IBM 5100 Tape Usage Demonstration (internal and external IBM 5106) with Ball Bounce surprise at end

Having come across an IBM 5100 (from 1975) that is fully functional, including both the internal and external tape units, I decided to make a video of this usage to have on record how that experience was.
More info available at:
voidstar.blog/...
PHASE 1
00:00:14 Insert QIC DC6150 tape
00:00:30 "MARK 3,2,1" of the tape
00:00:40 MARK finish, brief explanation of MARK
00:01:22 Proceed demo ("UTIL" command is like DIRECTORY)
00:01:54 Multi-CRT demonstration
00:02:37 UTIL issued to show no listing (show that must REWIND first)
00:02:50 REWIND/UTIL shows the filenames
00:03:00 LOAD 0 (this clears memory, what most people expect as "NEW")
00:03:37 Modify program, SAVE to file 1 with a new modified filename
00:04:50 LOAD and modify file 2
00:05:43 RUN brief run of the modified program and save
the modified program back to file 2.
00:06:09 REWIND/UTIL to show modified filenames
00:06:27 clear (LOAD 0) and reload file 1
00:06:49 LOAD 2, back to the modified version 2,
brief run demo
00:07:23 conclude initial tape usage demonstration (end phase 1)
PHASE 2
00:07:37 "MARK 8,5,1" show effect of re-MARKing an existing MARKed tape.
00:07:52 "ERROR 158" is "Are you sure?" indicator
00:07:59 graph showing progress of MARKing 8KB files
00:09:22 "LOAD 1,E40" demo to show loading from the external 5106 tape unit
00:10:20 LOAD 0 and load the file again from E40.
00:11:09 "MARK 3,2,1" (full 5100 view only)
00:11:22 confirm re-MARK with "GO"
00:11:46 "UTIL DIR 1" to show all files (blank)
00:12:02 "MARK 2,5,1" (with close up view)
00:12:12 "GO" (using ATTN to clear the end of line)
00:12:33 "UTIL" to (again) show that UTIL while at end of the data portion can be misleading
00:12:36 "UTIL DIR 1" use this to automatically
rewind back to file 1 and show the fill file listing
from that point on.
00:13:07 Load (again) the sample BASIC program from
E40 (external) since all memory and files on E80
have been cleared.
00:13:18 save program back to E80 file slot 1
00:13:42 save program to E80 file slot 2, but this time
showing how long the filename can be (limit 17 characters).
00:15:06 using UP/DOWN arrow keys to edit existing program
change program intro and show four computed values
per line.
00:16:04 brief program sample run
00:16:14 longer program sample run
00:16:25 longer program sample run with "large screen"
00:16:37 show R32 vs L32 switch effects
00:17:08 very long program sample run on "large screens"
00:17:14 show all three external CRTs
00:17:17 reducing the contrast on the 14" JVC monitor
to fix the smearing issue. (this is a monitor issue,
it just does this the longer it is on)
00:17:55 use of R32/L32 modes during long program runtime
00:18:37 back to program listing, end demo phase 2
PHASE 3
00:18:38 "UTIL DIR 1,E40"
00:18:52 HOLD, CMD-MINUS entering the DCP
diagnostic control program
00:19:04 altering address 2000 to enter the
"show all character symbols" program.
00:19:11
The actual entering of the machine code is
fast forwarded because it is already shown
on a prior video demonstration. The reason
it is being entered again is to save it as a
RWS DUMP to a file.
00:19:25 "BR 2000" to briefly show the program
running (and verify it was entered correctly)
00:19:38 "C"-9 to write the RWS DUMP to a tape file
file type is "0048" since that is HEX version of 72.
00:20:22 saving of RWS DUMP to a tape file
00:20:30 notice the "garbage" at the bottom of screen,
00:20:35 one of the ROS addressing check programs
00:20:43 RAM TEST (notice the DCP uses the word RAM instead of RWS).
00:20:58 local CRT view of the test.
00:21:11 RESET system, to prepare to show how to load the dump from file. RESET ensures
clearing of the memory.
00:21:25 UTIL DIR 1 to show file type 72 written to file 3.
00:21:49 enter DCP to begin loading the dump
00:22:06 before loading the program, I do "D 2000" to show the existing memory contents (and that it is not already equal to the test program).
00:22:20 "C"-8 to issue load dump command (tape file back to RAM)
00:22:40 "BR 2000" to run the loaded binary program
PHASE 4
00:22:52 aded modern LCD screen to the BNC chain of output showing a full boot-up sequence
NOTE: the audio is different in this portion, it is recorded directly off the action camera that is further away
00:23:20 "UTIL DIR 1" result, notice file 4 is type "P4"
00:23:31 "C"-8 to load the dump from tape to RAM. Using address 0B00.
00:23:46 "D 0B00" to show the program contents. Some of you might recognize it. Quick preview of the code (to make sure it loaded ok).
00:24:02 "BR 0B00" to run this mystery program.
00:24:38 showing registers while program runs
00:25:41 reset, and to show some BASIC samples