Virtual Memory

[Deleted]

WHat is virtual memory all about? I keep getting a pop up that says Window Virtual Memory is low. Windows is increasing paging file some applications might not work.

[Clipper]

www.askdavetaylor.com/how_can_i_fix_too_little_virtual_memory_in_windows.html

I had that problem a year or so ago Alan. A friend here performed the tasks described here in the link from Dave Taylor. He dumped and reloaded my Firefox, and a couple of other applications I was using. I have not had the problem since, and since Ralph cleaned up my hard drive and thinned out the number of useless things I had running in the background I have no problem.

Ralph and others have told me that installing some more RAM would speed things up considerably and preclude that problem also.

[dgriffin]

I remember sitting in a lecture on Virtual Memory back in the early 70's and was totally awestruck at it's simplicity and elegance. That said, it ain't easy to explain. I'll try to simplify it.

Even back then a computer was mostly wasted resource, its processor or "brain" zipping along at unGodly speeds, but only after waiting for the data to arrive from input-output devices like tape drives or hard disk drives or, after the advent of interactive users, waiting for some guy to pull his finger out of his nose and choose the color sweater he was ordering from LL Bean.

Most of the time, all this high priced large-scale-integrated computer circuitry sat idle in early computers that ran in "batch" mode, meaning one program at a time. Until someone had the bright idea of running multiple programs at once. While one program was waiting for data from a slow input-output device, the processor could be serving another program that was ready to go. Engineers devised a way to allocate some of the memory and some of the processor cycles to each program. The customer paid money for more memory but was happy the utilization of his expensive processor jumped from 25 to 85% by running multiple programs at the same time.

This was called MultiProgramming and it helped companies like IBM sell more memory and higher speed processors and make lots of money. A customer could run his payroll program at the same time he was running accounts payable and his truck route scheduling.

So looking at it from a memory point of view, let's say you were running 4 programs and each needed a gig of memory for a total of 4 gigs of memory. Soon processors got so fast they could easily handle all of that and more. Well, you could buy more memory and run even more programs, but maybe you didn't need that capacity all the time, every day. What you needed was a dynamic allocation of memory and a way to PRETEND you had more memory than the physical amount in the computer. Thus was born VIRTUAL memory.

Let's say that in the scheme of things you have a program that needs 4 gigs of memory but you only have 1 gig available because other programs are running at the same time. In Virtual Memory, you break the program that would sit in memory into logical pieces and store them on the hard drive. Then you roll in each section as you need it. So for example, you can run a 4 gig program in 1 gig, because it's divided into pieces which you can roll out and and roll in as you need each piece. That means in one gig of REAL memory you have 4 gig of VIRTUAL memory. (Don't take those proportions seriously; I'm doing this from long ago memory.)

Today, in modern programs such as Windows, just about everything is designed to run in Virtual Memory. Now that can be a lot of rolling in and rolling out program pieces between the hard drive and memory, right? That takes time. The more REAL memory you have, the less you have to roll pieces of the program in and out and they can be bigger pieces. And that's the reason why additional REAL memory speeds up your PC. With more real memory, you save all that waiting for the next section of the program to roll into memory.

Hope that helped.

[Ralph]

The programs on your PC run by using the RAM installed in your system (as well as the CPU). Many times when programs run out or RAM they access your hard rive and use the memory there, which is basically "virtual memory". Virtual Memory is usually allocated about 1.5 to 2 times the RAM on your PC.

Usually the "low virtual memory" means you need more RAM, since you are accessing the hard drive to run tasks/programs. But this can be caused by your hard drive being damn near full, or by simple misconfigurations on what you system is using.

If the free space on your hard drive is less than 10 - 20% you can run out of virtual memory real quick! If your configurations have been altered, either by a third party or by a virus/trojan/maleware/etc it will cause it also.

Usually the addition of extra RAM (provided your PC is not infected or the hard drive chuck full) can clear the problem up. Limited hard drive space is usually cause by downloading too many songs or videos......they take up LOTS of space.

