Re: Humidity control
I worked for ICL as a Mainframe systems consultant in the 80's and 90's working in ICL customer services (SSC & S39SC) at that point all mainframe vendors insisted on air conditioned and humidity controlled environments. We did perform site audits as part of the pre-sales process for new customers and I have worked with customers who were experience higher than normal failures to commission floor and ceiling void cleaning and aircon overhaul's (e.g. where a site was experiencing regular system crashes / disk head failures). The original posted doesn't seem to realise what access we had to engineering data when investigating faults and the level of skill and the persistence the engineering teams when trying to resolve reliability issues. Mainframe computers were the Rolls Royce of IT during this period and the running costs reflected this. Even as a fairly junior consultant I could mobilise whatever technical resources I required from our engineering teams as long as I could provide a viable hypothesis which was backed u by the diagnostic data.
While I was with ICL we did market a range of mall mainframes (S39 30's) for use in office environments but even these were more reliable in a Data centre environment.
Several vendors did marker mid range systems which could operate outside the data centre but no-one would call these mainframes.