RK05/RL02 Boot Sequence

From: Paul Koning <pkoning_at_equallogic.com>
Date: Fri Jul 2 08:06:47 2004

>>>>> "Tony" == Tony Duell <ard_at_p850ug1.demon.co.uk> writes:

>> Hello list, I'm trying to figure out the boot sequence on both the
>> RK05 and RL02 drive from a PDP. Here's how I understand it so far:
>>
>> 1. Get the bootstrap in core either via the FP or PTR.

 Tony> Or from ROM (originally diode matrix [1]. later on bipolar PROM
 Tony> chips)

 Tony> [1] Chosen, I am told, because the user could program it
 Tony> without special equipment like a PROM programmer. All you
 Tony> needed was a pair of cutters (the 'blank' boards shipped with
 Tony> all the diodes fitted), and a soldering iron to correct errors.

That's certainly a benefit. Another likely reason is that PROMs
didn't exist yet (only, if anything, mask ROMs, which didn't make
sense in quantities less than 1 million). And even if PROMs existed
back then, 256 diodes were likely to be cheaper.

      paul
Received on Fri Jul 02 2004 - 08:06:47 BST