What is virtual memory? - Gary explains 

when you are taught the same in class but Gary explains better 😀

Knew most of this from the course in Operating Systems in the University, but it is always nice to hear Gary explain stuff. And I got to repeat the things I knew too. Please never stop making these videos, Gary! :D

Don't know how much AA pay you, Gary, but you should get a pay rise

I never would have thought I would end up going to Android Authority to help study for my OS' exam... As always Gary your videos are probably the best on AA. Keep it up!

Playlist of Gary explains, the best ever !

Gary, you are a marvelous teacher. Clear, concise, precise, relaxed, happy... and no irritating "RU-vid persona". From an engineer, let me tell you this - you *really do* sound like you know your subjects well, so thank you for being you and for articulating so effectively and clearly. You are an asset to the engineering world. God bless you! 😀 Matthew, England.

excellent tutorial. I've been working on computers since 1980 and never have heard this explained so clearly as you did in this video. love the charts and diagrams as well as those really help! and the funny kids pics made me laugh. cheers! 😎

It's always a pleasure listening to your explanations Gary. Keep up the good work :D

This has been the best of Gary Explains vids Nice job sir .....

Thanks Gary! This was clear and complete and much more interesting than the same topic coverage in class.

After a Gary video, i feel smarter.

Hi Gary. I was trained as an EE, but went to the dark side of sales, so I am only dimly aware of all the subjects you discuss. Thanks for the context and thanks for putting the puzzle together for me.

such a good teacher. Thanks Gary!

Thank you so much! I've read this section in my textbook four times now and just couldn't understand it, but this clears things up so well!

Gary, thanks for making a video on this topic. Great Job.

Finally understood what TLB is. Great video! Keep making quality content!

Concise, clear, informative, and entertaining. Well done!

I got a smile after learning from you in much clear details

actually searched many vedios for this detailed explanation..thanks gary

Thanks again Gary, for a great video. may the L2 TLB be always in your favour!

When ever Gary explains, I understand. He is the only way I am going to get through my systems architecture exam, so thanks!!!

Great. Thank you very much for that. I have found all your Gary Explains videos really good. 👍

I'm stupid but Gary makes me smart.

Greetings world! I'm very new to, Gary's channel & all I can say is, I've been asleep at the wheel for far too long. Sir, this channel is marvelous! From the quality video/audio & editing, to your ability to explain things in a manner with which most anyone can comprehend /completely understand the inner-workings of all this technology that changes every 27 seconds, if you will...😉 I love reading this communities feedback & shared knowledge! Love & Light To You All out there in RU-vid Land and Beyond the world over. Many thanks, Gary for taking what has to be a great amount of time you invest so that, we the viewers, can be educated correctly, efficiently & with absolute ease! 🍀 💜 🎶 👻

Oh my god . Mr. Simps thanks a lot for explains this. When you explained this , it seems so simple. Other people make it sound so tough. I wish I had listen to your lectures earlier. So so good. Thanks you very much from a student trying to explore world of computers.

Best format of this channel

Gary - your ability to explain the complex is unsurpassed.

It wast just the topic for today in OS class, what a coincidence! But, Gary, your explanation was very good, thank you for all this Explaining videos.

i LOVE this series, it brings out my inner nerd.

Garry sir you are really great. I always sleep in my computer class but i like your realxing voice and amazing explaination video.

A gr8 video by Master Gary ! keep em comin 👌

In other words the physical representation of memory and virtual memory is equivalent to how inventory is shipped to a warehouse and memory is the amount of space the warehouse can store of that shipment. Virtual memory is a shipment being processed to go either in its storage location or to be used in either to be once again shipped out or for some function in the warehouse/facility.

OMG THIS WAS FANTASTIC!!! Like I understand, and that's amazing!

This was an amazing explanation, thank you!

Excellent explanation and great teacher

Best explanation i have heard on virtual memory

Great explanation and visuals. Thank you!

Thanks Gary for such a nice explanation.

Great video that brushes all the fundamentals.

Wow very good explanation, Gary is a veryvery good teacher

Thanks, Gary! Great explanation!

hands down the best tutorial on this topic

awesome content Gary!

This was so easy to understand. Thanks!

