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#1
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How can OS X TAKE up 400meg of Ram to operate?
I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned
off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? (just curious - I can't believe the os is taking 400meg with nothing running) -mike |
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#2
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It's a Unix variant, if the memory is available the OS will take it up, when
the memory is needed it will swap unused portions out to disc. Unices tune they're memory to need. Hope that helps Chris "Michael Droste" wrote in message om... I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? (just curious - I can't believe the os is taking 400meg with nothing running) -mike --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.711 / Virus Database: 467 - Release Date: 6/26/2004 |
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#3
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#4
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Michael Droste wrote:
I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? To quote one of the guys from Sun Microsystems, "free memory is wasted memory". I don't know a lot of technical detail about the memory model on OS X specifically, but on many modern operating systems, memory that isn't otherwise in use gets used by the operating system as a giant disk cache. Then, if some program wants to come along and use the memory "for real", the OS just tosses out some of the data in the disk cache and repurposes that memory, putting it into the free memory pool. It's kind of like what you'd do if you had $10,000. You wouldn't keep it all in your checking account. To make the best use of the money, you want to keep only something like $2,000 in the checking account to cover a month's expenses, then transfer the rest into some kind of account where you can make the money work for you, like maybe a linked savings or money market account where you can at least earn a little interest. The OS is doing the same thing with memory, except that it's using it to gain better disk performance. I probably should reiterate that I'm talking in general terms, not about OS X specifically, although I did just poke around a bit with Terminal and it seems like OS X does work this way... - Logan |
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#5
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In article ,
Michael Droste wrote: I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? Dunno. Open a terminal window and do a ps -ale and see what processes are using what memory. There is a freeware application called 'top' which is more convenient but basically gives the same information. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#6
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#7
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Scott Dorsey wrote:
...snip.. Dunno. Open a terminal window and do a ps -ale and see what processes are using what memory. There is a freeware application called 'top' which is more convenient but basically gives the same information. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." ....and a windoze version called wintop. Later... Ron Capik -- |
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#8
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Pat Janes wrote:
Top is installed in OS X. Open terminal, type 'top', hit the return key. Or type "top -s5" instead if you don't want it to use the ridiculous default of updating the display once a second. It's not much use to have the display if it's changing so fast you can't read it, and it's also not much use if "top" is using 33% of the CPU power just to make the list. I don't know why the OS X version of "top" is apparently such a CPU hog compared to all other versions I've ever used... - Logan |
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#9
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And to paraphrase that from IBM guys in the old days, free cpu cycles are
wasted cpu cycles. When it comes to optimization of systems, any free ram or cpu cycles are wasted, but when it comes to an interactive system like a PC, most people simply want the opportunity to run what they want when they want. That means lots of extra available ram and cpu cycles. ****, we ought to get down on our knees and praise the cpu/memory gods that we have systems on our desktops that exceed anything that Mr. Grove or other computer pundits foresaw the need for. On the other hand, wasted cycles could be doing other compute intensive work like SETI@ home. I have no problems with sharing my unused time with SETI. Perhaps there are other avenues of globally using wasted CPU time and we'd come up with something worth the effort. -- Roger W. Norman SirMusic Studio "Logan Shaw" wrote in message ... Michael Droste wrote: I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? To quote one of the guys from Sun Microsystems, "free memory is wasted memory". I don't know a