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Negative delta

Posted: Sun Nov 26, 2017 10:25 am
by user1989
Hello,

As part of my evaluation for SmartWim im trying to understand this case:

Here are some points for clarification:

We are using real PC in terms of creating WIM file for the partition C:\ (System OS – Windows 10)


We want to discuss the next scenario



Day 1 – we capture WIM file of partition C: - base WIM
Day…10 –
we performed some changes on this partition and delete a list of files from different paths. In other terms “Day 10” partition has less files comparing to base WIM.
We create .dwm file, that SHOULD reflect the diff between base Day1 and Day10 partition file structure.
We append .dwm file to base WIM (meaning now we have 2 indexes in the single base WIM
Now we are going reimage partition C:\ on the destination PC :
apply Index 1 (base WIM)
apply Index 2 (.dwm) to the same partition


What should we expect in this case on final C:\ partition?





Real situation



Day 1 Base WIM: Day 10

Folder TEST1 Folder TEST1

Files: Files:

1.txt 1.txt

2.txt deleted

3.txt 3.txt





We assume that folder TEST1 on destination C:\ partition will contain all 3 files



1.txt

2.txt

3.txt





Is our assumption correct? Please confirm.

Of course we expect this TEST1 folder after partition reimaging will contain:

1.txt

deleted

3.txt

Re: Negative delta

Posted: Sun Nov 26, 2017 7:04 pm
by synchronicity
Delta WIMs don't work that way; each image still logically contains the full filesystem structure. The "delta" refers to the file *data* being stored elsewhere.

Why create a delta WIM at all if you're just going to export the image back to the base WIM? You could just append the image directly instead.

Re: Negative delta

Posted: Mon Nov 27, 2017 11:26 am
by LeoAO
synchronicity wrote:Delta WIMs don't work that way; each image still logically contains the full filesystem structure. The "delta" refers to the file *data* being stored elsewhere.

Why create a delta WIM at all if you're just going to export the image back to the base WIM? You could just append the image directly instead.
Hi, I'm working on the same project:
The main goal is to deliver "small" update for base WIM file to remote PC (This remote PC stores the base WIM file on separate partition).
We have exact the same base WIM image in-house, that can be applied to real PC. Then this PC will be updated with OS updates and also with custom application and then captured back to WIM file.
We are looking for the correct process of small *delta* preparation.
The delta update should contain OS diff and custom application diff as well. Then the base WIM on remote PC will be updated with *delta* and PC will be re-imaged (with updated WIM file).
Possible we misunderstand the process and difference between *diff* and *delta* and also "how-to..."
Please suggest the correct workflow and technique using WimLib.