Eraser wipes what: Free Space, Unused Space or File Slack?


New Member
I am not sure what I am actually wiping on a hard drive when I want to remove deleted files? :) Is it Free Space, Unused Space, File Slack, Swap File or what? I’m using WinXP SP3. I’ve used DiskDigger (Freeware and it shows me what is still on my hardrive after a wipe). I’ve used BCWipe and it doesn’t seem to be able to wipe my hardrive. I just downloaded Eraser version Eraser and version Eraser 5.8.8. You said that you use version 5 because it is more stable – does it mater which one? I’m hoping that it truly will work to remove deleted files.
The file slack is that portion of the file that got allocated, but never actually used because of cluster sizing... so you might have allocated 512 bytes (physical size) for some file X, but only have used 490 bytes (logical size). The term "slack" refers to difference between a file's physical size and logical size so the 22 unused bytes constitute the slack (just so we agree on terminology). In the grand scheme of things, erasing the file slack (even if you CAN), doesn't "buy" you much.

So as for your question, I guess your answer depends on what you want, but TYPICALLY you would erase free space (wipes out data stored in files you've "deleted from disk" by writing some pattern of bits to those locations) though you might also want to erase the pagefile (erases the contest of the virtual memory that exists in the pagefile( s ) on disk) on shutdown. The older version of Eraser provided the ability to define a blank erase pattern which can prove VERY helpful when dealing with virtual machines. If you overwrite the pagefile with 0's for instance... that compresses very nicely when you Zip the virtual machine's virtual hard drive.

Unfortunately it LOOKS like the ability to define a blank pattern doesn't exist in 6.x :cry:

CGOSenseiC said:
Unfortunately it LOOKS like the ability to define a blank pattern doesn't exist in 6.x :cry:
I believe it does, and have responded accordingly to the separate post on this in another thread.

I guess I should clarify terminology here:
  • Free space = unused space = space not marked as allocated on disk
  • File slack = cluster tips = cluster size - logical size (*in post two)
Hope this helps. We've been using our own terminology for a... very long time.