Difference between how MOV and MP4 files are treated in SharePoint Online

For some reason MOVs and MP4s exhibit different behavior in SharePoint Online. In the image below I have an MOV which displays correctly and runs when clicked, but the MP4 presents a folder containing the MP4, the thumbnail, and an “Other” file.

Additionally, notice the filtering option doesn’t present MP4. Any thoughts here?

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What is the difference between data owner , data custodian and system owner

I just started studying up for the CISSP and am having trouble understanding few concepts.

  • Data Owner
  • Data custodian
  • System owner

Somewhere I read

The data owner (information owner) is usually a member of management who is in charge of a specific business unit, and who is ultimately responsible for the protection and use of a specific subset of information.

The data custodian (information custodian) is responsible for maintaining and protecting the data

But in practical world, what exactly is the boundary for these roles? Both seems to be protecting data.

Any real-time example helps.

What is the difference between “drop_caches” and “blockdev –flushbufs”?

As the title says, I am confused about “echo # > /proc/sys/vm/drop_caches” and blockdev –flushbufs.


According to OSSTEP, If the target inodes are not cached in memory, disk IO should be occur to read the inode, which will make a dentry data structure on memory.

To my knowledge, echo 3 > /proc/sys/vm/drop_caches is to drop(clear) page cahche, inodes and dentry.

I have experimented with blktrace to figure out whether disk io is really occurring to read the inode.

1) echo 3 > /proc/sys/vm/drop_caches

> 259,0   38        1     0.000000000 40641  Q   R 109314048 + 32 [cat] > 259,0   38        2     0.000004096 40641  G   R 109314048 + 32 [cat] > 259,0   38        3     0.000027108 40641 UT   N [cat] 1 > 259,0   38        4     0.000027862 40641  I   R 109314048 + 32 [cat] > 259,0   38        5     0.000036393 40641  D   R 109314048 + 32 [cat] > 259,0   38        6     0.006268251     0  C   R 109314048 + 32 [0] 

However, there is no disk io to read inode. I can only see the disk io to read 16KB data block.

2) echo 3 > /proc/sys/vm/drop_caches and blockdev --flushbufs /dev/nvme0n1

259,0    1        1     0.000000000   325  Q  RM 74232 + 8 [cat]      259,0    1        2     0.000004854   325  G  RM 74232 + 8 [cat] 259,0    1        3     0.000026263   325  D  RM 74232 + 8 [cat] 259,0    1        4     0.006292470     0  C  RM 74232 + 8 [0] 259,0    1        5     0.006382162   325  Q  RM 109052160 + 8 [cat] 259,0    1        6     0.006385621   325  G  RM 109052160 + 8 [cat] 259,0    1        7     0.006393322   325  D  RM 109052160 + 8 [cat] 259,0    1        8     0.006455750     0  C  RM 109052160 + 8 [0] 259,0    1        9     0.006511245   325  Q  RM 109117696 + 8 [cat] 259,0    1       10     0.006512342   325  G  RM 109117696 + 8 [cat] 259,0    1       11     0.006514627   325  D  RM 109117696 + 8 [cat] 259,0    1       12     0.006591933     0  C  RM 109117696 + 8 [0] 259,0    1       13     0.006624544   325  Q  RM 109117704 + 8 [cat] 259,0    1       14     0.006625538   325  G  RM 109117704 + 8 [cat] 259,0    1       15     0.006627567   325  D  RM 109117704 + 8 [cat] 259,0    1       16     0.006688973     0  C  RM 109117704 + 8 [0] 259,0    1       17     0.006764838   325  Q   R 109314048 + 32 [cat] 259,0    1       18     0.006766035   325  G   R 109314048 + 32 [cat] 259,0    1       19     0.006768078   325 UT   N [cat] 1 259,0    1       20     0.006768755   325  I   R 109314048 + 32 [cat] 259,0    1       21     0.006773426   325  D   R 109314048 + 32 [cat] 259,0    1       22     0.006854480     0  C   R 109314048 + 32 [0] 

I found block access (+8(512*8=4KB)) to read inode.

A quick look at how blockdev –flushbufs works in the kernel code shows that it clears the superblock.

Why doesn’t disk io to read inodes with drop_cache alone?

The ULK book says that inodes or superblocks are cached in buffer-cache. The book ULK says that inodes and superblocks are cached in buffer-cache. Is this the reason for this?

Thank you

What is the difference between nearest and cheapest insertion algorithms for a Traveling salesman problem?

I know that in the cheapest insertion algorithm we include the node which is not in the “base group” that has smaller cost given all possible combinations, and for the nearest we include the node with smaller cost. So, do they differ only in how combinations are made?

For example, I have the following weighted matrix graph:

     2  13  14  17  20 2  0.0 Inf Inf 1.9 1.7 13 Inf 0.0 7.3 7.4 7.2 14 Inf 7.3 0.0 7.7 7.8 17 1.9 7.4 7.7 0.0 9.2 20 1.7 7.2 7.8 9.2 0.0 

If I start from node 2 from each method:


1) 2-20-2

2.1) 2-17-20-2 = 12,8

2.2) 2-17-20-2 = 12,8 *Choosen

3.1) 2-13-20-17-2 = Inf

3.2) 2-20-13-17-2 = 18,2 *Choosen

3.3) 2-20-17-13-2 = Inf

4.1) 2-14-20-13-17-2 = Inf

4.2) 2-20-14-13-17-2 = 26,1

4.3) 2-20-13-14-17-2 = 25,8 *Choosen one

4.4) 2-20-13-17-14-2 = Inf


1) 2-20-2 2.1.a) 2-13-20-2 = Inf

2.1.b) 2-20-13-2 = Inf

2.2.a) 2-14-20-2 = Inf

2.2.b) 2-20-14-2 = Inf

2.3.a) 2-17-20-2 = 12,8

2.3.b) 2-20-17-2 = 12,8

So, with the cheapest approach, do I explicitly make all combinations?

