Re: usb-hybrid, usb-hdd and what way to get verbose output on CLI ?

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

> what's the difference between usb-hybrid iso's and usb-hdd .img's 

The ISO hybrids contain in their first 32 kB a Master Boot Record
for BIOS booting from hard-disk-like devices, and maybe a
GUID Partition Table for EFI booting from hard-disk-like devices.
They may even contain an Apple Partition Map which leads the
booting system to a HFS or HFS+ filesystem tree.

Booting fom CD, DVD, or BD starts not at an MBR or GPT but at
an El Torito boot record. This is present by default in a
bootable ISO image.

Booting from ISO images is highly technical stuff. I myself
understand only the earliest steps, for which i have to prepare
the output of xorriso. All further steps are the job of the
bootloader program that sits in the ISO image.
What i learned so far is collected in
  http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/view/head:/doc/boot_sectors.txt


> cat debian.iso > /dev/sdX
> The question is, is there a way to get verbose output ?
> Is there a way to get some sort of progress bar [...] ?

You could install some entertaining filter between the cat
process and the device.
Like

  cat debian.iso | $(scdbackup -where bin)/raedchen -step 1M >/dev/sdX

which would report progress in megabyte steps.
("raedchen" stems from my backup tool scdbackup.
 Such a filter is not hard to program. Just read data from
 stdin, count them, put them out on stdout, and print some
 entertaining message to stderr, when enough bytes have been
 counted.)

Maybe there is a GUI file management tool which can copy
a data stream to /dev/sdX. It has to be able to write data
to a file without objecting that it already exists and without
removing and re-creating it.


> Also do I have to unmount the device before doing the above.

Oh yes. You really should umount.
Especially if the target device is mounted with write permission.
In that case, some inadverted write operation of the file system
driver could alter your ISO image and cause interesting effects
when it shall be used for booting or software installation.


Have a nice day :)

Thomas