[h-e-w] About backup-enable-predicate

[Ismael Valladolid Torres]

When I edit files in my USB disk, I don't want backups to be
created. This snippet works lovely on my Linux box:

(defun my-backup-enable-predicate (filename)
    (not (string= "/media/usbdisk" (substring filename 0 14))))
(setq backup-enable-predicate 'my-backup-enable-predicate)

However, at work, using W2K, the USB disk gets mounted as E:. Then
I've tried this but doesn't work!

(defun my-backup-enable-predicate (filename)
    (not (string= "e:" (substring filename 0 2))))
(setq backup-enable-predicate 'my-backup-enable-predicate)

Any ideas, comments or suggestions are welcome!

Cordially, Ismael