Editing ICL Direct Machine Environment

{{Short description|Computing mainframe environment}}
{{Use dmy dates|date=April 2022}}
'''Direct Machine Environment''', abbreviated '''DME''', was a [[Mainframe computer|mainframe]] environment for the [[ICL 2900 Series]] of computing systems from [[International Computers Limited]] that was developed in the 1970s. DME was more-or-less an [[ICT 1900 series|ICL 1900]] order code processor in [[microcode]], which permitted the ICL 1900 series executive, [[operating system]]s and [[Library (computer science)|program libraries]] to operate on the ICL 2900 series.<ref>{{cite news | title = ICL woos old users with new software | date = 1997-04-28 | url = https://books.google.com/books?id=Kbm3IWKnstMC&pg=PA198 | work = New Scientist | accessdate = 2011-02-11}}</ref><ref>{{cite web | url = http://www.icl1900.co.uk/techpub/tp3788.djvu | title = TP3788 DME/3 and CME/3 | accessdate = 2011-02-11 | format = DJVU | publisher = ICL}}</ref>

==Reason for Development==

At this time most companies that had computers had large teams of programmers to write their applications. DME was developed so that customers could buy the new hardware and run their 1900 or System 4 applications whilst they developed their replacement [[ICL VME|VME]] applications. This led to some users running DME and VME alternately on the same machine for some years. Unfortunately this led to situations where development teams were waiting around for time to run their new applications. This, and the fact that some users were not moving to the new system, led ICL to develop a system called Concurrent Machine Environment (CME) under which VME ran DME as a subsystem, enabling 1900 and [[English Electric System 4|System 4]] applications to be run on a 2900 or [[ICL Series 39|Series 39]] machine alongside VME applications.

== References ==

<references/>

{{ICL hardware|DME}}

[[Category:ICL operating systems|Direct Machine Environment]]


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