[Info-vax] InfoServer 150

[Bob Wilson]

On Sunday, January 27, 2019 at 10:32:14 AM UTC-5, John E. Malmberg wrote:
> On 1/27/2019 8:12 AM, Bob Wilson wrote:
> > On Sunday, January 27, 2019 at 8:32:18 AM UTC-5, Hans Vlems wrote:
> >> It’s just bits, no problem there. Creating an image backup from a
> >> disk still won’t work when that file gets written to a cdrom. The
> >> output of dd or backup/physical may be used as input for cd writer
> >> programs on Windows. And if necessary the filetype iso should be
> >> appended to the filename.
> 
> > I agree (re: "it's just bits")...a "ISO image" is just a
> > sector-by-sector copy of physical media, which may or may not be a
> > ISO-9660 volume. Sort of like a spiral-read of the volume from block
> > 0 - maxblock.
> You are getting the terms wrong, and that can cause problems.
> 
> A disk image is a block by block image of the disk contents.
> 
> An ISO image is an image that conforms to the ISO-9660 standard.
> 
> Several disk blocks of a disk images are not used with ISO-9660 media. 
> This is intentional to allow dual format disk images by the ISO committee.
> 
> The issue that the hobbyist disks disk images have a .iso extensions yet 
> are not burned as ISO images when making CD-ROM is a frequent cause of 
> confusion on the https://www.openvmshobbyist.com/forum .
> 
> While some CD-Burner programs may treat disk images and ISO images the 
> same, many now do not.
> 
> Especially GUI based ones that validate the file contents.  If they do 
> not find the ISO structure in an alleged ISO image, they can default to 
> creating an ISO file structure and putting the disk image in it as a file.
> 
> And for disk images that are dual format ISO and other format, some 
> burner programs when you tell it that the source is an ISO image, may 
> only burn the ISO portion of the image, and not all of the disk contents.
> 
> So you need to find disk burning software that supports burning image 
> files, not just ISO images.
> 
> Only one of the hobbyist disk images have ISO-9660 content, the IA64 
> system install disk.  And that one is dual format.  The rest are disk 
> images.
> 
> Due to their age, I suspect that the Inforserver disk images are not iso 
> images, even though that they may be named as such.
> 
> HPE/VSI has an internal port of mkiosf that is used as part of creating 
> that disk image.  It may not be usable for making other types of images, 
> as stuff that was not needed for making the IA64 boot was removed if it 
> caused compile/link issues.  (There is a layer in the source that is a 
> wrapper for all the syscalls that was removed)
> 
> This was needed for creating the El-Torito DVD boot required by the 
> Itanium console, which existing ports of mkiosf did not support.
> 
> If someone is motivated to properly update the port of mkiosf to VMS, it 
> would be nice to add dual format ISO/OD5 support natively.  With that 
> support, when you mount the disk as ISO-9660, you would also see all the 
> VMS files.  That would likely involve making sure that the trans.tbl 
> files are generated for full compatibility.
> 
> Regards,
> -John


John, could you please give me a pointer to the "official" (whatever that means) definition of "ISO image".

Thanks,
bw