ADSM-L

Re: Mac PowerPC native mode executable.

1994-06-27 11:12:00
Subject: Re: Mac PowerPC native mode executable.
From: Ken Rosenberry 814 865 4763 <HKR AT PSUVM.PSU DOT EDU>
Date: Mon, 27 Jun 1994 11:12:00 EDT
In regards to Keith Crabb's message which contained:

>Yeah, major bummer, just found out about that.  I've been told that the
>Mac actually touches that file each time the SoftWindows stuff runs.
>I can't verify that until next week though, a co-workers supposed to
>have one delivered later this week.  That would be bad, real bad.  I'm
>not wild about backing up that 61M Mac file (that's apparently the
>default size for the SoftWindows Harddisk), it's really just an image
>backup at that point.  Anyone tried renaming it and doing a restore to
>see if SoftWindows complains?  I don't think it would but.....

About the only thing that can mess up a file which is restored by ADSM
is the 'file id' number of a file or the 'directory id' of a folder.
These id numbers (assigned from the same pool of numbers) are unique
for every file and folder on each disk.  Id numbers are not reused
even if the file or folder are deleted from the hard disk.  Also, id
numbers don't change even if the file/folder is moved or renamed.

Id numbers are assigned whenever a file (or folder) is created.  Thus
files and folders restored from backup will have a different id number
from the time the file existed on hard disk.

Some applications (mostly games, but a few real apps like Mathematica
I seem to recall) use the file number to detect if the file has been
recently copied to a new hard disk.  If the file id number changes,
the application may request verification that the user really owns the
program.  Some applications will ask you to enter you serial number
again; other applications may ask you to insert your original disk.
(What a pain that is when you have a duo270c and no floppy drive!!!)

So, if SoftWindows is too clever and keeps the file id number of it's
virtual hard drives, and the files are restored, it could cause
problems.  An easy way to test that without ADSM would be to copy the
hard drive image file to another volume, delete the original, copy the
image back to it's original spot and see what happens.

I would doubt that SoftWindows would do any such thing with the file
id numbers.  If it did, you wouldn't be able to copy the SoftWindows
folder from volume to volume.

- - - -

Some programs use folder ID numbers to find files.  If you restore the
folders containing certain files, you may have to navigate a standard
file dialog box in order to tell the application where some file is
kept.  Perhaps a preference file or a helper application, etc.
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