Using bootstrings

A bootstring is a special command or text string that is entered at the Boot: prompt displayed at system startup. Normally this process is transparent to the operator because when you press <Enter> at the Boot: prompt, the system uses a pre-defined bootstring such as hd(40)unix specified by DEFBOOTSTR in /etc/default/boot.

There are special bootstrings that permit you to define device configurations that override system defaults (without relinking the kernel). For example, you might be using a tape drive at a non-standard address or the system might not be recognizing your host adapter correctly. In a similar way, new device drivers that are not supplied with SCO OpenServer systems can be installed from a floppy disk using the link bootstring.

To define or redefine a device at boot time:

1. Decide which bootstring you need to use. The most common are listed here:

   • Advanced Power Management -- apm

   • SCSI peripherals -- Sdsk, Stp, Srom, Sflp

   • SCSI host adapter -- adapter, ad160, alad, blad, ciss, clad, mylex

   • IDE/ATAPI host adapters and peripherals -- wd

   • Root hard disk -- hd

   • QIC-02 tape drive -- ct

   • Disable drivers -- disable

   • Memory -- mem

   • Cache -- cache

   • System console -- systty

   Make certain the bootstring parameters you use match your hardware configuration. Additional bootstrings are documented in the boot(HW) manual page.
   

2. Turn the machine on and wait for the Boot: prompt. If you are performing an installation, note that this is the only time the Boot: prompt appears; you are not given the opportunity to reboot during the installation.

   Now enter the necessary bootstrings separated by spaces. For example:
   
   defbootstr Stp=wdha(1,1,0)

defbootstr must be included on the boot line. The system then boots according to the information you provided. If you entered the bootstring incorrectly, an error message is displayed.

For additional information on the boot process and bootstrings, see ``Configuring devices with bootstrings'' and the following manual pages: boot(HW), boot(F), bootstring(HW), link(HW), and mem(HW).