Quote:
Originally Posted by georgedb
Thanks for the binaries. I own an issue V and they are still called IC2 and IC3
See the pictures.
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Thanks for the images. One thing I notice is that your PROMs (if that is your actual machine in the photos) have blue and green 'dots' attached.
This was Science Of Cambridge's original way of marking programmed 'New OS' PROMs supplied as an upgrade, and probably also those which were supplied as standard with later issues of the machine than mine. With both device numbers being the same but each one having to go in a specific socket, they had to be told apart in some way. The coloured dots were the method chosen. The PROMs in your picture already have their 'dots', so that suggests they are already programmed?
If that is your machine (and it is already working) would you do us a small favour, look at address locations 0000, 0200, 0400 and 0600 and see if they all contain the same data, namely the first byte of the OS?
There was an official 'mod' propagated by Science Of Cambridge which removed the unwanted OS images from the address range 0200-07FF which then made it possible to map an additional 1.5K of offboard RAM into the address range vacated by the unwanted images of the PROM. (See slothie's other recent thread about the MK14 for more about that).
There is a theory that the issue V PCB incorporated this mod.
If it does, you should only see the first bytes of the OS at 0000-onwards, with some other value in memory at 0200-onwards, 0400-onwards and 0600-onwards. I would be interested to know if that is the case.