The reason I am writing this is because I have got a lot of questions about what tools I use and could recommend.

I use NASM for DOS, but I also have Turbo Assembler (TASM) installed. I find NASM easy to use but still powerful, but TASM is used a lot by others, so I have it installed. The Borland C/C++ compilers also use TASM for inline assembly. Almost all of the assembler code you can find on the internet is written in either TASM or NASM. A few programs are also written in Microsofts MASM or A86. NASM is free and open-source, and you can get it in versions for Windows, DOS and Linux.

I don't use any assembler IDE, just DOS edit.

As instruction references I use HelpPC and the NASM documentation. They are easy to find on the internet, but if you don't have them, tell me and I will send them to you.