BOOT.SV OS/8 tool to boot devices

After I got a nice pdp8/a (2 RL02 drives and one RX02 drive) together with some RL02 cartridges, saving of this media has to be done.

So I needed some media to put the data on. The RL02 drives are quite big, consisting of 5 devices (R20A:- R20E:) in the system each with maximum blocksize. I integrated the os8diskserver into the build of a RX01 floppy to access SDA0:-SDB1: of the os8diskserver.:



KL8E: *TTY  

R2SY:  SYS  

R0AB: *R20A *R20B 

R0CD: *R20C *R20D 

RK05: *RKA0 *RKB0  RKA1  RKB1  RKA2  RKB2  RKA3  RKB3 

R01E: *R20E  R21E 

RX02:  RXA0 *RXA1 

RX8E: *SYS  


I also wanted to be able to boot all the media that are attached to the pdp8/a. This was quite easy with RX01, because this is the configured boot device in this 8/a. But with RL01 and os8diskserver it needed some software. In OS/8 there is the BOOT.SV program. When running it and passing the option /RL it boots to the first RL01 or RL02 drive number 0.

‍ But only if you have a quite late version of BOOT.SV, because the RL drivers came in the late 1970’s. The „best“ I found is BOOTV4.PA from OS/78 V4. This contains RX an RL bootloaders. There is even space for more in it. So it was easy to integrate the bootloader for the os8diskserver (option /SD). This bootloader comes with the os8diskserver distribution. There are two toggle in loaders, I took the older and some bytes longer one (bootloader.pal).

Here is a bootable  floppy image with BOOTVH code/binary for download:

( in pdp8 of simh:

attache rx0 PAL8VH.RX

b rx0


If you want to see the PAL code only :  

the code compiles with PAL8:



than LOAD and SAVE the program:



now you can use it as usual:

.BOOT/RL        to boot RL01 or RL02 devices

.BOOT/SD       to boot SDA0 of os8diskserver

.BOOT/RX       to boot RX01 or RX02 floppys

Maybe this is of interest for some other pdp8/os8diskserver friends.