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Making progress with RL02 Drives

Posted <2017-11-10 Fri 23:05> by Aaron S. Jackson.

I have managed to get the RL02 drive to talk to the controller without a terminator by keeping the cable incredibly short (about 15cm).

It seems I can read the control status register (CSR):

C D     E           D      C      I     E        F         D
O R     R           R      N      N     X        U         R
M I     R           I      T      T     T        N         I
P V     O           V      R      E     E        C         V
  E     R           E      L      R     N        T         E
E                                 R     S        I
R E     C           S      R      U     I        O         R
R R     O           E      D      P     O        N         D
  R     D           L      Y      T     N                  Y

1 1     0 0 0 0     0 0    1      0     0 0      1 1 0     0

I have added some headers to these so I can refer back to it later. The drive ready bit (LSB) changes between 0 and 1 depending on whether I have the load button pressed on the drive.

I'm not sure why the composite error and drive error flags are active. If I had to take a guess it was because of what I describe next.

VTserver is compiled and connected up to the PDP-11. I have it set to bootstrap itself and then run the copy program, which it also has to copy to memory first. This was surprisingly easy and only took a few minutes.

However, I want to copy from the RL02 drive to make a dump of the drive, but doing so results in something like this:

Enter name of input record/device: rl(0,0,0)

Can't get rl(0,0,0) sts
rl(0,0,0) err cy=0, hd=0, sc=2, rlcs=142205, rlmp=0
rl(0,0,0) error reading labelsector
Enter name of input record/device:

As you can see, it doesn't seem to happy about reading from the drive. So, I need to figure out whether this is an issue with the controller in the PDP-11 or the RL02 drive itself. I have a couple of spare logic boards for the RL02 drives, so perhaps I can try quickly swapping one out to see what happens.

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