[HECnet] RT-11 filesystems, was Re: DECnet-RT?

[Robert Armstrong]

> Thomas DeBellis <tommytimesharing at gmail.com> wrote:
>32MB really was ginormous back in the day ...

  By some standards RT11 was very forward thinking - OS/8 file systems were limited to 4095 OS/8 blocks.  That's somewhere between 1.5 and 2Mb, depending on how you map 12 bit words onto 8 bit bytes.  Partitioning was fixed and built into the OS/8 handlers.  Even the RK05J had two partitions; the RK05F pretended to be two RK05Js, so it had four.  RL01s had three partitions and RL02s had five.  The mapping of partitions on the RL drives was a bit asymmetrical to simplify the arithmetic the handler had to do.  The RD handler for DECmates could assign partitions dynamically, something like the RT11 DU driver.  The SBC6120 did the same thing with IDE/ATA drives.

Bob