Why Are The A & B Drives Not Used By Windows?

This post may be a bit more nostalgic than useful, but it does answer a question that I’m sure that many new computer users have wondered at one time or another.  When you buy a brand new PC, you’ll notice that C:, your primary disk drive, is always the first letter listed under your Computer.  Your DVD/Blu-Ray is probably next, as D:, and then following that are any peripherals you add such as external drives or memory slots.  Yet, the letters A: and B: are never used.  Let’s look at why!

What was in the A & B drive and what happened to them?

Some computers may still have these, but back in the day, the A: and B: drive were reserved for use as Floppy Disk Drives.  The reason you might not have heard of these drives is because all big computer fabricators generally stopped including them on personal computers in 2003, with the earlier being Apple who began disregarding the drives in 1998 on their iMac computers.

It was common to have two drives, hence why A & B are reserved.  This is because of drive incompatibility, there wasn’t a set standard at the time and so you had to be prepared to read media that was formatted differently.

different floppy drive sizes

Why did we use floppy drives?

Well, floppy drives are necessary to read our floppy disks of course!  Before Blu-Ray there was the DVD (Digital Video Disc) there before that there was the CD (Compact Disc).  As you know as each new media format was released, we are able to fit more information onto each one.  The floppy disk is the predecessor of the CD, and it sure didn’t hold much.  Floppy drives started out large in size as well, the first ones available in 1971 were a whopping 8 inches in diameter with a total storage capacity of 175KB.  To put that into perspective, 175KB is about 10 seconds of your favorite MP3 song.  Yeah not much, but at the time it was a big deal! As years passed technology improved and the standard moved down 5¼-inch size disks that could hold more especially if you notched the side of the disk so you could flip it over!

Thanks mostly to IBM, by the early 90’s the new standard became 3½-inch disks that could hold a sizeable 1.44MB!  But, by the time the 90’s rolled around the CD was already gaining popularity in the music industry, and computer geeks caught on and started using it to store data as well.  By 1996 CDs completely took over and the only people still using floppys were power users and system admins (however I still have good ole Ghost on mine!).

floppy disk example image

If nobody uses floppy drives anymore, why not use A: and B: drives again?

Even though few people still even have floppy drives, C:\ has always been the traditional installation drive of Windows.  Having these drives open also provides support for users that might still need to make use of floppy drives for managing older systems or drivers.  But, if you’re alphabetically agitated by this, Microsoft made it so that you can remap your drives and make A: your new C:.  Just follow our groovy tutorial for changing drive letters in Windows 7 and Vista.

So, now you know your A:b:c:’s…  Wow writing all of this sure makes me feel like an old geek.  Anyone else feel the same?

Editors Note: Yes… especially since I have about 200 floppy disks sitting right behind me which I refuse to throw away despite my wife always trying to slip them into the trash!!!




  1. vadim

    January 25, 2011 at 8:40 am

    So what your saying is if you have floppies laying around, your an old man! LOL – Yup, that’s me! (and you better not try to take them away from me!). 1.44MB baby yeah!

  2. Dyanne @TravelnLass

    January 25, 2011 at 9:32 am

    And uh, some of us even remember PUNCH CARDS! Thanks for a fun walk down digital-memory-lane.

    • MrGroove

      January 27, 2011 at 9:21 am

      @Dyanne – hehehe yeah…. We left out the Punch Cards! I have to admit those were JUST before my time. Just barely tho…. ;)

  3. Sid@Malaysia

    January 26, 2011 at 9:57 am

    Man, I still remember I liked to slide the floppy disk’s cover that keeps the disk from dust, and touch the disk with my bare fingers, then release the cover back to its spring!

    Oh how my first experience of 1996 has passed.

    Thanks dude for the reminiscence! :)

    • Steve Krause

      July 7, 2012 at 8:24 pm

      You took me back @93526686d6090ee9594201b01cd20968:disqus :) It was a good ride!

  4. Jeffrey Wisniewski

    January 26, 2011 at 12:30 pm

    I even remember buying in bulk to try and save a few pennies per disk when I was buying 500 discs at a time.

    – jeffsw3

  5. Steven Perillo

    July 6, 2012 at 12:47 am

    you forgot zip disks, and tape decks, and flash media will surpass optic media soon

    • Steve Krause

      July 7, 2012 at 8:25 pm

      Yup… that’s going way way back machine there!

  6. Bogdan Bele

    October 16, 2012 at 9:23 am

    Just ran into this article. Great trip down memory lane.
    The funny thing is that I found a floppy disk yesterday, too, and I hadn’t seen one in quite some time. Man, those wer great times. I would zip a game to multiple disks and at some point I started using a zip drive and that could work with really large stuff (I mean, 100 MB…). Anyone remember those?

    • Steve Krause

      October 16, 2012 at 10:13 am

      100MB is Huge!!!!!

      Wow, amazing how time flies and tech changes. Feels like we are on the cusp of flipping from gigs to terabytes. It’s almost here!

  7. Mark Hike

    August 7, 2017 at 6:24 pm

    This article is not accurate. CDs didn’t replace floppies. CDs are read-only and CD rewritables never got popular. It was the USB thumb drives which finally killed the floppies.

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