# Data Management

## How much memory should I use for the checkrun?

The memory necessary for a check run is automatically allocated.

## What is the maximum amount of memory that can be used by OptiStruct?

Refer to Memory Handling.

## Can OptiStruct use more memory than I actually have installed on my system (more than installed RAM)?

Refer to Memory Handling.

## What if OptiStruct fails to solve my job, reporting that there is not enough memory available, but my computer has much more memory than required?

Refer to Memory Handling.

## Why did OptiStruct start to run, but fail after some time with a memory allocation error when I used the -fixlen options?

Refer to Memory Handling.

## I have a Windows machine with 3GB (or more) RAM. Can OptiStruct use it? Does it make sense to have more than 2GB RAM installed?

Refer to Memory Handling.

## Will the PC page file size affect the elapsed time for an OptiStruct job?

Yes, the page file size recommended by the vendor is not necessarily the optimal size to run big jobs in OptiStruct. Moreover, if more RAM is installed in a machine, it can process larger page files more efficiently. Changing the page file size is usually recommended to decrease the elapsed processing time.

The elapsed time does not necessarily increase with an increased page file. If too many applications are opened, or if RAM-intensive applications are being used, OptiStruct could be pushed into the swap space, slowing the processing time considerably.

The preferable page file size is: page file size=2*RAM+32 Mb. For example: If the available RAM is 512 MB, the page file size would be 2*512+32=1056Mb.

The maximum page file size is 1500Mb for the 512 Mb RAM.

The page file size can be adjusted as follows:
• Windows 7:

Start > Control Panel > System > Advanced system settings > Settings > Change (on the Advanced tab, under Virtual memory)

Furthermore, it may be beneficial to break up the page file between two disks on a multiprocessor machine (between drives C and D, for example).

Another solution is to put the page file on an SCSI drive rather than an IDE drive. SCSI drives are faster, and will speed up the processing.

## OptiStruct is not recognized as a command or batch file when launched from the Solver Panel within HyperMesh. What do I do?

There are three things you should check in this scenario:
1. Verify that the optistruct.bat file in the <install_directory>\hwdesktop\hm\bin directory is not zero bytes. If it is, replace it with a copy of the file optistruct.bat from the <install_directory>\hwsolvers\optistruct\bin directory.
2. Verify the existence of the system environment variable ComSpec; its value should be C:\WINNT\system32\cmd.exe or equivalent.
3. Verify the existence of the system environment variable PATH; its value should include C:\WINNT\system32\ or equivalent.