attrib/chmod on old dos version

attrib/chmod on old dos version

I'm working on an old pc with dos 5.0 installed. I have plugged in a
storage media on it, PC can easily see the directories and files, but i
cannot overwrite or add directories/files.
So, if i would like to change permissions to one directory, how can i do
this? I have tried with: attrib +a +r a:\DIR1 /s /d
[but the /d option is not enabled on this old version of attrib and so it
doesn't work] I tried to download a latest version of attrib, but it gave
me the message "DOS version not supported".
The moral is that i would like to do the same of linux's CHMOD in DOS 5.
I really need your help! i have searched in every site (google ecc.) but i
didn't succeeded in finding the right solution.
thanks, have a nice day
dimakx
p.s.=if you know a third party software , too, that works in DOS 5 and
could help me, please: notify me :)