prindle@nadc (08/08/86)
From: prindle@NADC Stupid question of the week: Is it possible to "write" on a diskette inserted into a 1541 when the write enable notch is properly covered? I once tried to bypass the DOS routines and just set the head to "write" mode by going directly to the I/O port; with the write enable covered, it went through all the motions, but did *not* write on the diskette. Thus I've always assumed an electrical interlock is built in. The reason I ask is that a friend had his "1541 physical exam" diskette in the drive (this diskette has *no* notch whatever), had the drive on it's side was not protected), with track 18 totally wiped! He swears there were no magnetized screwdrivers in the vicinity. He subsequently got the drive reasonably aligned without the now-defunct alignment disk and was able to read and write other diskettes normally! So, how could it happen. Any clues? Frank Prindle Prindle@NADC.arpa
rayz@csustan.UUCP (R. L. Zarling) (08/09/86)
In article <3002@caip.RUTGERS.EDU> prindle@nadc writes: > Is it possible to "write" on a diskette inserted into a 1541 when the > write enable notch is properly covered? There is a hardware interlock, that cannot be overridden by software. You cannot write on a write protected disk (unless you modify the drive). However, power glitches *can* write on *any* disk which is left in the drive when power is cycled on or off! This unfortunately often affects track 18, since the head is often positioned there when the power glitch hits. Therefore, *never* have a disk in the drive when you turn the power on or off.