<p>The <code>blk?????.dat</code> files aren't individual blocks. Rather, they are files that contain multiple blocks concatenated together, in the order Bitcoin Core downloaded them. Once a maximum size is reached, further blocks will be written to a subsequent file.</p>
<p>Bitcoin Core downloads blocks out of order, as it schedules block queries from multiple peers at once.</p>
<p>There is no guarantee that any two nodes receive blocks in the same order, and thus also no guarantee that they end up in the same files or even the same position within those files.</p>

CC BY-SA 4.0
2022-04-23T20:36:06.257Z
2022-04-23T20:36:06.257Z
Pieter Wuille
<p>That was the talk that Dan Kaminsky introduced the tribute and didn't really explained why. <a href="https://www.youtube.com/watch?v=hLIYq3ePaX4&amp;t=502s&amp;ab_channel=DennisMuller" rel="nofollow noreferrer">https://www.youtube.com/watch?v=hLIYq3ePaX4&amp;t=502s&amp;ab_channel=DennisMuller</a></p>
<p>On my full node it doesn't really appear to be the same thing.</p>
<pre><code>~/.bitcoin/blocks# strings -n 20 blk00001.dat
=ybegin line=128 siz
e=8776 name=bitcoin.
***2*.+D*/***+***h+E
*/***+***p+R*-***+*,
**+[*,***;***x******
0010/211133246&gt;76556
C&lt;=}9&gt;GDIHGDFFJNXQJL
VMFFRaSVZ[^^^IQcgb\f
KFK\\\\\\\\\\\\\\\\\
\\\\\\\\\\\\\\\\\\\\
+/++++++********+,-.
DPQRST_`abcdmnopqrst
*&gt;{o*&gt;{o*&gt;{o*&gt;{o*&gt;{o
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
z+o&gt;z+o&gt;z+o&gt;z+o&gt;z+o&gt;
</code></pre>
<p>But it appears on block 3:</p>
<pre><code>~/.bitcoin/blocks# strings -n 20 blk00003.dat
---BEGIN TRIBUTE--- 
#./BitLen           
::::::::::::::::::: 
:::::::.::.::.:.::: 
:.: :.' ' ' ' ' : : 
:.:'' ,,xiW,&quot;4x, '' 
:  ,dWWWXXXXi,4WX,  
' dWWWXXX7&quot;     `X, 
 lWWWXX7   __   _ X 
:WWWXX7 ,xXX7' &quot;^^X 
lWWWX7, _.+,, _.+., 
:WWW7,. `^&quot;-&quot; ,^-'  
 WW&quot;,X:        X,   
 &quot;7^^Xl.    _(_x7'  
 l ( :X:       __ _ 
 `. &quot; XX  ,xxWWWWX7 
  )X- &quot;&quot; 4X&quot; .___.  
,W X     :Xi  _,,_  
WW X      4XiyXWWXd 
&quot;&quot; ,,      4XWWWWXX 
, R7X,       &quot;^447^ 
R, &quot;4RXk,      _, , 
TWk  &quot;4RXXi,   X',x 
lTWk,  &quot;4RRR7' 4 XH 
:lWWWk,  ^&quot;     `4  
::TTXWWi,_  Xll :.. 
=-=-=-=-=-=-=-=-=-= 
LEN &quot;rabbi&quot; SASSAMA 
     1980-2011      
...
...
...
</code></pre>
<p>Apart from the Dan Kaminsky &quot;bug&quot;, I think this shouldn't happen. Right?</p>

<blockchain>
If the Bitcoin blockchain is immutable, why the Len Sassaman's tribute moved from one block to another?
Vitor Duque
# If the Bitcoin blockchain is immutable, why the Len Sassaman's tribute moved from one block to another?

(Asked by: username_0 on 2022-04-23)

That was the talk that Dan Kaminsky introduced the tribute and didn't really explained why. <https://www.youtube.com/watch?v=hLIYq3ePaX4&t=502s&ab_channel=DennisMuller>

On my full node it doesn't really appear to be the same thing.

```
~/.bitcoin/blocks# strings -n 20 blk00001.dat
=ybegin line=128 siz
e=8776 name=bitcoin.
***2*.+D*/***+***h+E
*/***+***p+R*-***+*,
**+[*,***;***x******
0010/211133246>76556
C<=}9>GDIHGDFFJNXQJL
VMFFRaSVZ[^^^IQcgb\f
KFK\\\\\\\\\\\\\\\\\
\\\\\\\\\\\\\\\\\\\\
+/++++++********+,-.
DPQRST_`abcdmnopqrst
*>{o*>{o*>{o*>{o*>{o
z+o>z+o>z+o>z+o>z+o>
z+o>z+o>z+o>z+o>z+o>
z+o>z+o>z+o>z+o>z+o>
z+o>z+o>z+o>z+o>z+o>
z+o>z+o>z+o>z+o>z+o>
z+o>z+o>z+o>z+o>z+o>

```

But it appears on block 3:

```
~/.bitcoin/blocks# strings -n 20 blk00003.dat
---BEGIN TRIBUTE--- 
#./BitLen           
::::::::::::::::::: 
:::::::.::.::.:.::: 
:.: :.' ' ' ' ' : : 
:.:'' ,,xiW,"4x, '' 
:  ,dWWWXXXXi,4WX,  
' dWWWXXX7"     `X, 
 lWWWXX7   __   _ X 
:WWWXX7 ,xXX7' "^^X 
lWWWX7, _.+,, _.+., 
:WWW7,. `^"-" ,^-'  
 WW",X:        X,   
 "7^^Xl.    _(_x7'  
 l ( :X:       __ _ 
 `. " XX  ,xxWWWWX7 
  )X- "" 4X" .___.  
,W X     :Xi  _,,_  
WW X      4XiyXWWXd 
"" ,,      4XWWWWXX 
, R7X,       "^447^ 
R, "4RXk,      _, , 
TWk  "4RXXi,   X',x 
lTWk,  "4RRR7' 4 XH 
:lWWWk,  ^"     `4  
::TTXWWi,_  Xll :.. 
=-=-=-=-=-=-=-=-=-= 
LEN "rabbi" SASSAMA 
     1980-2011      
...
...
...

```

Apart from the Dan Kaminsky "bug", I think this shouldn't happen. Right?

**Tags:** blockchain


---

## 1 answers

### Answer by username_1 on 2022-04-23. Score: 5 | Accepted answer

The `blk?????.dat` files aren't individual blocks. Rather, they are files that contain multiple blocks concatenated together, in the order Bitcoin Core downloaded them. Once a maximum size is reached, further blocks will be written to a subsequent file.

Bitcoin Core downloads blocks out of order, as it schedules block queries from multiple peers at once.

There is no guarantee that any two nodes receive blocks in the same order, and thus also no guarantee that they end up in the same files or even the same position within those files.


---

