memory from MS Windows. If the memory demand is too great for the RAM memory of your computer, Windows starts "paging" the data to your hard disk (so-called "virtual" memory). The OSLO calculations continue, but whenever virtual memory is invoked, the calculation speed slows to a crawl as much of the computer's time is spent swapping pages of memory. The OSLO calculation should eventually conclude properly, but the length of time could be one hundred to one thousand times longer."
Workaround
"MS Windows does not alert OSLO that virtual memory is being used, and as a result, OSLO cannot alert the user that this is the case. There are two things which you can do to help this situation:
Increase the amount of RAM
Decrease the size of your virtual memory paging file to be very small. MS Windows does a check on the size of the paging file when allocating virtual memory and if it is too small, MS Windows will not allow virtual memory to be allocated and issues a warning message and stops further analysis (OSLO handles this exit from the calculation gracefully). You can decrease the size of your virtual memory paging file by performing the following steps from the Windows start menu: Start>>Settings>>Control Panel>>System>>Advanced>>Performance Options>>Change: Paging File Size for the selected drive: Initial size (MB) = 2 Maximum size (MB) = 2
You might not want to keep the size of the Virtual Memory paging file so small on a permanent basis (other programs may benefit from it is large). However, this is a good exercise to follow to find out when your computer switches to virtual memory during OSLO calculations. "
