Memory Allocation

P

Peterk2004

Registered
I used to think having the system decide important things was a good thing. Memory allocation in Os9 was alright,but having to change settings from the minimum values to more realistic ones got to be a pain because you had to do everything manually. But always believed having more ram was better for my needs than a system that used virtual memory the most.

I wish I still had the option to manually adjust those values. The machine is a Dual core 2.3GHz G5 with 6.5 Gigabytes of Ram installed. I use this machine primarily for graphics (photoshop and 3Dsoftware) I will seldom have more than 3 or 4 applications open at once and have chosen not to have a permanent internet connection. I use a program called Daz3D a lot and info in the Activity Monitor tells me it uses about 800 megabytes of VM and about 300 megabytes of real ram.

Seems such a shame so much of my ram is not being used in place of the virtual memory. Since it is available, why can't the system, which is supposed to be smarter now with Os 10.49, use the ram instead of the slower hard disk? How can I get this program to use more real ram? I don't care if I have to go into the terminal to do it. 3D applications can really push a machine to the maximum and I would like it too work smarter than it seems to be now. How can I do this? I have the 7800 GT Nvidia video card which is supposed to help here too. Just don't think it is being fully utilized either. How can I tell?
 
The rules of allocating 'minimum size' and 'maximum size' amounts (of RAM), based on the 'suggested size' and type of application was not too complicated; nor, of a hassle.
A Mac (truly) running System 9.2.2 (not 'Classic'), and proper application memory allocations - runs circles over MacOS X. The one noted deficiency of System 9.2.2 and earlier - is / was the inability of reclaimed allocated RAM (due to quitted applications) from being summed into a single RAM block.

The above is now hind sight, since MacOS X does not permit users' the (manual allocation) luxury.

Why (for example) 'System Preferences' (428 KB) displaying 'UniversalAccessPref.prefPane's (464 KB) panel requires 27.91 MB of actual RAM, and 124.98 MB, is ... insane. It is also an indication of the continuing level of incompetence of various personal of the NeXTStep OS mentality.
 
I guess the hassle of manually allocating min and max ram values was only bothersome to me at the time because I was installing so many new things all the time. In hindsight, I never really had any trouble after setting the priorities I wanted the first time. The systems ability to put to use unused ram just boggles my mind. I am hoping the unadvertised method of getting into the settings and shifting the balance of ram usage is still a possiblity.
 
Memory management in OS X is vastly superior to OS 9. You don't need to worry about it. Your application may show 300MB of RAM being used but this also includes RAM for shared libraries. In Activity Monitor, add the Private memory column to see the RAM that is actually owned by that application.

Also, the amount of virtual memory shown there isn't necessarily what is used on the hard drive. Mine shows 9GB virtual memory used but the size of /var/vm is 2.5GB. The virtual memory number shown seems to actually represent what the OS assigns to the application. When the app opens, the OS reserves some address space for the application for future memory allocation.

You can't change the behaviour of the memory management short of downloading the Darwin kernel source and replacing the memory management subsystem yourself.

A good read:
http://www.macosxhints.com/article.php?story=20010613140025184
 
Another big contributer in this is memory mapped libraries and files. Basically under OS X everything is demand loaded. Many parts of your program are just copies of what is on the hard drive, so rather than loading all that into memory when the program starts only those parts that are needed actually get copied into RAM.
 
You must log in or register to reply here.
Back
Top