lot of technical detail about the memory model on OS X specifically, but on many modern operating systems, memory that isn't otherwise in use gets used by the operating system as a giant disk cache. Then, if some program wants to come along and use the memory "for real", the OS just tosses out some of the data in the disk cache and repurposes that memory, putting it into the free memory pool. It's kind of like what you'd do if you had $10,000. You wouldn't keep it all in your checking account. To make the best use of the money, you want to keep only something like $2,000 in the checking account to cover a month's expenses, then transfer the rest into some kind of account where you can make the money work for you, like maybe a linked savings or money market account where you can at least earn a little interest. The OS is doing the same thing with memory, except that it's using it to gain better disk performance. I probably should reiterate that I'm talking in general terms, not about OS X specifically, although I did just poke around a bit with Terminal and it seems like OS X does work this way... - Logan |
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#10
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On 2004-06-30, Michael Droste wrote:
I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? I don't have a FreeBSD^H^H^H^H^H^H^HMac OS X box at hand to check but on Linux, memory that is being used to cache disk data is not counted as "free". Even though it is, in the sense that if a process needed it, it would be instantly reclaimed. As Scott said, top(1) will give you more information. Hit "M" to make it sort processes by memory usage (by default, it sorts the them by CPU usage). (just curious - I can't believe the os is taking 400meg with nothing running) Not yet, but they're working on it. -- André Majorel URL:http://www.teaser.fr/~amajorel/ Respect for government [...] and its symbols is fundamentally fascist. -- William Sommerwerck, on the subject of ****ing on a national flag. |
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#11
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On 2004-06-30, Michael Droste wrote:
I have a 733hz g4 mac osx 10.3.4 - with almost all my fonts turned off. I'm a using Konfabulator Widget that states only 1.12g is available. Why? Just asking, what about turning Virtual Memory off? I don't know, but will it cause trouble with OS 10? I use OS9.2 and DP3.01 with MOTU 24i and have been instructed to turn it off. |
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#12
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Raymond wrote:
Just asking, what about turning Virtual Memory off? I don't know, but will it cause trouble with OS 10? I use OS9.2 and DP3.01 with MOTU 24i and have been instructed to turn it off. In a very real sense, on most modern Unix-like OSes there is no such thing as being able to turn virtual memory off. The memory model is quite different than on OS 9.x. When you invoke a program, you don't load it into memory like on OS 9.x; instead, you tell the operating system to create a mapping between the virtual memory address space of the program and the file that contains the executable. Then the memory management unit of the processor takes care of loading pieces as they are needed. If certain portions of the executable are never used, they will probably never be loaded from disk. Likewise, even if they are loaded, if memory gets low the OS may discard the pages and later (if necessary) load them again directly from the executable file. An older type of virtual memory system would only ever page things out to a dedicated virtual memory paging file; you can turn off the virtual memory paging file in OS X, I suppose, but even if you do so, you are not turning off virtual memory completely. Anyway, the point is that in OS X, virtual memory is not just an added featu it's such an integral part of the OS that basic things like just launching programs use it to get their work done. Once again, I should insert the disclaimer that I'm more of a Unix person who happens to use OS X now, so I'm extrapolating and assuming this applies to OS X to some extent, but I'm pretty confident that it does apply since it is, after all, largely based on FreeBSD. However, the situation is made more complicated since Mach is involved. - Logan |
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#13
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Logan Shaw wrote in message ...
It's kind of like what you'd do if you had $10,000. You wouldn't keep it all in your checking account. To make the best use of the money, you want to keep only something like $2,000 in the checking account to cover a month's expenses, then transfer the rest into some kind of account where you can make the money work for you, like maybe a linked savings or money market account where you can at least earn a little interest. ??? You mean my wife has been right all this time? |
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#14
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Logan Shaw wrote in message ...
