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tape formatting under RSX11

hush

Experienced Member
Joined
Feb 7, 2022
Messages
316
Location
MD, USA
hey all! i recently picked up a TK70 with some tapes for my 11/83, and i've been having a bit of trouble with it. from a sysgen perspective the device works fine- lives at MU0:, correct CSR and vector addresses, and i can interact with it without error- but i'm not able to format the tape for use. i tried just a normal INI MU0:USRDAT with no flags, but that results in:

Code:
>PIP MU0:/FR
PIP -- Failed to open storage bitmap file
MU0:[0,0] -- Bad tape format

the only flag i can see in HELP INI SUM that may be relevant is /DENSITY, but it doesn't seem like omitting it would prevent the tape from working:

Code:
/DENS also checks the density of a diskette in an RX02 drive. If you specify
 a value for /DENS, the drive density is compared to the actual value for
 consistency. If you do not specify a value, INI initializes the volume at its
 current density without performing a consistency check.

i have tried three different tapes, but unfortunately i only have the one TK70. it appears to be working fine though, LEDs light up during activity and loading/unloading, and i can hear it churning away when accessed. is there some special INI/BRU incantation to format a tape? thank you in advance!
 
Last edited:
The TK70 should be figuring out the density of the tape based on the header. You can erase it by exposing the first couple of feet to a good magnet (I did this with the tape drive open and a magnet along the tape path) at which point the drive will put a new header on (TK70 I think) the next time you format.

Using a TK50 tape as a TK70 tape is technically "bad" but it does work.

Bigger question is what's the condition of the drive? The capstains have tachometers under them to sense tape motion at the head, and if the oil on the bearings has dried up they will not track properly. You can take off the nuts (mark each one and carefully count the number of turns so you can put it on at the same height) then remove them and either replace the bearings or (easier) just put a bit of watch oil in each one to bring them back to factory.

I have fixed several TK50's and TK70's this way and they work fine as backup devices for both RT11 and RSX11M+

C
 
The TK70 should be figuring out the density of the tape based on the header. You can erase it by exposing the first couple of feet to a good magnet (I did this with the tape drive open and a magnet along the tape path) at which point the drive will put a new header on (TK70 I think) the next time you format.

Using a TK50 tape as a TK70 tape is technically "bad" but it does work.

Bigger question is what's the condition of the drive? The capstains have tachometers under them to sense tape motion at the head, and if the oil on the bearings has dried up they will not track properly. You can take off the nuts (mark each one and carefully count the number of turns so you can put it on at the same height) then remove them and either replace the bearings or (easier) just put a bit of watch oil in each one to bring them back to factory.

I have fixed several TK50's and TK70's this way and they work fine as backup devices for both RT11 and RSX11M+

C
the drive should be in good physical condition, but i have no idea how long it's been in storage for so it's entirely possible the oil has dried up as you said. i'll pull it out sometime this week and take a look!
 
Yeah, I think when I back up my rsx+ system I just boot BRU64k from 8 inch floppy, then do a simple mu:=du0: type command.

Can you boot RT11? It supports the tape as a Files11 device,and you can do inits and such.
 
BRU -- *FATAL* -- Initialize qualifiers invalid when output is tape
My memory failed me
BRU/MOU/VER LB: MU:

Code:
>MOU MU:/FOR
>BRU/MOU/VER LB: MU:
BRU - Starting Tape 1 on MU0:

BRU - End of Tape 1 on MU0:

BRU - Starting verify pass Tape 1 on MU0:

BRU - End of Tape 1 on MU0:

BRU - Completed

>

Can you boot RT11? It supports the tape as a Files11 device
RSX too
Code:
>INI MU:TEST
>DMO MU:/LOCK=V
10:38:34  *** MU0:  -- Dismount complete
DMO -- TT0:    dismounted from MU0:    *** Final dismount initiated ***
>MOU MU:/OVR/VI
Volume Information
Class:       ANSI labeled tape
Device:      MU00
Fileset ID:  TEST
Volume ID:   TEST
Owner:       [1,1]
Processor:   MTAACP
>PIP MU:=LB:[1,2]*.*;*
PIP -- Open failure on input file
DU0:[1,2]RMSDES.IDX;1 -- Bad record type
>PIP MU:[*,*]/LI/RW


Directory MU0:
2022-12-03 10:39

STARTUP.CMD         ;1        10.        2022-12-03 00:00
QMGSTART.CMD        ;1        5.         2022-12-03 00:00
QMGSTOP.CMD         ;1        1.         2022-12-03 00:00
SHUTUP.CMD          ;1        1.         2022-12-03 00:00
QIOSYM.MSG          ;1        29.        2022-12-03 00:00
BATCH.TXT           ;1        2.         2022-12-03 00:00
LOGIN.TXT           ;1        2.         2022-12-03 00:00
INDSYS.CLB          ;1        130.       2022-12-03 00:00
ACC.HLP             ;1        16.        2022-12-03 00:00
ASCII.HLP           ;1        9.         2022-12-03 00:00
BAD.HLP             ;1        5.         2022-12-03 00:00

............

