[Simh] The Interconnect Task Force

[Bob Supnik]

The RC25 (code named Aztec) got started as I was leaving Storage 
Engineering. Mike Riggle, VP of Storage Advanced Development (and later 
Storage Engineering), recognized early on that to improve seek and 
rotational performance, disk diameters (14" for the RA8X series) had to 
shrink; 8" or 9" would be the next target. Mike wanted to do only sealed 
(Winchester) disks, but there was significant marketing pressure for a 
low-end removable disk to succeed the RK11, RK611, and RL11. Hence 
Aztec, later the RC25. LESI was, I believe, an attempt to cost-reduce 
the RA8X's radial disk interconnect while maintaining performance.

The RC25 was pretty much a disaster, technically and financially, and 
the end of the line for DEC's removable disk program. Low end systems 
went with ST504-compatible 5.25" sealed disks (the RDXX family), while 
the high-end went with 8" or 9" RA9X series, which used the RA8X radial 
interconnect. ST504 was eventually replaced by SCSI (and later its 
clusterable proprietary variant, DSSI).

/Bob

On 6/25/2019 7:22 PM, Robert Armstrong wrote:
>> Bob Supnik [bob at supnik.org] wrote:
>> Ah, yes, the Interconnect Task Force. 1980, perhaps?
>> ....
>    Can you say anything about LESI, "Low End Storage Interconnect"?  It was used by the RC25 and the TU81+ and, AFAIK, that's it.  It never really went anywhere and there's basically no documentation on it that I've ever seen.  I always wondered about the story behind that.
>
> Thanks,
> Bob
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