I think and believe that i could start both the two OS from HardDisk until i installed Turbo Linux after the SCO unix .
If I do anything ,Ican only start Turbo,but if i run "fdisk /mbr",the SCO unix can normally start,but the Turbo Linux could not start with unless you insert the bootdisket,which is not a good thing.
this comes the question:How can i get a good result ------no need for the Turbo bootdisket?
thank you in advance!
my OICQ is 46767111,thanks a lot!
[email]sensir163@163.com[/email]
Try to search for Multi Boot in this forum
Or check/surf in the intrenet for any Software providing webpages which gives the utility to multiboot two or 3 OS in one time. There is some for Linux and other Unix's im sure you can find for one without using a boot disk.
yo can use lilo to chose what os boot.
but first you must configure your /etc/lilo.conf 
i solved the problem yesterday .It's funny that I saw the system display the message "The system is writing the configureinfo to /etc/lilo.conf "after i use the tool "turbofscofg",through which i do the "Boot Record".Then i know i may see the file /etc/lilo.conf is what.------So,i edited it---And then ,the system is OK!Now i can go into any OS from the Turbo Linux lilo menu,including SCO UNIx,DOS(Win98,winXP),and Turbo Linux itself------Now, no need for the boot disk .
Thank you ,killerserv and comadreja,thank you very much!