I've Done All The Dumb Things

[Unibus]

Hi,

I have a PiDP-1 Rack with USB for Tape I/O, keyboard and mouse. Attached is a video capture of go,[tab]lac x[return]lup,[tab]cma[return][tab]sar 4s[return] i.e code taken from the Programming the DEC PDP-1 web page.

Some problems:-

• First Tab on line 3 (before the sar 4s) has gone.  Text is shown at the 1 minute mark of the vidro with missing tab. If I had typed [space][tab] it would've tabbed correctly for the instruction. 
• Punched a tape to the USB stick with Sense Switch 6 up (on). On readback after moving the USB stick from the punch to the reader slot with switch 6 up (on) I received parity errors.
• When punching to the USB stick there were two installed (Reader and Punch). On readback only one USB stick (after move from punch to reader) and no files created.
• I double checked the USB assignments and they were OK.
• There were a couple of hidden files on the USBs from the manufacturer. Reformatted the USB sticks and a punch file was produced. Still had parity issues on the read.

What have I done wrong this time?

Regards,

Garry