Use Debug Command to Dump BDA

We can use debug command in Windows prompt to dump BDA (BIOS Data Area.) The BDA is created at memory location 0040:000h with a 256 bytes or over.

The word in 40:0e is the segment address of EBDA. The address is 9ac0:0000. We can use debug to dump it.

The word in 40:13 is the system available memory size in Kbytes below 640k. The value is 0280h = 640. Therefore the memory size is 640k.

We can refer the following link for the detail of  BDA.
http://www.bioscentral.com/misc/bda.htm