[Deleted]

Thanks. My free space on C is 60.1GB and my used space is 10.2GB

[chris]

Dave that was an excellent description of virtual momory. You should have been (would have been a great teacher) Thankyaverymuch.

[dgriffin]

Jan 4, 2012 16:03:38 GMT -5 @alanquigly said:

Thanks. My free space on C is 60.1GB and my used space is 10.2GB

Thanks, Chris.

Alan, hard drive space won't be your problem and you're only using a sixth of it at the moment. Do you know the size of your physical memory, sometimes called RAM? Too little will slow you down. These days 1 gig is almost minimum. Although I've run fine with as little as 256 meg as long as I wasn't doing anything complicated.

[Deleted]

2.60GHz 256MB Ram

[dgriffin]

Yup, 256 meg of memory is pretty small for today's computers. I was running that memory at one time, as mentioned above, but could not use a quality virus scan at the same time. And then I would bring up MSPaint, Gimp and Google Earth while I went out for coffee and waited for everything to come up!

So, what happens when your machine is trying to run just about everything in virtual memory, is that the "paging," as it's called, of program sections on and off the hard drive becomes enough to slow everything down. A couple of things you can do for temporary relief are to exit programs you're not using, shut down your browser periodically and restart it (browsers have what are called "memory leaks" and firefox is notorious for them) check your msconfig to reduce programs that automatically load when you turn on the computer (start/run/type in "msconfig" without quotes, choose the Startup tab and uncheck any program YOU RECOGNIZE and that you know you don't need - if you don't know what it is, don't turn it off) and if Jon were here he'd tell you to switch to Linux! (So would others.)

[dgriffin]

I don't want to get too complicated here, but to be complete in what I said about msconfig, you can also choose the Services tab, check "Hide all microsoft" services (which are the essential ones) and uncheck any that are left. When you find something is missing in the use of your PC, you can go back in and turn it on, although it may turn itself back on. Or you will never miss it, in which case you're better off.

[Deleted]

Jan 5, 2012 10:34:16 GMT -5 @dgriffin said:

Yup, 256 meg of memory is pretty small for today's computers. I was running that memory at one time, as mentioned above, but could not use a quality virus scan at the same time. And then I would bring up MSPaint, Gimp and Google Earth while I went out for coffee and waited for everything to come up!

So, what happens when your machine is trying to run just about everything in virtual memory, is that the "paging," as it's called, of program sections on and off the hard drive becomes enough to slow everything down. A couple of things you can do for temporary relief are to exit programs you're not using, shut down your browser periodically and restart it (browsers have what are called "memory leaks" and firefox is notorious for them) check your msconfig to reduce programs that automatically load when you turn on the computer (start/run/type in "msconfig" without quotes, choose the Startup tab and uncheck any program YOU RECOGNIZE and that you know you don't need - if you don't know what it is, don't turn it off) and if Jon were here he'd tell you to switch to Linux! (So would others.)

Thanks I checked that mscong thing but it says it is running just minimun startup. I do have been having the same thing in terms of getting that mesage when I am using virus scan or when an update is going on.

[dgriffin]

Yes, sounds familiar. Well, recycle your browser once in a while (exit and re start.)

[Ralph]

Dave pretty much nailed it. Windows XP (if that is what you are running) requires 256MB just to turn on and run, that is the minimum requirement. Regardless of HD space, pretty much anything you do after booting up the PC will require virtual memory to run.

[chris]

I have virtually no memory at all. A couple weeks ago I went to a workshop only to find out that I was 1 week early. Yesterday I went to a Dr appt only to find out that it was really today. My brain cells are slowly dying. ;D (sorry off topic but couldn't resist the oppoutunity)

[clarencebunsen]

I'm still waiting to get that USB port installed in my head so I can make use of a jump drive to overcome those pesky memory lapses.