Virtual memory functions like a hidden reserve in your phone, allowing the device to simulate having more memory than it actually does. Think of your phone as a magician with an array of hats in his closet. Virtual memory is the unseen hat that materializes out of thin air whenever it is needed.
Everything from the cheapest to the costliest smartphone uses this trick. So don’t fear those high-sounding terms like “Virtual RAM”. It is not some special feature; it’s just how your phone work behind the scenes.
A brief history
The concept of virtual memory was introduced in 1959 at the University of Manchester computer lab as part of a joint project with Ferranti Computers and Plessey. It was integral to the famous Atlas Computer system, which was the fastest computer in the world at the time, mainly due to the novel memory management system it developed.
Imagine: Back then, computers were really inefficient assistants, easily distracted. To write even an interesting program, programmers had to give a computer an awful lot of extra information about where it was supposed to find and store other information. It was painful, like trying to juggle multiple tasks at once while also being the traffic cop for your own data.
Virtual memory changed everything. Now the data shuffling, which often takes most of our time, is taken care of by the super-efficient assistant behind our back. Programmers do not have to think about where everything lives. It is like an endless work space when in reality there is only a little less actual space.
A similar system is used by your Android phone, too. It has a built-in manager, referred to as a kernel, that takes care of all the complex issues so you can go ahead and use your phone without having to think about how everything works.
Virtual Memory: Your Phone’s Personal Librarian
Imagine that your phone is the super-duper busy librarian. It has a small desk-the RAM where it keeps few books data open for quick references. But that’s not all; there’s a humongous library-laden with countless books data- waiting to be used.
Just as you can only focus on a few books at a time, your phone can only remember so many pieces of data in its fast-access workspace called RAM. When it needs something new, it is like asking the librarian to find a specific book and bring it to your desk. For example, the librarian-your phone’s system-knows where everything is and can swap out books as needed, so you don’t need to run out of space at your desk to continue researching.
Life Before Virtual Memory: The Bookworm Struggle
Imagine a world where librarians don’t exist. So whenever you need a particular book, you must stand up from your desk, go through the seemingly infinite aisle of shelves, and get that particular book back to your study area.
And if the drawer of your desk is full, you will have to take decisions on which books to put back in the shelf, regardless if not finished reading them. So it was almost a consistent battle in managing your workspace; this slowed down your research process appreciably.
Virtual Memory: Your Personal Librarian on Demand
You could have your own personal librarian and a dedicated shelf next to your desk. When you needed that one book, your librarian would have it for you straight away. And if your desk became cramped, they’d temporarily stash the least-used book from your shelf in order to make room for the new book.
Virtual memory is magic that makes room for the computer to store its data. Rather than trying to remember everything in its head, your computer functions as the world’s most efficient librarian: it keeps things straight on the sly while you work.
Virtual Memory: The Magic of Location Independence
Imagine how virtual memory works by thinking about addresses. Traditionally, an address was like a specific spot on your desk. You could only put one book there at a time. Once your desk was full, you were out of luck.
But virtual memory allows you to simply treat all those addresses as magic portals. You can give any book any address on your desk, though that book is actually located somewhere else in the library. Imagine having a personal librarian who knows exactly where each of your books is and gets it to you in less than a split instant, regardless of where on the shelves it may be.
This genius invention changed the way computers handle information in such a way that, seemingly, we have infinite working space.
Virtual Memory: Android’s Super-Smart Librarian
An Android’s virtual memory is simply like having a super intelligent librarian for your smartphone. After all, it is a complex system that lets your apps imagine that they have vast space to work in when the phone has technically a much limited amount of memory which is limited in physical memory.
Imagine your phone’s memory as a small desk. Virtual memory is therefore having a vast library and librarian who can probably quickly find any book you require to place on your desk. So, in this regard, your apps can just continue to operate and not run out of space.
Android applies this trick of keeping your apps apart and safe. It’s somewhat like having separate rooms for different apps so they cannot mess up each other’s stuff. Your phone will be smoothened off, and developers can make better apps without worrying about memory problems.
Virtual Memory: Behind the Scenes
Paging: Divide and Conquer
Think of your phone’s memory as being a really long bookshelf. Virtual pages are the sections of a book. The page table is an incredibly detailed map that shows your phone where to find each section on the bookshelf (your phone’s RAM). When you’re reading, the MMU finds where the piece is located on the bookshelf for your phone.
Swapping: Making Room
There’s a sneaky way Android uses to make the most of how much you can fit onto your phone: zRAM. This is like more tightly packed books into your bookcase. That means the phone will run better, but it takes you longer to read a packed book.
Low Memory Killer: Cleaning the Floors of the Phone
In case memory gets low, there is a special helper on the phone known as the Low Memory Killer. This helper closes apps not necessary for memory space used by apps being used. It’s like cleaning up your desk so you can accommodate important documents better.
Virtual memory: the unsung hero of your phone
Save your apps from themselves
Virtual memory is your personal private space for any number of apps. A virtual memory will ensure that any app running in memory won’t conflict with others. That way, you basically have roommates who respect each other’s space. Thanks to virtual memory, you can save privacy to keep your phone safe.
More Apps and Less Stress
Imagine the cache of your phone as a small table. Virtual memory is comparable to the magic storage unit which produces everything quickly. This means that a phone can run many applications at the same time without delaying it. It is just like being served by the most efficient waiter who knows where everything is located.
Virtual Memory: The Price of Convenience
Virtual memory is great but not perfect.
Think of your phone as a busy restaurant. Occasionally, the waiter (your phone’s system) won’t have the precise dish (data) available, so the waiter must go off to the kitchen (storage) to retrieve it. This is what we refer to as a page fault and causes a short delay.
The phone also saves disk space by an ingenious trick called zRAM. Just like putting loads of information in a small bag, it will be cramped in there, but that only takes a little more time to open the bag.
Keeping your apps running, your phone has a manager who sometimes closes them out to free up space. Not particularly fun when you end up switching back to the same app that had a delay in reopening.
That’s why your phone is always learning and adjusting. It’s trying to figure out the best way to use its memory based on what you’re doing. This is adaptive memory management.
SSDs: Fast, But Not There Yet
You could ask if super-speed SSDs made virtual memory obsolete. The short answer is no. While still much faster than older hard drives, they are much slower than your cell phone’s main memory.
Think of it this way: your desk is the primary memory on your smartphone, and the books you are currently reading sit on your desk. The SSD is like a super-fast librarian who can dash into the shelves and grab a book really, really fast. Now that the librarian is moving at such a lightning speed, I’d still prefer grabbing a book already on my desk rather than waiting for a book to return from the shelf.
Thus, virtual memory is still essential to let your phone run fine. It is actually the mechanism whereby your phone decides what to keep on your desk or main memory and what to send the librarian or SSD to fetch.
Leave Virtual Memory alone!
You probably know someone is talking about how turning off virtual memory can speed up your Android. Don’t believe it! Generally, there is nothing bad in keeping it turned on. Virtual memory works as a clever assistant for your phone.
This technology has been here for ages and constantly bettering itself. It is meant to make your phone faster and safer and easier for app developers, so unless you have a specific problem with your phone’s virtual memory, just let it do its job.
It is the unsung hero of your smartphone. The device is working hard behind the scenes to give you the best experience possible.
