[vcf-midatlantic] PDP-11 RL02 Locations?

Dave McGuire mcguire at neurotica.com
Sat May 25 18:29:15 EDT 2019

On 5/25/19 5:47 PM, W2HX via vcf-midatlantic wrote:
> Still working (slooooowly) on getting a PDP (or two) up and running. I am now ready to mount two RL02s into a small DEC rack cabinet from which they came.


> I can fit two RL02s into one rack (with the CPU as well).  I have 5 RL02 drives numbered 0,0,1,1,3. Meaning I have 2 zeroes, 2 ones, and one three.
> My question is whether there there is a standard about the  location of the drive numbers. Let me clarify, I know that I can change the number by moving the numbered light cover so this is easily changeable. But in a data center, was 0 typically on top? Or 1?

  Drive 0 is typically on top, but as you note, there is no technical
requirement for this.

> I am not sure which operating system I will run (probably several). If drive 0 is treated differently than the others (for booting for example) then it might make sense to have 0 on the top where I can access the drive from the top without needing to extend the drive. Or, if any operating system can be booted off any drive number, then maybe it truly makes no difference.

  Drive 0 isn't special; any of the boot ROMs that support the
RL11/RLV11/RLV12 will take a parameter specifying which device to boot from.


Dave McGuire, AK4HZ
New Kensington, PA

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