February 1, 2015

MightyFrame: Creating A Boot Tape

First, write the VHB with bootloader, as shown in an earlier post:

sudo dd if=vhb.miti.tape.slice1.dd of=/dev/nst0 

The "nst0" tells the tape not to rewind after writing each file, or something like that.

(Note that this is on modern Linux using a Tandberg TDC-3620 with SCSI card)

Then, add the CTIX kernel after that.  We had to "adjust" the length of this file by padding the end with sets of null bytes (Hex Value 00) until the file reached exactly 396 blocks, otherwise, we got an error saying that 395+1 blocks read, 395+0 blocks written, or to that effect.


More exactly, the error is 
dd: error writing ‘/dev/nst0’: Invalid argument
395+1 records in
395+0 records out


So, here is the command for writing the adjusted file, as well as a link to the adjusted file itself:

sudo dd if=CTIX5.11onb-to-tape of=/dev/nst0

And that's it, now you have a bootable tape! 

NOTE:  The booting of this tape still requires that certain files be on slice 1 of hard drive 0 (/dev/dsk/c0d0s1).  We have not yet figured out how to put these files onto the tape in the order they are needed for execution, or if they should be somehow integrated into the kernel.  If so, we don't have access to the special stand-alone boot kernel.  We have never had access to any "factory" bootable tape that we could read this from, so we have so far done without figuring this out.  Hopefully someday...