Another approach to consider:  the failed system is SL 7.2 and does boot 
but does not bring up the GUI (e.g., ctrl-alt-F3 brings up a login 
prompt on a scrolling terminal screen and all users, including root, may 
log into the system).  I have other working SL 7.2 systems (I have had 
no time to update and have no GSRAs or Staff right now to help).  If I 
cp -pr /usr , /bin , whatever (but not /home and the like) from a 
working system to the failed system, will the failed system then be able 
to use other mechanisms for an update rather than a full new install of 
SL 7.5 followed by a restore of /home and the like?

Why was this system being upgraded?  It appears that the Palo Alto 
security systems on the end-users 802.3 network segment was 
"complaining", hopefully "fixed" by SL 7 current.  (Different security 
is used on the 802.11 networks.)

As the campus network where I work i not designed for reliable systems 
work but rather end-user files (if the network glitches, simply repeat 
the download, etc.), is there a mechanism to update from media, say 
using the iso install image from a USB thumb drive?

Thanks for any assistance.

Yasha Karant

On 08/21/2018 03:47 PM, Nico Kadel-Garcia wrote:
> On Tue, Aug 21, 2018 at 5:53 PM Yasha Karant <[log in to unmask]> wrote:
>> During the upgrade of a SL 7 non-current system to SL 7 (via yum update
>> as root from the Internet), the campus network "glitched" and the system
>> hung.  The 7.5 partially installed system panics; it has not recovered.
>> The 7 non-current will boot but no X (no GUI), only a scrolling text
>> terminal, presumably from which yum can be executed.
> If you want to keep this beastie alive, I urge you to:
>
> * Boot from a live USB or DVD image with networking enabled
> * Mount the old partitions at /mnt/sysimage, with subpartitions
> appropriately under that
> * chroot to /mnt/sysimage
> * Run "rpm --rebuilddb", because it is probably corrupt
> * Get the list of installed packages with "rpm -qa --qf '%{name}.%{arch}\n'"
> * For every package, use "yum upgrade $name" and "yum reinstall $name"
> * * yum reinstall may require enabling the obsolete repositories
> * One or more are likely to balk due to two distinct versions of the
> same package.  Resolve that balking package manually, downloading the
> current version and using "rpm -U --replacepkgs $name"
>
>> I have downloaded Scientific-7.5-Install-Dual-Layer-DVD-x86_64.iso and
>> then put this onto an USB flash "thumb" drive that I have confirmed is
>> bootable and will start the installation steps.  I do not want to do a
>> new install but rather an upgrade, not touching /home , /opt and the like.
>>
>> I have found old upstream vendor instructions for a previous upstream
>> vendor major release of the enterprise (not enthusiast) system; please
>> see below.  How are these to
>> be modified for SL 7.5?  If I boot the Install ISO image (from the USB
>> drive), is there a way to get to the old GUI upgrade option that seems
>> no longer available?
> It's nearly impossible to tell which components got messed up in a
> mass upgrade. Start from a cleaned up upgrade process, as described
> above.
>
>> Please reply to [log in to unmask]  Any assistance would be appreciated.
>>
>> Yasha Karant