How do I compose music for doom1/2?

[CacoPinky]

How do I compose music for doom with the right sound and in a manner that makes it sound similar to the original tracks? 

 

What software or set of things would I require? 

 

I have this song stuck in my head that I heard from a specific metal band and in my opinion it would sound quite great as a doom version. 

[Alper002]

Any program that can make MIDI files should do.

Doom's music is kind of made out of MIDI files, so anything made with them should sound like Doom if you choose the right instruments.

 

That said, I don't know any exact programs to do that, but at least I have pointed you in the right direction.

[WalterAB]

Guitar Pro is a great software for writing MIDI music. It has easy to use interface, it's pretty lightweight, and it's quite simple to export your projects into MIDI.
I recommend Guitar Pro 5 over the newer GP6, as it works better with midi.

[Nine Inch Heels]

In case you didn't already, have a look at "aria maestosa". It's free to use, just like for example sekaiju, and I found it relatively easy to understand, which -coming from somebody like me who's never really used a program like that before- might just be what you're looking for.