What is the difference between a god and a primordial?

Out-of-universe, I gather that the primordials were introduced to the FR in 4e, and the elemental lords – Akadi, Grumbar, Kossuth and Istishia – were retconned as primordials. Information on the primordials is fairly scant in the core 5e rules, and my other sources are mostly 2e (before they were added) so I’m trying to work out how they fit in.

In-universe, as far as I can tell the primordials predated the formation of Realmspace by Ao and the spontaneous generation of the first gods, Shar and Selune. The gods and primordials have subsequently been at war (the Dawn War).

It therefore sounds like primordials and gods are mutually exclusive definitions. However, I noticed Asgorath/Io is variously referred to as a god (of dragons) and a primordial. In FR the dragons were created by the primordials. Does this mean many/most/all dragon gods are also primordials, as aspects/fragments of Io? Can a primordial also be (or somehow become) a god?

Do primordials need, desire or benefit from followers? If the primordials predated the gods, presumably they don’t need them – but then if I remember correctly neither did the gods until after the Time of Troubles. Do surviving primordials have significant religions associated with them, either in Abeir or in Toril?

Do primordials grant spells in the same way as gods? Can they be warlock patrons?

Is there any obvious difference in the portfolios of primordials versus gods? I would have assumed that since they predate mortals they tend to represent more fundamental forces (like the elements) rather than human concepts like law, love, luck, agriculture. Is this assumption correct? A fair few gods seems to have portfolios that superficially seem more appropriate to primordials – Auril, for example.

In short, what is the difference between a god and a primordial? Are they fundamentally the same (just different lineages) or are there fundamental differences?

I found this related question about gods versus ‘non-god powers’, but neither the question nor the answer mentions primordials, which are the core of my question.

I also found this fantastically detailed post on Candlekeep which defines and differentiates primordials, deities, vestiges, cosmic entities and sentient artifacts with respect to most of the aspects I asked about above (and some that didn’t even occur to me, like which can create avatars), but it doesn’t cite any sources and is pre-5e (I’m guessing 4e).

Fundamental difference in security research in Cloud platform VM and normal machine

I am trying to study the effects of various network based attacks in an Openstack Cloud environment that I have setup with few machines. However, what would be the fundamental difference between a VM created using Openstack and a normal VM created using a single machine?

Both of the VMs are ought to have the same specs. The major difference that I see is that the attacks done on VM in Openstack would take a different network route (due to distributed resource sharing) as compared to direct attack on a VM on a single physical machine but wouldn’t the effect on both the targets be same?

Rewrite rule to load images from production makes no difference

I’m trying to adapt the rewrite rule given in Develop Locally, Use Images from Production to do the very same thing on my local dev site (which runs on XAMPP).

This is how the development site’s .htaccess looks, with the snippet added towards the end of it (URL replaced with example.com equivalent, obviously):

<IfModule mod_php.c> php_value upload_max_filesize 64M php_value post_max_size 64M php_value max_execution_time 300 php_value max_input_time 300 </IfModule>  #START WORDPRESS  <IfModule mod_rewrite.c> RewriteEngine On RewriteBase /wordpress/  # Redirect About and Library to first sub page  RewriteRule ^about/?$   /wordpress/about/history/ [L,NC,R=301] RewriteRule ^the-library/?$   /wordpress/the-library/gallery/ [L,NC,R=301]  RewriteRule ^index\.php$   - [L]  RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . index.php [L]  # If images not found on development site, load from production  RewriteCond %{REQUEST_URI} ^/wp-content/uploads/[^\/]*/.*$   RewriteRule ^(.*)$   https://www.example.com/$  1 [QSA,L] </IfModule>  #END WORDPRESS 

The rewrite rule doesn’t seem to be making a difference, whether with the HTTPS or HTTP version of the URL. Images unavailable for the dev site simply don’t display, even when the same images load fine for the production site.

I also had no luck trying to adapt the rewrite rule found in this slightly different question applying to WordPress Multisite.

Additionally, I previously added a filter to stop WordPress from modifying the .htaccess file, so am pretty sure that this isn’t the cause of the problem.

What, if anything, is wrong with my rewrite rule here that’s causing it to fail?

Compare 2 images with minimum difference value

Sorry if this is the wrong place to ask this question, I’ll update/move my question if it is.

There is a linux command compare that I’m using to compare a difference between 2 images, this is the command:

compare 1.jpg 2.jpg diff.jpg

It’s working very well, the problem is: if both images has no difference, it still creates a diff file, and you open this file and it’s just a blank image.

Is there a way to tell this command to just create this diff file only if there is actually a difference between these 2 images?


Difference between UCB1 and UCT

In Bandit Based Monte-Carlo Planning by Kocsis, Levente and Szepesvári, Csaba (2006) they propose the UCT algorithm which is derived from the UCB1 algorithm.

UCB1 algorithm:
$ X_j + \sqrt{\frac{2ln(n)}{n_j}}$

with $ x_j$ = average reward for machine $ j$ , $ n_j$ = number of times j has been played and $ n$ = entire number of games played.

whereas UCT:
$ \frac{W_i}{n_i} + c \sqrt{\frac{ln(N_i)}{n_i}}$ with $ \frac{W_i}{n_i}$ win:lose ratio <–this is the same as X_j
$ c$ is temperature parameter, which is often set to $ \sqrt{2}$ (so they just put int in front..)
and $ \frac{N_i}{n_i}$ is number of total games played for parent Node / number of games played for the corresponding node, which is the same as $ \frac{n}{n_j}$ .

So what’s new here?