What do you mean exactly? A bootable rescue disk? The formats for bootable disks (MBR, location of bootloader, partition tables etc.) conform to a standard, but rescue disks for individual operating systems will work only with that particular OS.
someone told me it's good to have a bootable MBR floppy disk so I thought I would ask the forum for it's opinion. Yes, a bootable rescue disk for MBR only.
MBR = master boot record, can fix some problems with FDISK /mbr command. But http://www.cknow.com/vtutor/FDISKMBR.html