China DOS Union

You said
1、 SET EXPAND=YES
2、 SET DIRCMD=/O:N
3、 set LglDrv=27 * 26 Z 25 Y 24 X 23 W 22 V 21 U 20 T 19 S 18 R 17 Q 16 P 15
4、 set LglDrv=%LglDrv% O 14 N 13 M 12 L 11 K 10 J 9 I 8 H 7 G 6 F 5 E 4 D 3 C
Now there is already a much better solution than this.
What method is it? Please give some guidance.
And can the program still run normally?

Also, what do these two lines mean:
CDA %CDROM% > NUL MD %RAMD%:\TEMP

Use the FINDRAMD command from my Super MS-DOS 7.10 boot disk, one command is enough.

And CDA can also be replaced with the smaller and better DREADY.

I don't understand DOS very well.
Could you explain it a bit more clearly?
Thanks

findcd can find the CD-ROM drive and set the %cdrom% variable;(findcd is in the moderator's boot disk)
CDA %CDROM% > NUL ;check whether the cdrom is ready, I suggest using dready instead
MD %RAMD%:\TEMP ;create a temp folder under %radm%:\