[Info-vax] Request description of UFS for VMS person

[Richard B. Gilbert]

JF Mezei wrote:
> Bob Eager wrote:
> 
>> As you say, unlink just removes a directory entry; all directory entries
>> are 'equal', so when the last one goes, the use count in the inode drops
>> to zero. At that point, the inode is cleared and the file blocks 
>> returned to free space.
>>
>> On MS-DOS, the first byte of the directory entry was set to a special 
>> 'deleted' value, and file blocks were marked as free. Basic, but 
>> sufficient.
> 
> 
> Does this mean that "undelete" is not possible on Unix file systems
> because its logical equivalent to the entry in indexf is actually wiped
> out ?
> 
> With VMS and DOS, it was possible to undelete files because entries were
> just flagged as available and remained until used by another file.

ISTR that UNDELETE IS possible on VMS if you get to it soon enough. 
Once the deleted file's blocks ore the file header are reallocated, 
forget it!

I have an UNDELETE.FOR, a CHECKSUM.MAR, and AAAREADM.1ST for such a 
utility.  I'd be happy to make it available.

Try to remember that it's MUCH better to think BEFORE you DELETE!!
It's also a good idea to make a backup copy on floppy disk or CDROM.
It's amazing how often long forgotten files suddenly reacquire value!