Questions regarding Tom Shoppa.

From: Carlini, Antonio <Antonio.Carlini_at_riverstonenet.com>
Date: Thu Apr 11 16:08:37 2002

>Are you saying the actual CD image was available as
>opposed to the many files that are on the CD?

        Yes. Four images, one per CD.
        I don't know if they vanished during the
        site reorg or whether I just cannot
        find them right now.

>satisfied it is OK. BUT, I also want to burn my own
>CD in the same manner. ALSO using Windows 98 (Yeck).

        Burning under windows is probably
        not an issue - use something like
        CDR-Win to make an exact copy
        to an image file, and then burn that.

>BUT, Can anyone help me? I want to copy that same file
>to a CD-R or a CD-RW starting at sector 212,992 (just
>like Tim Shoppa did) after I have written the files to the CD
>under the ISO file structure. Of course, I want to be able
>to do this under Windows 98!! Does anyone know if that is
>even possible, let alone how it could be done?

        I don't know the specifics of RT-11s requirements
        for the CD. I expect that RT-11 sees it as though
        it were a hard disk of exactly that many blocks
        (well 4 times the number of CD blocks because
        of the 2048<->512 byte thing).

        Many (many) years ago when I used an
        LSI-11/23 under RT-11, we had a 40MB
        drive that emulated 4 RL02 drives (or
        some such). I don't recall if this
        was done in software or hardware -
        quite possibly it was a software driver
        that came with the disk.

        Why is 212992 magic? What do you do
        to make this CD visible as 7 (or whatever)
        disks under RT-11?

        Essentially your CD is a stream of N
        2048 blocks and is presumably seen by
        RT-11 as such (at a sufficiently low level)
        and then given meaning by some
        software layer.

        A typical method for generating
        a layout with both ISO and
        "other stuff" in logically separate
        areas of the CD would be to start
        by generating a binary ISO-format
        file with just the ISO data in. The
        first 64 2048-byte blocks (or is it
        32?) are ignored by the ISO9660
        standard - they are deliberately
        not used.

        Now create an empty image file,
        the size of your CD. Overlay the
        ISO image file onto this.

        Now you slip the PDP-11
        boot block in there and add whatever
        else you need at the end in whatever
        format you want. The ISO file structure
        will be unaffected (so long as you tack
        things on after its logical end).

        What you need to find out is
        RT-11s requirements in this area.

        Actually doing this under W98
        may not be that easy. Typically,
        when I've done CDs that have
        both ISO9660 and ODS-2 on
        them, I've generated the image on
        OpenVMS and burned the image
        to CD using a PC.

        Antonio
Received on Thu Apr 11 2002 - 16:08:37 BST