> I've seen that a similar question has been asked in 2011 but I'll ask again in 
> case there are any updates. Is there any way to write 64-bit data words to MIDAS 
> banks (other than breaking them up in to two 32-bit words, such as 2 DWORDs) 
> currently? And if not, is there any plan to introduce this feature in the future?

There is no "breaking them up" as such, you can treat a midas bank as a char* array
and store arbitrary data inside. In this sense, "there is no need" for a special 64-bit bank type.

For endian-ness conversion (if such things still matter, big-endian PPC CPUs still exist), single 64-bit 
word converts the same as two 32-bit words, so here also "there is no need", once can use banks of 
DWORD with equal effect.

The above applies equally to 64-bit integers and 64-bit double-precision IEEE-754 floating point 
numbers.

But specifically for 64-bit values, such as float64, there is a big gotcha.

The MIDAS banks structure goes to great lengths to make sure each data type is correctly aligned,
and gets it exactly wrong for 64-bit quantities - all because the bank header is three 32-bit words.

bankhheader1
bh2
bh3
bankdata1 <--- misaligned
...
bankdataN
bh1
bh2
bh3
banddata1 <--- aligned
... etc

So we could introduce QWORD banks today, but inside the midas file, they will be misaligned defeating 
the only purpose of adding them.

I guess the misalignement could be cured by adding dummy words, dummy banks, dummy bank 
headers, etc.

I figure this problem dates all the way bank where alignement to 16-bits was just getting important. 
Today, in the VME word, I have to align things on 128-bit boundaries (for 2eSST 2x2 DWORD transfers).

So back to your question, what advantage do you see in using a QWORD bank instead of putting the 
same data in a DWORD bank?

K.O.