How can I reduce the RAM available in XP?

[gismo]

I have an old application that used to run fine on my laptop but after I upgraded the RAM from 1G to 2G it won't run anymore. I did confirm that removing half the memory makes the program work OK and I also tried running it in Win95 & Win98 compatibility modes with no success. Seems like there's got to be a way to fake the program into thinking there's only 1GB in the PC but I couldn't find anything on the web. I suspect the Virtual PC might work but haven't tried that yet. Any ideas?

 

[jesse]

What does it do when you have the 2GB in the laptop?

 

[gismo]

What does it do when you have the 2GB in the laptop?

At program launch I get a dialog box that says "System start-up failed. Please restart Windows." Clicking OK in that box lets the program start but if I attempt to open a file within the program results in an "Application Error" dialog box complaining about rerferencing memory that could not be read. The only choice at that point is to terminate the program. If I remove either of the two 1GB memory modules the program works correctly.

 

[gprellwitz]

If I remove either of the two 1GB memory modules the program works correctly.

I was about to suggest a bad module, but this seems to argue against that. Have you tried switching the modules between the banks?

 

[Keane]

Since it is this application only, I suspect that the developer did some of his own memory management and didn't consider anything above 1Gb of memory as possible. Probably doing some sort of math on it.

What is the application? Are you now running in a 64 bit environment? Sometimes that'll screw things up as well.

The only way to limit system memory is to use the /MAXMEM option in boot.ini, but that affects every app.

I'd recommend some sort of 32bit VM.

 

[gismo]

Since it is this application only, I suspect that the developer did some of his own memory management and didn't consider anything above 1Gb of memory as possible. Probably doing some sort of math on it.

What is the application? Are you now running in a 64 bit environment? Sometimes that'll screw things up as well.

The only way to limit system memory is to use the /MAXMEM option in boot.ini, but that affects every app.

I'd recommend some sort of 32bit VM.

The application is a development tool for Mitsubishi PLCs (MELSEC GP-Win). The copy I have is several years old but IIRC upgrading to the latest version (which would likely solve the problem) costs big bucks and since this is for a home project I don't want to go there.

I'll try changing /MAXMEM in boot.ini to see if that works as this might actually be the easiest option (I rarely use this program).

I created a VM last night but haven't loaded an OS there yet. I haven't done that for a while and am not completely sure how to go about this, any advice would be appreciated.

Also if I set up a XP VM, will I be able to access files and serial ports on the base system?

 

[Steve]

I have similar issue with my 8 year old laptop. 2Gb is above the original RAM spec on the machine. I'm pretty sure it's a BIOS issue and an upgrade would fix it, but the latest upgrade is 7 years old and I doubt a newer one is on the horizon for this machine. It runs fine about 80% of the time and then it'll burp out a BSOD on memory management. The increased memory is worth the aggravation so far as the apps do work better with it in Win7.

 

[jesse]

I created a VM last night but haven't loaded an OS there yet. I haven't done that for a while and am not completely sure how to go about this, any advice would be appreciated.

Also if I set up a XP VM, will I be able to access files and serial ports on the base system?

It depends on the software you use for the VM. Most packages will allow you to bind the serial port to the virtual machine (vmware does permit this).

As far as sharing files - you can do file sharing similar to how you'd do it between two PC's. Vmware also has some kind of drag and drop method of moving files but its way slower.

Just put a XP install disc in your cd rom, start the vm, and tell it to boot from cd. From there it's the same as a regular PC. After it installs be sure to install vmware tools (if you're using vmware) which will take care of all the drivers.

 

[RJM62]

It could be that the program is expecting a certain amount of virtual memory. I forget what obscure program it was, but some years back I encountered an application that wouldn't run once the RAM was upgraded. But manually setting the pagefile size to 1.5 x the old amount of RAM made it work.

I suppose it also could also be that your virtual memory is already set manually to a fixed amount based on the old amount of RAM, which is now "wrong" because of the physical RAM increase. Setting the size to "system-managed" if this is the case may solve the problem. Or maybe not.

In fact, probably not. Either of the above is a longshot. I only came across this problem once, and twiddling with the pagefile size solved it that one time. I have no idea whether it might solve your problem, as well. But it's easy enough to try.

-Rich