Fog Creek Software
Discussion Board

Problems Partitioning the Hard Drive

I am using PartitionMagic to create a partition on my hard drive - IBM ThinkPad R40, Win XP Pro.

Everything was going smoothly till - I received this error message when the computer rebooted:

Error 27 Cannot Lock Drive

I contated the vendor, recently purchased by Symantec, after 48 hours no reply.

The knowledge base was not much help - and Googling did not produce a solution.

Has anyt reader seen this issue before? Can you give me a hand on this? Thanks.

Ringo Starr
Thursday, July 8, 2004

It seems that you'll have to reformat your drive. Let me explain:

A hard drive is just a big magnetic disc (actually several discs). A disc is scanned by a head, which can move from the inside of the disc to the outside. So the data can be stored in circular, concentric tracks. So far you probably knew.

Contrary to what you might think, the computer never really knows the exact physical location where some bit is stored. The disk uses timing to keep the same space between all the bits, and can thus find all the bits, once it has found the location of one. You'll understand that the HD clock must be very precise.

What the BIOS probably means by "locking" the disk, is actually finding the start of a track, i.e. sector 0. This sector is marked with a special code, placed on the disk just like the other bits (actually it is a very long "gap" - a loss of signal, followed by some special signal). It is very important that the HD can find this marker - and in your case it's probably been overwritten.

As I said, you can get the disk to work by reformatting, but you'll lose all your data on the disk. However, some specialized tool could help you out, because probably not all tracks are lost. Use your imagination as to how you can get the tool to run.

Good luck, hope I helped you a bit here.

Thursday, July 8, 2004

See here...

Do not format the drive.

End of message.

Simon Lucy
Thursday, July 8, 2004

Oh, right. I thought the BIOS was displaying the message. In which case the problem would have been worse.
Err, I was just checking if someone else was paying attention here..
:-D sorry.

Thursday, July 8, 2004

*  Recent Topics

*  Fog Creek Home