On Jan 3, 2006, at 2:15 PM, Lee Larson wrote: > On Jan 3, 2006, at 11:44 AM, R. D. Preston wrote: > >> Is anyone up for a convo concerning System Memory? ? and why my >> 'Inactive' >> memory grows, while the 'Free' memory slowly dwindles to the >> point of being >> exhausted. I've noticed this while watching 'Activity Monitor' >> in System >> Memory mode during my modem-hangup problem. > > What you're seeing is normal and desirable behavior for a Unix > system. All Unix systems try very aggressively to use all your RAM > all the time. The idea is that unused RAM is being wasted, so they > cache all sorts of useful things there, such as recently opened > files, system libraries and networking information. This RAM can be > freed up very quickly, if it is needed by a program. In the mean > time, it is available hundreds of times faster than through a disk > access.
Yes, OK, I'm with you so far... > You can look at the memory allocation by opening up a terminal > window and typing 'top'. Here's part of what my PowerBook shows: > > PhysMem: 64.3M wired, 122M active, 286M inactive, 474M used, > 550M free > VM: 3.83G + 128M 26028(0) pageins, 0(0) pageouts Roughly similar to my own numbers. Also displayed in the 'System Memory' mode of Activity Monitor. ( 2nd attempt: apparently, the server belched on a small graphic attachment ) > Here's what each of the categories means: > > wired This is memory that's used all the time and is never freed > up. It's where the operating system kernel lives. > > active This is allocated for use and has actually been used recently. > > inactive This is allocated for use, but has not been used recently.. > > used wired+active+inactive > > free Not yet used for anything. > > > > Since the power died last night, I just rebooted the machine for > the first time in ages. That's why the free memory is so large. as > I continue to use the machine, more stuff will get cached, and the > free memory will dwindle. This is a good thing because frequently > used data is being cached. As this happens, the whole system speeds > up because your machine doesn't have to go to the slow hard drives > as often. This is one reason why I hardly ever shut down a Mac OS X > machine. People who shut down their machine every night may be > taking a performance hit. Ok; now... I've been seeing the Wired and Active categories remain relatively the same, but the Inactive has grown to the point of only a smidgen of Free remaining, a number of times. After continuous hours of d/l operation, is this contributing to the changes I see? I usually just log out when the 'puter is idle. Machine config.: Mac Mini, 1.42 GHz, 1 GB RAM OS X ver. 10.4.3, from ext. 80 GB Firewire My common apps: dial-up / continuous eMail / continuous encryption / continuous newsreader for d/l's / continuous Activity Monitor / continuous Occasional apps: mus & vid players / run & quit viewers / run & quit browser / run & quit text editor / run & quit > Don't worry about your memory unless the pageouts number in the top > display gets big. This is the indicator that shows you're using all > your RAM and then some. > > > > Here's the same top information 10 minutes later. All I was doing > in the interim was reading email, typing this message and printing > a pdf. > > > > PhysMem: 66.4M wired, 226M active, 552M inactive, 746M used, > 350M free > VM: 3.94G + 128M 26868(0) pageins, 0(0) pageouts The time span I'm seeing is somewhere after 7, 8, 9 hrs., etc. Regards, Russ Preston | The next meeting of the Louisville Computer Society will | be January 24 at Pitt Academy, 6010 Preston Highway. | The LCS Web page is <http://www.kymac.org>. | List posting address: <mailto:macgroup at erdos.math.louisville.edu> | List Web page: <http://erdos.math.louisville.edu/macgroup>
