Distinguishing between hardware, software, and operator induced symptoms

[Richard Owlett <rowlett@cloud85.net>]

As noted in the "Invoking ddrescue" thread 
[https://lists.debian.org/debian-user/2016/11/msg00641.html], my 
laptop [dedicated to educational/experimental projects which 
could fail spectacularly] used to apparently successfully run 
ddrescue, malfunctioned.

<*BACKGROUND*>
The laptop is a used Lenovo R61 running Debian 8.6.0 with MATE 
D.E. installed from purchased set of DVDs. The "damaged" and 
destination drives were connected by separate USB adapters [each 
powered by separate wall warts].

Sequence of events:
A. Run ddrescue
   1. Power on laptop, responding "root" at login prompt.
   2. To force predictable /dev/sdX assignments, sequentially 
connect destination
      and "damaged" drives.
   3. Apparently run ddrescue to a successful conclusion.
   4. Disconnect "damaged" drive.
   5. Power down for the night.
B. Setup to extract data in useful format from the rescued partitions
   [There are missing details as I report from memory, log files 
do *NOT* exist]
   1. Power up sequence fails to run successfully
      a. systemd reports it's checking a partition with mounting 
problems
         [it is the same message as when the UUID of the swap 
partition does
          not have the expected value.]
      b. I notice that wall wart for the destination drive is 
unplugged.
         I power down, plug it in, power up laptop.
      c. systemd again reports mounting problem. I allow 
sequence to continue.
         I never receive login screen and assume fatal error 
related USB drive.
      d. Power down, disconnect USB drive, attempt reboot from 
scratch.
         i. Don't recall if systemd complained that USB was not 
present.
            [It is mentioned in /etc/fstab -- see previous thread.]
        ii. Boot sequence appears to run to point where 
appearance of login
            screen expected. It does not. I'm not able to glean 
useful information
            from log files.
    2. Decide to reinstall as there is no valuable data on the 
hard-drive.
       a. Neither the Install nor Live DVD's will load.
       b. On a second machine dd the Install DVD to a flash drive.
          It installs as expected.
< end *BACKGROUND*>




QUESTIONS:

A. Hardware diagnostics [as CD has already proved unreliable]
   1. Memory - I have memtest86+, will have to put it on flash drive
   2. Hard disk - Somewhere I have a Seagate specific diagnostic 
which has
      proved useful on non-Seagate drives. Is there a 
recommended more
      generic diagnostic?
   3. Are there recommended [for want of a better term] board 
level diagnostics
      that do not depend on an OS already being installed?
B. OS integrity checks
   I would assume that being able to login without noticing any 
thing is a
   fairly good check. However, I have experience symptoms which 
may have multiple
   unrelated causes. Is there a suggested system integrity check?
C. Other
   I have a typical collection of diagnostic CD/DVDs from which 
I can create
   equivalent iso files. I have a vague recollection of a 
procedure to put GRUB
   [or was it LILO?] on a bootable flash drive with multiple iso 
files and being
   able to choose which to boot. Ring any bells? Suggested 
search terms?

TIA