TKTN.HLP            ;1        2.         2022-12-03 00:00
VCP.HLP             ;1        77.        2022-12-03 00:00
VFY.HLP             ;1        7.         2022-12-03 00:00
VMR.HLP             ;1        105.       2022-12-03 00:00
ZAP.HLP             ;1        36.        2022-12-03 00:00
ADDONS.CMD          ;1        1.         2022-12-03 00:00
C.CMD               ;1        1.         2022-12-03 00:00

Total of 3872./3872. blocks in 202. files

>PIP MU:/FR
PIP -- Failed to open storage bitmap file
MU:[0,0] -- No such file
>
But command PIP MU:/FR for tape is wrong
 
Yeah, I think when I back up my rsx+ system I just boot BRU64k from 8 inch floppy, then do a simple mu:=du0: type command.
Code:
>BOO [6,54]BRUSYS

RSX-11M/RSX-11M-PLUS STANDALONE COPY SYSTEM V4.8


RSX-11M/RSX-11M-PLUS Standalone Configuration and Disk Sizing Program

Valid switches are:
        /CSR=nnnnnn to change the default device CSR
        /VEC=nnn to change the default device vector
        /FOR=n to change the default magtape formatter number
        /DEV to list all default device CSR and vectors


Enter first device: DU:

Enter second device: MU:

Hit RETURN and enter date and time as 'TIM HH:MM MM/DD/YY'
RUN BRU
>
BRU>/VER DU: MU:
BRU - Starting Tape 1 on MU0:

BRU - End of Tape 1 on MU0:

BRU - Starting verify pass Tape 1 on MU0:

BRU - End of Tape 1 on MU0:

BRU - Completed

BRU>
 
this worked, but it looks like something more is going on, parity error on the drive:

Code:
>BRU/MOU/VER LB: MU:
BRU - Starting Tape 1 on MU0:

BRU -- *WARNING* -- Tape write error on MU0:
I/O error code -4

BRU - Mount another tape

BRU - Mount Tape 1 on MU0:

>
BRU - Mount Tape 1 on MU0:

BRU - Starting Tape 1 on MU0:

BRU -- *WARNING* -- Tape write error on MU0:
I/O error code -4

BRU - Mount another tape

it seems unlikely that i have five bad tapes, more likely that i have one bad TK70. could this be hardware?
 
If all five tapes behave in the same way, then the problem is most likely in the tape drive. Does BRU display an error immediately or does a certain amount of recording pass? If right away - almost certainly a tape drive. But here I can’t help you anymore - I am an experienced programmer and a beginner electronics engineer :)
 
I'd check the capstains. When you flick them with your finger do they roll easily or drag? Try putting a tiny drop of oil on the top bearing (you can do this without taking them apart), then after it has soaked in wipe it clean with a paper towel and try spinning. If better see if the tape works.
 
If all five tapes behave in the same way, then the problem is most likely in the tape drive. Does BRU display an error immediately or does a certain amount of recording pass? If right away - almost certainly a tape drive. But here I can’t help you anymore - I am an experienced programmer and a beginner electronics engineer :)
it takes a little bit for the error to occur, it isn't immediately after the write pass starts which is why it feels like it's the tape, but it's also all of them... these were ebay pulls but they were sold as working, so i would assume (or hope...) out of five i'd have at least one good tape. i have some TK50 tapes lying around i can try, i'll have to dig them up since i have no idea where i put them after my TK50 broke :x
I'd check the capstains. When you flick them with your finger do they roll easily or drag? Try putting a tiny drop of oil on the top bearing (you can do this without taking them apart), then after it has soaked in wipe it clean with a paper towel and try spinning. If better see if the tape works.
i will check this, thank you!
 
Side note: Since I have been installing Decnet and TCP/IP on my 11/83 here I figured it was time for a backup. I found some tapes last year and decided to give them a go.

Simple summary: They are garbage. Noisy and caused the drive to unspool. Reason was the tape binder was coming off on the head and making a complete mess. Cleaned head, tried another tape, worked for a bit then failed. Head dirty again. Tossed all of the tapes in the garbage and tried a known good tape. Works fine and I'm doing a backup now.

Before I started I checked my capstains. The one on the rear (with the tachometer) was dragging a bit so I marked the bolt, counted the turns to remove it, and removed the capstain for re-oiling. Put it back in, and everything was good, but it looks like watch oil will need to be refreshed in 3 or so years.

Maybe lithium grease would be better to re-lube the bearings. Or maybe it's time to just press the old ones out and put new ones in. Hm. I'll check my TK50 later and see how its capstains are doing.
 
Indeed, I do have a reflow oven that can keep a constant low temperature for a specific time, is there an official document on it?

The problem I've heard is that the fix is temporary, and since the tapes don't have anything I care about it's best not to keep them around and have them contaminate a drive in a year.

Oddly enough a pair of Compactape II tapes (true TK70 ones) in the same box work fine with no issues. Maybe it was a bad batch of tapes from the factory.
 
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