Raymond wrote: Just asking, what about turning Virtual Memory off? I don't know, but will it cause trouble with OS 10? I use OS9.2 and DP3.01 with MOTU 24i and have been instructed to turn it off. In a very real sense, on most modern Unix-like OSes there is no such thing as being able to turn virtual memory off. The memory model is quite different than on OS 9.x. When you invoke a program, you don't load it into memory like on OS 9.x; instead, you tell the operating system to create a mapping between the virtual memory address space of the program and the file that contains the executable. Then the memory management unit of the processor takes care of loading pieces as they are needed. If certain portions of the executable are never used, they will probably never be loaded from disk. Likewise, even if they are loaded, if memory gets low the OS may discard the pages and later (if necessary) load them again directly from the executable file. An older type of virtual memory system would only ever page things out to a dedicated virtual memory paging file; you can turn off the virtual memory paging file in OS X, I suppose, but even if you do so, you are not turning off virtual memory completely. Anyway, the point is that in OS X, virtual memory is not just an added featu it's such an integral part of the OS that basic things like just launching programs use it to get their work done. Once again, I should insert the disclaimer that I'm more of a Unix person who happens to use OS X now, so I'm extrapolating and assuming this applies to OS X to some extent, but I'm pretty confident that it does apply since it is, after all, largely based on FreeBSD. However, the situation is made more complicated since Mach is involved. - Logan Thanx! This answer explains it the best for me - So it's kind pre-formating or getting ready to use other programs or information - I remember os9 used to take a whopping 32meg of ram!  -mike |
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#16
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On Fri, 02 Jul 2004 08:14:45 GMT, Logan Shaw
wrote: In a very real sense, on most modern Unix-like OSes there is no such thing as being able to turn virtual memory off. The memory model is quite different than on OS 9.x. When you invoke a program, you don't load it into memory like on OS 9.x; instead, you tell the operating system to create a mapping between the virtual memory address space of the program and the file that contains the executable. Then the memory management unit of the processor takes care of loading pieces as they are needed. If certain portions of the executable are never used, they will probably never be loaded from disk. Likewise, even if they are loaded, if memory gets low the OS may discard the pages and later (if necessary) load them again directly from the executable file. An older type of virtual memory system would only ever page things out to a dedicated virtual memory paging file; you can turn off the virtual memory paging file in OS X, I suppose, but even if you do so, you We've been through all this (in a Windows context) recently in another group. Yes, virtual memory is a basic concept of Windows, (and now, at last, apparently of MacOS). But, particularly when running applications that require real-time data streaming (like music and video recording) you don't want the os to be perpetually swapping code modules on and off disk. And, fortunately, as long as adequate physical memory is installed, it won't. Virtual addressing does not equate to continual swapfile (or any other euphemism for disk memory) usage. CubaseFAQ www.laurencepayne.co.uk/CubaseFAQ.htm "Possibly the world's least impressive web site": George Perfect |
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#17
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Laurence Payne wrote:
Yes, virtual memory is a basic concept of Windows, (and now, at last, apparently of MacOS). huh? How about VMS (Virtual Memory System) on a VAX in 1978? IBM's VM/370 in 1972? And it's been on Macs for quite a while, since OS8 at least. |
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#18
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so what wrote:
Laurence Payne wrote: Yes, virtual memory is a basic concept of Windows, (and now, at last, apparently of MacOS). huh? How about VMS (Virtual Memory System) on a VAX in 1978? I think by "basic concept of Windows" he means "concept that's integral to Windows", not "concept that originated with Windows". - Logan |
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#19
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so what wrote:
Laurence Payne wrote: Yes, virtual memory is a basic concept of Windows, (and now, at last, apparently of MacOS). huh? How about VMS (Virtual Memory System) on a VAX in 1978? IBM's VM/370 in 1972? And it's been on Macs for quite a while, since OS8 at least. VM/370 wasn't a virtual memory system, it was a complete virtual machine system that allowed you to run several different individual operating systems on one piece of hardware without them interacting at all. It was a brilliant idea (and some of the operating systems that run under VM, like CMS and TSS but not MVS, can do virtual memory too). --scott "Our 360/50, it pleases us plenty We got it last week to replace the 370..." -- Stan Kelley-Bootle -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#20
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Scott Dorsey wrote: VM/370 wasn't a virtual memory system, it was a complete virtual machine system that allowed you to run several different individual operating systems on one piece of hardware without them interacting at all. To be fair, it was a virtual memory system with a hypervisor, CP, that supported multiple virtual machines by trapping the priveledged instructions. That it could support virtual memory on top of virtual memory was rightous. It was a brilliant idea (and some of the operating systems that run under VM, like CMS and TSS but not MVS, can do virtual memory too). Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |
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#21
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On 2004-07-03, Bob Cain wrote:
Scott Dorsey wrote: VM/370 wasn't a virtual memory system, it was a complete virtual machine system that allowed you to run several different individual operating systems on one piece of hardware without them interacting at all. To be fair, it was a virtual memory system with a hypervisor, CP, that supported multiple virtual machines by trapping the priveledged instructions. That it could support virtual memory on top of virtual memory was rightous. It was a brilliant idea (and some of the operating systems that run under VM, like CMS and TSS but not MVS, can do virtual memory too). MVS had not virtual memory ?? Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. How different would that be from running one of the two within VMware ? (assuming you don't need direct access to peripherals other than disks). Or is sharing peripherals the whole point of the hypervisor ? -- André Majorel URL:http://www.teaser.fr/~amajorel/ Respect for government [...] and its symbols is fundamentally fascist. -- William Sommerwerck, on the subject of ****ing on a national flag. |
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#22
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Bob Cain wrote:
Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. Actually, the Pentium has a lot of the stuff needed for virtualization built into it, but nobody has actually implemented any of it. I do know that the virtual machine stuff under Linux works surprisingly well. I have seen folks not only boot up Windows under Linux, but I have seen them boot one version of Linux up under another. But this is not true virtualization, although it works a lot faster than I ever expected, because you have a compatibility process that is intercepting hardware access and routing it through the master OS. --scott Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#23
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Andre Majorel wrote: MVS had not virtual memory ?? Sure did. I think Scott is saying that MVS doesn't run on VM/370. That my be true now but I know that it once did because that was how the developers developed it. I worked for them in Poughkeepsie when that effort was ongoing. I was on the hardware side but my girlfriend worked on MVS. Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. How different would that be from running one of the two within VMware ? (assuming you don't need direct access to peripherals other than disks). I need to check out VMware. Don't know enough about it. Or is sharing peripherals the whole point of the hypervisor ? Well, on the VM/370 systems about the only peripherals are the direct access storage devices and the communications controlers which can be handled quite specifically. It probably is another can of worms to share the breadth of peripherals found across typical PC systems. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |
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#24
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Scott Dorsey wrote: Bob Cain wrote: Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. Actually, the Pentium has a lot of the stuff needed for virtualization built into it, but nobody has actually implemented any of it. The problem is most likely the device sharing problem that Andre brought up. I do know that the virtual machine stuff under Linux works surprisingly well. I have seen folks not only boot up Windows under Linux, but I have seen them boot one version of Linux up under another. But this is not true virtualization, although it works a lot faster than I ever expected, because you have a compatibility process that is intercepting hardware access and routing it through the master OS. Fascinating. I didn't know Linux had VM support. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |
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#25
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Bob Cain wrote:
Fascinating. I didn't know Linux had VM support. Linux has special support for running other Linux instances within your main Linux instance. It's called User-Mode Linux. It's not quite the same thing as a real virtual machine from what I understand. Other Unix systems are starting to have similar features. I beleve AIX already has one, and Solaris 10 will have a feature called "zones" where you can start up extra zones at a runtime and assign different priorities to them, etc. They are all separate instances of Unix, but I believe there are certain subtle interactions you'll see. For example, you can, I think, cap the physical memory used by each zone, but if you have 1 GB of RAM and three zones capped at 512 MB each, you can still "feel" the presence of the other zones from within one zone. Plus I also believe (although, again, could be wrong) that no process ID will ever exist in more than one zone at once. In practice, this wouldn't be any problem since there are no guarantees about what order process IDs are chosen in, but the point is that the zones (or the User-Mode Linux instances) aren't separate operating systems; they are tightly-integrated instances of the same operating system. - Logan |
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#26
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Bob Cain wrote:
Andre Majorel wrote: Sure did. I think Scott is saying that MVS doesn't run on VM/370. That my be true now but I know that it once did because that was how the developers developed it. I worked for them in Poughkeepsie when that effort was ongoing. I was on the hardware side but my girlfriend worked on MVS. No, MVS definitely ran (and still does run) under VM, but I didn't think it had real virtual memory. It's been a long time, but I remember writing all these overlays for everything. But I was in high school, working on a 360/50, the last time I actually touched OS. Brilliant it was. Would that someone would to a VM hypervisor for the Wintel architecture so that I could run Win98SE and XP concurrently when I have to for the newer damnable, heinous upgrades and applications that require XP. How different would that be from running one of the two within VMware ? (assuming you don't need direct access to peripherals other than disks). Very different, in that you now have no way for one operating system to take over the machine.. the hardware is basically enforcing the virtualization rather than the software doing it. And VMware does do a remarkably good job of simulating direct access to peripherals and allowing badly-written code to run in the sandbox. The problem is that doing this is slow because you have a whole bunch of other layers intercepting this stuff. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
or something similar sorry its been a while)
Linear Mode