I'm six years late to the party, but as always there is still so much to learn. Thank you Gary for sending me back from the future, in your video on the demise of 32 bit mode in June 2023. I'm going to look at the one from 2022 now 🙂

GREAT EXPLANATION!!! Thanks a lot

Thank you Gary. It was a great help.

He teaches so nice , better than my teachers

Seriously this cleared all the doubts

thanks! professor Gary! nice job!!

That was a very good overview, thanks! :)

Brilliantly explained

Awesome explanation!

Very interesting and great explanation.

Thank you, Gary

Awesome job Gary 👍

Who are the butttrolls who dislike excellent productions such as this. Wow.

Great video as always ! Please can you explain the effect of screen resolution on performance ? how much does a higher screen resolution effect performance?

Machines have been using virtual memory since the 70's. Gary in his run down of computers did not mention the IBM Mainframes where we had the MVS and VM operating systems which ran very much as Gary explained. There was the additions of the Link Pack Area (or on DOS/VS) machines the SVA (shared Virtual Area) where common routines used by multiple programs would be loaded into memory and shared between all the address spaces, saving real memory. The small operating systems like DOS/VS though only had one address space, so multiple processes would be loaded in to memory in several contiguous regions called partitions. So partition 1 had memory say from 100K to 200K, partition 2 from 200K to 500K, partition 3 500K to600K etc. It was still virtual because address translation between a virtual address and a real address still had to happen. There was not enough memory, so memory was swapped out to disk when it was not required. Often then machines ran with 200K of memory, and ran order processing, payroles, stock processing and even some development all at the same time. This contiguous space for multiple partitions could lead to the two problems which Gary mentioned early on. One program accessing the memory of another, and relative addressing. Each partition was protected from access from another by a protection key. each partition having a different key. A partition when scheduled was allocated the key for its memory. Should it try and access the memory of another partition, then it would fail. The relative addressing was addressed by the loader program .Often a branch address would be loaded form a table to access a routine. If the program was loaded in the partition starting at 200K, or it was loaded in the partition starting at 500K, then this address had to change. That was the job of the loader program, it would correct these addresses as the program was loaded into memory. Yes address spaces as used by MVS and VM were much easier, but they also still had loader programs as you can't predict where routines are loaded into memory in the address space.

I'm a computer science student and Gary has helped me pass in atleast a couple of subjects.

Thank you very much for the video

Did this at Uni last year, It's a good feeling actually understanding what is going on LOL

Really informative video, thanks a lot! :)

Thanks a lot Gary!

This is really a great viedo taht answers my doubts!thanks sir~

excellent discription about virtual and phycial memory..........

man Gary is on a roll to educate the masses lol

under 200 wiew! this is something i know and i work on it everyday, but you still make me learned something new!

you're the man! thank you for a great video

Gary the man !! cheers :)

Excellent explanation!

You're the man, Gary.

Thank you Gary!

Explained beautifully.

That is awesome Gary :)

What an explanation!

Thank you! It is great explanation!

Great explanation!

excellent video!

digging these videos

I think the main use of virtual memory is when there is a need of loading an app that is larger than ur ram then the Virtual Memory concept will be used to load that app by dividing it into some Modules and Only some of the modules of that app will only be loaded into ram.

Awesome video.

I've always wondered how my computers handles this on a constant basis

Cool. I remember when some dumb ass was trying to argue with me, saying android didn't have VM. At first he tried to claim he thought I meant VM was video memory, then tried to say it doesn't have virtual memory either when I explained that was what VM meant. Now I have something to link to explain it to them, if it happens again.

awesome video.Thank you very much

sweet .. very useful thanks Garu

Thank you for this.

Dear Gary, when we have lookup table entities to look into particular Vaddress , why wee need extra MMU translation ? 🤔

Gary.. You Legend!

What happens when some programs are using dynamic memory allocation? How does the MMU can determine how much space does a program need in run time to avioid overwriting? Appreciate any help 😀

this man is awesome!!

Thanks Gary

CONGRATULATIONS!

watching this for my midterm in my operating system course.

What a legend holy moly so good

Just wow! U made it look so simple ,😎

Good morning and congratulations for your precision, unfortunately I didn't understand one thing, but what does offset contain (where on the page we are) can you explain it to me with a more detailed example, thanks in advance

SLAMMED IT! Thank you!!

Gary in AA is like Gandalf in the fellowship of the Ring.

can you do a video on CPU governors and tell which are the best governors