A better boot.

06deb3285e7f43917474be0687d2ae7dIn the previous post I got the PDP-11 booting from a tape emulator into the diagnostic system, XXDP.

Next I wanted to move on a bit.

I was given some boxes of RX50 diskettes by a friend of mine. DEC kit can be very picky about floppies and generally wants them pre-formatted. The PDP-11 is no exception. It is possible to format them on a PC I believe but I don’t have a PC with a 5.25″ floppy drive.

I booted the PDP into XXDP and then used that to initialise a floppy diskette. this doesn’t format it, just writes some structure to it.

I next used the COPY/BOOT and COPY/FILES commands to make the diskette bootable and have all of the files that are on the tape.

I now have a bootable floppy 🙂

First boot.

I was a complete novice with the PDP-11 and so I asked for some help on the www.vintage-computer.com forums. Thanks to the help of the folks there I got the machine to boot.


This is what I did…

Downloaded the TU58 emulator from Don’s site here. This enables a PC to emulate a TU58 which is a tape drive unit that talks to the PDP using a serial port.
I downloaded a disk image for the TU58 emulator to load and present to the PDP when asked, from here.

I used Win Xp on my rather old laptop and used Hyperterm on COM1 (19200) to act as my terminal to the PDP.
I started a command prompt on Xp and then started tu58em with the options -p5 -s 9600 -r 11xxdp.dsk. This starts tu58em talking on COM5 at 9600 baud with the disk image mounted as read only.

I had COM1 connected to the console port and COM5 to the printer port.

I started the PDP, watched it go thorough its self test and the numbers 1 to 9 and when it started rattling the RX50 I pressed ctrl-C to break the boot. It asked for a command and I used…


and watched as it started up.

One point I didn’t pick up on until I saw it was that it has both DD0 and DD1 are on the same port. I thought they would be on two serial lines (SLU) and they are not

Now I’ve booted up the PDP I’ll sit down with the manuals and boot myself.