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Why do we see a:\> even when booting from CD.

By ashwa ยท 16 replies
Jan 8, 2008
  1. while we boot from HD we see C promt.
    while booting from floppy we see A prompt &
    when booting from bootable CD we still see A prompt...why so?

    i have 4 partitions labelled as C,D,E,F & G(dvd rw). when trying to change driver letter of any of the drive by going to administrative tools & then to computer management, then using disk management i never see letters 'A' & 'B', why so?
  2. raybay

    raybay TS Evangelist Posts: 7,241   +10

    Go into your BIOS, which you can do at startup by pressing the key that is flashed briefly on the screen. Usually <ESC>, <F1>, <F2>, <F10>, <F11>, F12>, or <DEL>
    Then edit your boot order in a way that suits you.
  3. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    There are two ways of booting from CDs. Native CD booting and floppy emulation. If your CD was made bootable using floppy emulation, then you will boot from a virtual floppy drive that appears as A:

    A and B are not visible in disk management, because these drive letters are reserved for floppy drives.
  4. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    how will that help in understanding the answer to my que? i dont wanna change the boot order, even if i choose dvd drive as my 1st booting device n then boot from bootable CD then also it shows A:\> & thats what i want to know,y?

    can u pls tell how a CD can be made bootable using floppy emulation? i have only made bootable floppy disk using win98 & use the default windows xp cd to boot/reinstall.
  5. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    Your CD burning program should have an option to write a bootable CD. And you should have an option there to read in a (hopefully bootable) floppy.
  6. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    will try it
  7. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    but why to have an A promt when there is no need of it? as pc's now a days dont carry floppy drive
  8. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    Really? You have seen every single PC in existence? :p

    Anyway, you probably misunderstand the A: prompt. You get the prompt in a program, namely DOS. When DOS was created, floppies were the only medium used on PCs. And today, floppies (virtual or real) are usually the only medium where DOS is run from. Removing floppy support from DOS would be something like removing CD-ROM support from Windows assuming that everyone uses flash drives or DVDs nowadays.
  9. MetalX

    MetalX TechSpot Chancellor Posts: 1,388

    They really should rewrite Windows so the A:/ drive and the B:/ drive are no longer reserved for floppies... I mean, nobody uses those things anymore. You can buy flash drives that hold about 3000x the capacity of a floppy, and they're smaller. I can see if they have it there for "virtual floppies" as you say, but why not just remove the concept entirely, and allow for 2 more drives/partitions?
  10. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    hmm its clearing up a bit...yah, earlier OS/bootdisk use to come in floppie(if i am not wrong)...plsss ans these

    so DOS cant run without a floppy support, is it?every time we run DOS/command promt we are using virtual floppy?

    cant run DOS from CD as such, we use the virtual floppies?

    every pc has a virtual floppy? are these virtual floppies in BIOS?

    i dont have a floppy drive now so whn i run DOS from my winxp i m using virtual floppy? while booting from bootable CD its actually the virtual floppy it gets booted from right?
  11. DeepMartin

    DeepMartin TS Rookie Posts: 54

    I kind of agree with you

    I took out mine since i though it might help with less power consumption and better airflow/less cables but it didn't make a HUGE difference just made "my computer" folder load a tiny faster and less cables to deal with so i am happy about giving up on it

    but everyone including me relates A: or B: to floopy and hey theres no need to rewrite everything and leave people that use it with the hassle of adapting to a new letter when you still got D to Z to fill up and those are a lot of pendrives lol
  12. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    If you do not have a floppy drive, then you should be able to assign A and B to drives. At least I can in Windows XP and 2003..

    It would not be good idea to remove the A: B: reservation though.. Imagine a program that assumes A: is always the floppy drive. And now that program wants to format the floppy..
  13. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    well i tried changing the drive letter but it doesnt show A & B letters while renaming the drives.

    can u pls ans post #10 if i aint eating too much of ur brain :).

  14. Samstoned

    Samstoned TechSpot Paladin Posts: 1,018

    now you gone and done it:chef:
  15. kimsland

    kimsland Ex-TechSpotter Posts: 14,524

    I love BootCd's, I've been making them for years now
    A long time ago, I worked out how to edit everything in bootable CD's
    But I am now defeated by Linux bootable CD's, which are far superior
  16. ashwa

    ashwa TS Rookie Topic Starter Posts: 56

    tnx a lot kimsland for the ans u provided...can u pls provide me with links that will help me in making bootable CD's so that i can clear up my doubts by making some of them myself.

    i m not of expert level. just a rookie trying to increase my knowledge so pls provide site links that will be easy for me to understand.

    regards & tnx all :)
  17. kimsland

    kimsland Ex-TechSpotter Posts: 14,524

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