Fact Checked

What is Flash Memory?

R. Kayne
R. Kayne

Flash memory refers to a particular type of electronically erasable programmable read-only memory (EEPROM). It is a computer memory chip that maintains stored information without requiring a power source. It is often used in portable electronics, such as digital music devices, smartphones and digital cameras, as well as in removable storage devices. This technology also is useful for computer basic input/output systems (BIOS), Personal Computer Memory Card International Association (PCMCIA) cards, modems and video game cards.

Speed Advantage

Two flash memory chips.
Two flash memory chips.

Flash memory differs from regular EEPROM in that EEPROM erases its content one byte at a time. This makes it slow to update. Flash memory can erase its data in entire blocks, making it a preferable technology for applications that require frequent updating of large amounts of data, as in the case of a memory stick for a digital electronic device.

Inside the flash chip, information is stored in cells. A floating-gate transistor protects the data that is written in each cell. Tunneling electrons pass through a low conductive material to change the electronic charge of the gate "in a flash," clearing the cell of its contents so that it can be rewritten. This is how flash memory gets its name.

Nonvolatile and Silent

Many phones use flash memory cards.
Many phones use flash memory cards.

Flash memory used as a hard drive to store data on a computer has many advantages over a traditional hard drive. It is nonvolatile and in a solid state, which means that there are no moving parts. It also is silent, much smaller than a traditional hard drive and highly portable, with a much faster access time. A traditional hard drive has the advantage over a flash drive in price and capacity. Hard drives are many times larger for a price that is cheaper per megabyte of memory.

Advances in Technology

Flash memory cards are often used with digital cameras.
Flash memory cards are often used with digital cameras.

The price of flash memory has continued to drop, and its capacity has continued to rise. This makes it a prime candidate for an ever-broadening set of applications. It is especially popular in portable electronics. A memory stick can store pictures in a digital camera, for example, then be removed and inserted into a computer, where the pictures can be accessed.

Flash memory is not the same as flash random access memory (RAM). Flash RAM, like any type of RAM in a computer, requires a continual power source to maintain its contents. When the power is lost or turned off, the flash RAM is wiped away. Flash memory, on the other hand, will remain on the chip or memory stick even when it is not connected to a power source.

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Discussion Comments

It is amazing how fast flash memory has taken over everything. It's understandable, considering it is a much better alternative to moving drives in almost every way. If it weren't for SD flash memory and the other things, we still wouldn't have digital cameras. Flash memory prices have been steadily going down, so I'd say it's only a matter of time until we stop using moving drives.

I remember many years ago buying my first USB flash drive. They were still a relatively new replacement to floppy drives at that point. I got one with 256 MB of memory for about 30 dollars. That seems crazy considering I just bought a flash drive with 64 GB of memory for less than that. That is a 250-fold increase in storage space for the same price just about 10 years apart from each other.


Interesting. I always wondered why flash memory had its name. I knew it was supposed to be faster than a moving hard drive, but I didn't know that it stored everything in blocks. I remember that for one of my old video game systems the memory cards stored things in blocks. I bet it was using flash memory.

I think almost all MP3 players now use flash memory. I had one of the first ones, and it had a moving disk inside of it. I'm glad companies finally switched over to flash, though. Since I listened to music so much, the disk finally wore out right as the warranty expired. Besides that, the songs could skip just like a CD player, because jostling the device would cause the disk to misread. It took more time to load songs onto that MP3 player, too.


@JimmyT - Apple now has the MacBook Air, which does use flash memory as the main hard drive. It is the first non-notebook laptop I have seen that uses only flash memory.

That being said, it has the same problems that have been mentioned. For the same price as a regular MacBook, you get a fraction of the hard drive space. Of the Airs I looked at, you usually just get 1/3 of the storage space for an equal price. It's Apple, though, so people will buy it.

I don't pay a lot of attention to computers, so maybe there are some Windows machines that are coming out with SSD for the main memory. I would be interested to know how they compare in price to a HDD.


@anon125909 - Yes, SSDs can be very large and do a lot of the things you said, but to my knowledge there are very few computers that actually use them as the main drive that is running the operating system. I believe that is the problem Fiorite is talking about.

I'm sure there are a few exceptions, but every desktop computer I have ever seen and most laptops all have hard disk drives for the reasons the article mentioned - they are cheaper and larger.

I don't know about Macs, but you also can't install a Windows operating system on an external drive. I have tried it before, and it won't work without altering the motherboard settings.


@Fiorite - easily removable ssds? that's the same thing as flash drives (usb drives, sd cards, memory sticks, etc), right? you can encrypt them, partition them, install operating systems on them, use them as replacement/extension for RAM (inefficient though) etc., and they're not as big as ssd which purpose is to replace hdd in computers (or other types of mass nonvolatile memory that needn't be transportable). and if mass storage is what you need, there are already flash drives of huge sizes (256GB is the biggest I've seen thus far (nov 2010)).

what world are you living in? (not to be rude, I think flash drives are more known than ssds).


I wouldn't be surprised if in the future you see personal computers with easily removable solid state drives. This would increase security because someone could store encrypted sensitive information on a solid-state drive, and transfer it back and forth between work desktops, portable devices and laptops.

I am a student and I have been considering a laptop with a solid-state drive because it will allow my computer to take the abuse of being in a backpack. I also would not have to worry about losing information if I dropped my computer, and the weight savings would be nice too.


@ Crl138- This is a common problem many people encounter. The solution is to go to your camera menu, open the options tab, open general and change your storage settings.

If you cannot access this sequence of menus, you may need to update your firmware. Upgrading to windows mobile 6.1 or better should take care of all the issues with your camera application.

You should be able to use your flash drive without any problems. Just remember you will have to direct each application to store information on the flash drive.


i have bought a microSD card for my blackjackII. i put it in, but for some reason, it's still not letting me store pics on it, or even take more pics.. (since my phone has 150+pics) do i need to do something else?? please help, no one can...

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    • Two flash memory chips.
      By: Scanrail
      Two flash memory chips.
    • Many phones use flash memory cards.
      By: Xuejun li
      Many phones use flash memory cards.
    • Flash memory cards are often used with digital cameras.
      By: Deyan Georgiev
      Flash memory cards are often used with digital cameras.