PDP 11/73 is ALIVE!

From: Kevin Handy <kth_at_srv.net>
Date: Mon Nov 24 09:11:26 2003

der Mouse wrote:

>>>[...], and the tape drive started to whir! It seeked back and forth
>>>in tiny and equal increments. Then, the drive stopped and 012710
>>>was displayed, then the _at_ prompt. I typed g, and got:
>>>*** THIS VOLUME DOES NOT CONTAIN A HARDWARE BOOTABLE SYSTEM ***.
>>>
>>>
>>OK, this means (a) the tape boot works, (b) the machine is basically
>>OK, and (c) the tape connection is OK (now). Progress!
>>
>>
>
>Yes! This is very encouraging.
>
>
>
>>Since the "*** THIS VOLUME" ... comes from the boot loader (it is not
>>in the bootstrap program...) on tape, we *did* load something from
>>it.
>>
>>
>
>Not quite. It comes from the boot loader obtained somehow from the
>tape interface. We do not know whether the controller got it from ROM
>on the controller, from ROM on the drive, or from stuff read off the
>tape. My guess would be it's part of the code DMAed into low memory
>(from ROM somewhere), not part of something read from the tape, simply
>because it makes sense for there to be a complaint in case someone
>tries to boot from a totally garbage tape, and this message looks very
>much like what I'd expect that complaint to be.
>
>
>
>>Even though we were able to load the secondary bootstrap off tape
>>(which is blocks 0 and/or 1 on tape), we **ALSO** need to have that
>>code know what we're loading from.
>>
>>
>
>Yes...except that we don't actually know we loaded anything off the
>tape (see above).
>
>
>
>>Either the tape is a "ANSI standard" tape of some kind (with valid
>>boot blocks, but no bootable system) or it is a regular bootable
>>tape, but with a boot block for TM11 controllers...
>>
>>
>
>Or it's a nonbootable tape, and the message came from the ROMed boot
>code DMAed into low core.
>
>
>
Or the heads on the tape drive are dirty. Look at them, and try
cleaning them with a good quality alcohol.
Received on Mon Nov 24 2003 - 09:11:26 GMT