PDP-8a boot ROM's for os8serialdisk

[anders_bzn]

I have built and restored another PDP8a system during the late winter and the spring. More to read: http://www.pdp-9.net/pdp-8a-100

I also made boot ROM's for the KM8-A card so that I can boot OS/8 using Kyle Owen's os8diskserver with just a push on the boot button on the frontpanel. If someone are interested in those I have put the ROM images here: http://www.pdp-9.net/docs/pdp-8a-boot-roms/km8-a-serialdisk-boot-prom.zip

Enjoy!

 

[Crawford]

Anders,

Nice work! Did you use the regular bipolar proms 256x4? If so, how did you program them?

(I used 22v10 GAL chips that had their own challenges)

-Crawford

 

[anders_bzn]

Thanks,

I used Signetics N82S126N 256x4 PROM's. Those can be programmed with my old ALL03 programmer.

 

[m_thompson]

I modified the OS/8 boot program so that it could boot from device /SD, the serial disk server.

 

[anders_bzn]

Michel, please explain more! I'm still a newbie on OS/8

 

[m_thompson]

OS/8 has a program called boot. Once OS/8 is booted, you can boot from other media. It is convenient if you only have the MI8E for diskette, and you want to boot from DECtape.

I modified the source for boot, and added the same bootstrap that you just put into ROMs.

BOOT.SV Boot From a Device

@CALLING COMMANDS:
.BOOT/DV

@SWITCHES:
/CA TA8E CASSETTE CAPS-8
/DK ANY DISK
/DL LINCTAPE DIAL
/DM ANY DISK DISK MONITOR
/DT ANY TAPE
/LT LINCTAPE
/PT PT8E (LOADS BINLDR)
/RE RK8E DISK
/RF RF08,DF32 DISKS
/RK RK8 DISK
/RX RX8E FLOPPY DISK
/TD TD8E DECTAPE
/TY TYPESET (UNIT 4)
/VE VERSION #
/TC TC08 DECTAPE ALL SYSTEMS
/ZE ZEROES CORE (FIELD 0)

DEVICES ARE UNIT 0 IF NOT SPECIFIED

DV. HALT AFTER LOADING BOOTSTRAP

 

[anders_bzn]

Ok, that another way to solve it. But I guess you have to boot from a known media (like diskette) before you can boot into the serial disk server.

 

[m_thompson]

Ok, that another way to solve it. But I guess you have to boot from a known media (like diskette) before you can boot into the serial disk server.

I have an MI8E configured to boot from the RX8E. I can toggle the SW switch, and then BOOT/SD. I can also boot from the RK8E and then BOOT/SD.