How come there isn’t any B: Drive on a computer?
You mean, why doesn’t YOUR computer have a B: drive.
Early DOS computer came with two floppy drives, A: and B:. Later on, models with hard drives shipped and they were traditionally assigned to C: and most people skipped the second floppy because they didn’t need it. However, I still know plenty of people with two floppies and a hard drive. Anyway, for a variety of reasons usually assigned the buzzword “legacy compatibility” we are stuck with hard drives starting at C: and floppies at A:
My 8 year old 486 has a B drive. It holds those really huge floppy floppy disk. Remember those?
My Celeron 400 has an a:,b:,c:,d:, and e:. All of them are separate devices. This makes me better than you. 
My a: and b: drives are built into the same unit so as to not take up a lot of room. To tell the truth, I don’t even know if my 5.25" drive even works…I don’t think I’ve ever used it.
askol
The A: drive can also be used as a B: drive. If you only have one floppy drive and you issue the DOS command “copy A:\somefile.txt B:” it will read the file from the floppy currently in the drive, then prompt you to enter a floppy for it to be written to.
It’s long been a goal of mine to have a system that uses every letter of the alphabet. 
BlackKnight, been there, seen it, done it.
[sub]Well, I have had mapped network drives on all the other letters at work when we were really busy. What do you mean that does not count[/sub]
Rick
My 386 has a B: drive for them 5 1/4 floppies, i’ve used it twice ever.
FWIW, my Macs don’t use any silly drive letters at all!
I knew that eventually this question would be asked.
Biggirl wrote:
Yes, those are what we used to call “mini-floppies,” to differentiate them from standard floppy disks, which were eight inches across. At least, I’m assuming that you didn’t have eight-inch floppies in a PC.
Later, around 1983, came micro-floppies, which were 3.5 inches and had a hard plastic shell.
Nope, Microsoft never incorporated support into MS-DOS for anything but 5.25"(DD/HD) and 3.5"(DD/HD/ED) floppy diskette drives.
To answer the OP, B: is reserved by MS-DOS to refer to the second floppy diskette drive. Thanks to backward compatibility, we’re stuck with it. It’s things like this that make me fondly remember AmigaDOS, which had a much more elegant (a la UNIX) system of device handles (DFx: for floppies and DHx: for hard drives). For hard drives, you could even give the device any name you wanted and the OS would use it. This was in addition to the volume names, a feature MS-DOS has, but doesn’t seem to mean anything.
I have a / drive.
Negative. IBM supported 8in floppies with their DisplayWriter migration kit which was targeted at the IBM XT (or was it the AT? It was a long time ago). The DisplayWriter was a dedicated word processor that used 8in disks, and this allowed you to migrate your files to the XT. I recall selling one of these DW kits to John Hughes (you know, the screenwriter).
I’m not saying that some third party never came up with a solution. Hell, get me a 8" floppy drive and interface specifications and I’ll wire it up for you and write a device driver. Microsoft’s MS-DOS, through version 6.22 and including the core of the Windows 9x and NT operating systems, never included native support for those drives. single-sided double-density 8 sector/track 5.25" diskette support (160kB) is as far back as it went. Eight inch drives were already considered obsolete by the time IBM built the first PC and asked Microsoft to write an operating system for it.
You can still hook a second floppy drive into most pc mainboards. So the B: is really a placeholder for that upgrade you never did.
Well, it may be reserved, but it is reassignable; I just successfully remapped my B: drive to a network drive with net use:
c:>net use b: \servername*sharename*
You can do it with Windows explorer as well, I believe.
Umm… IBM is not exactly a “3rd party,” they were the sole source at the time. This 8in drive was official IBM logo product. It was a fairly obscure part and never sold well because nobody ever knew about it (and IBM preferred it that way) but I assure you it had official MS-DOS drivers for 8in drives.
Now if you want to hear about a REALLY obscure floppy format, maybe someday I’ll tell you about the 18in pneumatic-driven floppy drive I used to work with…
my computer has A-H drives becuz its partitioned
Warning: If you are running Windows 2000 do not map drive B: to anything else! If you do, your machine will immediately lock up whenever you log into that user account again. The only solution is to delete the user account and create it again.
Why?