Ken Wallewein did hardware support for Ontels in the late 1970s. Here are some of his reminiscences, related to me in May 2019:
For a while in the late seventies, I did service tech work on a few Ontel (ODP) hotel booking systems. They were in cities a few hundred miles apart, resulting in some long drives in the wee hours of night.
I thought they were interesting because each installation comprised of a pair or more of 8-bit systems sharing access to hard drives. Some handled front desk interactive work, and others did background processing and reporting. It was pretty impressive what they (theoretically) could accomplish with those 8-bit systems and shared 10MB hard drives. I don't believe they were networked at all, it was all done via shared drive access.
We didn't have much problem with the processor systems per se, but the hard drives were a continuous trouble point, likely due to the environment. I have never worked before or after with drives where I had to use alcohol wipes to clean the platters, and an oscilloscope to align the heads. We had one occasion where the head positioning output servo transistors both blew. Looking at the schematics, I saw they were power Darlingtons - but, being a weekend, any electronic wholesale parts distributors were closed, and it was a smallish town hundreds of miles from a larger center. But there was a Radio Shack, and they had power Darlingtons with a sufficient power rating. I got to thinking, hey, how different could Darlingtons be? So I put them in, and they worked!
I believe the hotel chain dropped use of the systems. They weren't willing to put environment controls in place. Always wondered what happened to Ontel.
Ken Wallewein May 2019