You can assemble Retro UNIX 386 v1.1 source code by using NASM (v2.11)... ((unix386.s is the main source file, includes other source files via %include directive)) Example: nasm unix386.s -l unix386.txt -o unix (For above example, all of Retro UNIX 386 v1.1 kernel --".s" & ".inc"-- source files must be in the nasm program directory... But, you can use another directory or you can copy files between nasm directory and your working directory; for axample, you can use 'runix' directory as working dir.) (Read NASM manual for details...) ****** Then you can copy 'unix' binary/kernel to root directory of the Retro UNIX 386 FS floppy disk... by using 'UNIXCOPY.COM' program Example: fromdos c:\nasm\unix /unix ****** In order to make a new Retro UNIX 386 bootable fd (1.44MB, 3.5")... you can use UNIXFDFS.COM program or you can continue to work on Retro UNIX 386 with sample 1.44MB floppy disks with bootable Retro UNIX (386 v1) FS images.