11 Apr
2002
11 Apr
'02
4:08 p.m.
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