The tape has QIC-11 formatted data across the first 3 tracks of the tape, and appears to be all one file, (with only one filemark at the end of the data on the 3rd track). Track 4 appears to be blank.
It's approximately 13.7Mb file, and it can be downloaded for analysis here.
I used my own home-grown process (detailed post coming soon) to extract the data from this tape.
There are remarkably few strings found in this large (for the era & the 20Mb tape) file, which I have extracted and display below:
MAG TAPE DIAG OP020007-001C
SELECT DEVICE ADDRESS:
SELECT UNIT?
TYPE (1) NRZI (2) PE?
STATUS DENSITY BIT 4 (0) OFF, (1) ON ?
STATUS PE IDENT BIT 11(0)OUT, (1)IN?
SELECT TEST
(1) DIAGNOSTIC
(2) EOT TEST
(3) DATA LATE
(4) WRITE LOCK
TURN POWER OFF ON TAPE DRIVE
REMOVE WRITE ENABLE RING. DONT STOP PROGRAM
WRITE LO
CK BIT OFF: 100201
WRITE LOCK TEST OK, PUT RING BACK ON TAPE
NO DATA-LATE BIT
DATA LATE TEST-PRESS STOP AND CONTINUE
EOT TEST
ERROR STATUS FOLLOWING WRITE
END OF TAPE OK, REWIND
SUCCESSFUL PASS
** TERMINATE **
AC0 =
AC1 =
AC2 =
PC =
DATA LATE TEST IS OK
CYCLE, ERRORS =
-?-
|P515Q
ALRAL0L1T0T1EVODWD
0!+)(A
'I(Y
(A&AI !)
MAG TAPE RELIABILITY OP020008-001C
SELECT DEVICE ADDRESS:
SELECT UNIT?
TYPE (1) NRZI (2) PE?
STATUS DENSITY BIT 4 (0) OFF, (1) ON ?
SELECT TEST
(1) RELIABILITY TEST
(2) INTERCHANGE TEST(READ & WRITE)
(3) INTERCHANGE TEST(READ ONLY)
(4) TEST LOOP BUILDER
-?-
BAD
DATA ERRORS
MMAND
MMAND
MMAND
MMAND
Does anyone know more about this IRIS install, either for the Microtech or for the Point 4?
Google finds nothing on those specific numbers, but quoted "MAG TAPE RELIABILITY" brings up some vague articles and documentation on those utilities in the mid 70s and early 80s. Nothing Microtech or Point 4 related, though. The closest I see was mention of the DG Nova in the 1975 computerworld article on BALL computers.
I should note that I was somewhat surprised to find the QIC-11 format instead of the Kennedy 6450 format I described earlier on this site. I assumed that this handwritten label on the edge of the tape had meant that the user had written a LU0 backup over the IRIS install, and because the write-protect plug was turned to "unsafe" when I acquired the tape.
...but then the data format would have at least been in the same format as the other tapes backup tapes (Kennedy 6450 format), right? This was clearly a clean QIC-11 format on tracks 0, 1 and 2.
Furthermore, it didn't fit the layout of the data I see on the other tapes with the Logical Units & Positions, as I describe here.
Tracks 5-8 may or may not have something on them, but seem to be very bad data reads, not clean like the first 3 tracks I show.
It could be that its only a 4-track written format (tracks 0-3), and so tracks 4-8 might be reading just the edges of the wider 4-tracks, thus the really bad reading data pulses. OR, this bad data could be from previously written data on the tape, and it
Again, note that track 3 was blank, which, if the tape were 4-track QIC-11, would have been the final official track available.
I'll do more analysis on those other tracks if I can, and update here soon, but it will be difficult. I would consider what I read on tracks 4-8 to be erratic enough that it is nearly impossible to read...much more so than other things I have accomplished in this area so far.
See my posts about this topic at:
vintage-computer.com
MARCH email group
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